Vigorous physical activity and physical function are strongly associated with better health in patients with long-standing radiographic axial spondyloarthritis

Caroline Feldthusen; Magnus Hallström; Erik Hulander; Anna Deminger; Helena Forsblad-d’Elia

doi:10.1371/journal.pone.0360248

. 2026 Oct 13;21(10):e0360248. doi: 10.1371/journal.pone.0360248

Vigorous physical activity and physical function are strongly associated with better health in patients with long-standing radiographic axial spondyloarthritis

Caroline Feldthusen ^1,^2,^*, Magnus Hallström ^3,⁴, Erik Hulander ^3,⁵, Anna Deminger ^3,⁴, Helena Forsblad-d’Elia ^3,⁴

Editor: Wesam Gouda⁶

PMCID: PMC13660928 PMID: 42868126

Abstract

Objectives

To evaluate the impact of physical function and level of physical activity on health status and health-related quality of life (HRQoL) in patients with long-standing radiographic axial spondyloarthritis (r-axSpA).

Methods

In total, 141 patients with long-standing r-axSpA were included in this cross-sectional cohort study. Assessments included physical function (Bath Ankylosing Spondylitis Functional Index (BASFI)), spinal mobility (modified Bath Ankylosing Spondylitis Metrology Index (BASMI)), muscle function for leg strength (Timed Stands Test (TST)) and handgrip force (Grippit), amount of self-reported physical activity (vigorous physical activity, moderate physical activity, sedentary behavior), health status by ASAS Health Index (ASAS HI) and HRQoL with Short Form Survey Instrument 36-Item. Multivariable linear regression was used to analyze associations between health status, HRQoL, physical activity, muscle function, and physical function.

Results

The mean (SD) age was 60 (12) years, diagnosis duration was 25 (10) years, and 57% were male. Physical function and vigorous physical activity were the strongest determinants of health status and HRQoL. The models explained approximately 50% of the variation in ASAS HI and the physical aspects of HRQoL and 21% of the mental aspects of HRQoL. Participants displayed good health status (62%) by ASAS HI ≤ 5, reached the recommended level of health-enhancing physical activity (77%), had normal muscle function (TST 82% and Grippit 91%), and demonstrated physical function (55%), and spinal mobility (45%) within reference values.

Conclusion

This study highlights the importance of regular vigorous physical activity in older individuals living with long-standing r-axSpA since it was strongly associated with health status and HRQoL.

Introduction

Radiographic axial spondyloarthritis (r-axSpA) is a chronic rheumatic inflammatory disease that results in long-lasting back pain and stiffness [1–3]. The disease is characterized by inflammation in the axial skeleton, enthesitis, and sometimes peripheral arthritis, as well as, to a varying degree, extra-musculoskeletal manifestations (EMMs): anterior uveitis, inflammatory bowel disease, and psoriasis. In addition to pain and stiffness, the impact on physical function and spinal mobility are crucial for patients with r-axSpA, as well as the impact on muscle function, especially muscle strength in the lower extremities [4]. Health-related outcomes and quality of life are negatively affected [5], and we recently found that both physical and mental health-related quality of life (HRQoL) were reduced in individuals with r-axSpA compared to controls from the general population [6]. Since the disease starts in early adulthood, its lifelong impact on physical function and health can be significant [2,7].

There is generally a decline in spinal mobility over time and a continuation of decrease even after 10 years of disease duration [8]. The continuous progress of structural damage in the spine is observed, according to the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS), especially in male patients [9,10].

Regular physical activity and exercise are a cornerstone in the management of r-axSpA [11]. Physical exercise programs have been shown to have a positive impact on physical function, spinal mobility, muscle function, and quality of life [12,13]. Vigorous high-intensity exercise has also shown effects on disease activity and inflammation [14–16]. However, these results are based on younger patient populations and less is known about the impact of vigorous physical activity on quality of life in older patients with long-standing disease. Furthermore, studies show that people with axSpA participate less in health-enhancing physical activity than population controls, especially vigorous physical activity [17,18]. Thus, little is known about the connection between different levels of physical activity, physical function, and quality of life in older patients with long-standing r-axSpA, and if there are differences between sexes. To develop and provide appropriate rehabilitation interventions for this group of patients, more data about this topic is needed.

The aim of this study was therefore to evaluate physical function, spinal mobility, muscle function, and the amount of different levels of physical activity to determine their influence on health status and HRQoL in patients with long-standing r-axSpA overall and stratified by sex. The secondary aims were to compare physical function, spinal mobility, muscle function, and physical activity in patients with r-axSpA compared to reference values from the general population to put the result into a broader context.

Methods

Study design

Cross-sectional cohort study.

Participants

Patients in western Sweden were initially recruited to a cohort study in 2009 which has been previously described [19]. Inclusion criteria were diagnosis of r-axSpA according to the Modified New York Criteria (mNY) for ankylosing spondylitis (AS) [1] and age > 18 years. Exclusion criteria were psoriasis, inflammatory bowel disease, dementia, pregnancy, and difficulties in understanding Swedish language. The patients enrolled in 2009 were subsequently invited to follow-up examinations after 5-years in 2014 and 13-years in 2022–2023, as part of the Long-term Outcome Ankylosing Spondylitis (LOAS)-study. The present study focuses on the results from the 13-year follow-up in a cross-sectional manner. Out of originally 210 patients, 141 patients were included in the 13-year follow-up study from 05/01/2022 to 01/02/2023, see flowchart in (S1 Fig).

Written informed consent was obtained from all patients, and the study was approved by the Swedish Ethical Review Board (597–08, 2021–03484). The study was performed in compliance with the Declaration of Helsinki.

Outcome measures

Analyzed data included socio-demographic factors (age, sex, disease duration, education (ranging from 1; 9-year compulsory school to 4; college/university), working status), medication, pain, and fatigue registered on Visual Analogue Scales (VAS) (0–100 mm) [20,21], and disease activity using Ankylosing Spondylitis Disease Activity Score (ASDAS) [22,23].

Health status was assessed with ASAS Health Index (ASAS HI) [24,25] ranging from 0 to 17, with a lower score indicating better health status, cut-off values ≤5 for good health, > 5 to <12 for moderate health, and ≥12 for poor health [26]. General health-related quality of life (HRQoL) was rated with the Short Form Survey Instrument 36-Item (SF36) [27] by the physical component summary (PCS) score and the mental component summary (MCS) score, which are standardized combined scores with a mean of 50 and a standard deviation of 10. A score above 50 represents better health than the general Swedish population [27].

Physical tests included spinal mobility measured with the modified Bath Ankylosing Spondylitis Metrology Index (BASMI) [28], range 0–10 (10 = worst) and muscle function measured using the Timed Stands Test (TST) [29] for leg strength, recording the time in seconds for 10 raises from a standard chair, and handgrip force measured using the dynamometer Grippit® (AB Detektor, Göteborg, Sweden) [30], recording the mean value during 10 s measured in Newton (N). For TST, a lower value represents greater leg strength, while for Grippit, a higher value represents greater handgrip force.

Self-reported questionnaires included physical function assessed with the Bath Ankylosing Spondylitis Functional Index (BASFI) [31], range 0–10 (10 = worst). Physical activity was an estimation of the mean physical activity of a regular week, reported for vigorous physical activity (i.e., regular physical exercise that makes you short of breath and sweaty like running, gymnastics, sports), from 0 (no time) to 5 (2 hours or more/week), moderate physical activity (daily activities like brisk walks, gardening, or bicycling) from 0 (no time) to 6 (5 hours or more/week), and sedentary behavior (apart from sleep, i.e., sitting) from 0 (never) to 6 (more than 15 hours/day) [32].

Comparisons with reference values of healthy individuals

Measurements of physical function and physical tests of spinal mobility and muscle function were compared to reference values for a general population. For BASFI scores <1.5 in ages 30–50 years and <2.5 in ages above 50 were considered to correspond to a general population [33] and for BASMI age-matched reference values within or less than the third quartile (Q3) were considered representing normal spinal mobility [34]. TST and Grippit were compared to reference values pooled by age and sex [29,30]. Physical activity was evaluated in relation to the WHO guidelines for health-enhancing physical activity and sedentary behavior [35], i.e., 150–300 minutes moderate-intensity; or 75–150 minutes vigorous intensity; or a combination of these.

Statistics

The study population was described using mean and standard deviation (SD) and/or median and quartile 1(Q1)/quartile 3(Q3) depending on the distribution of the variables. Categorical variables were described with number (n) and percentage (%). Non-parametric tests were used due to not normally distributed variables. Group comparisons were done using the Mann-Whitney U test and correlation analyses using Spearman’s rho. The strength of correlation was based on the predefined thresholds: negligible 0 to ±0.20, weak ± 0.21 to ±0.40, moderate ±0.41 to ±0.60, strong ±0.61 to ±0.80, and very strong ±0.81 to ±1.0 [36]. Regression models, using multivariable linear regression, were developed for the analysis of associations between the dependent variables ASAS- HI, SF36-PCS, and SF36-MCS and the independent variables age, BASFI, BASMI, TST, Grippit, vigorous physical activity, moderate physical activity, and sedentary behavior. The analyses were conducted in all patients and stratified by sex due to the differences in phenotype between sexes. Independent variables were chosen based on hypothetical reasoning and previous reports in the literature. Multicollinearity was examined by the Pearson correlation coefficient, r > 0.7 or r < −0.7, and the variance inflation factor. An analysis of residuals confirmed the assumptions of linearity by checking the residual scatterplots of each model, respectively. All significance tests were two-sided and conducted at the 5% significance level. Analyses were performed using the Statistical Package Software for the Social Sciences, SPSS version 29.0 (SPSS Inc., IBM, Chicago USA).

Results

Descriptive data of the 141 participants with long-standing r-axSpA are presented in Table 1. The mean age (SD) of the population was 60 (12) years with a diagnostic duration of 25 (10) years and 57% were male. Fifty-six % were treated within specialist rheumatology care, the rest within primary care, and 42% were on disease-modifying anti-rheumatic drugs (DMARDs). According to ASDAS, 56% had inactive disease or low disease activity (<2.1). When comparing male and female participants, there was a significant difference between sexes in handgrip force (Grippit) (p < 0.001) and vigorous physical activity (p = 0.019), with male participants displaying greater handgrip force and higher amount of vigorous physical activity than females (Table 2).

Table 1. Characteristics of the patients with radiographic axial spondyloarthritis.

Variables n = 141	n (%)	Mean (SD) or Median (Q1;Q3)	Min–max
Age, years		60 (12)	30–84
Men, n	81 (57)
Time since diagnosis, years†		25 (10)	14–52
Pain VAS, 0–100, score†		26.0 (9.3;50.0)	0–92.0
Fatigue VAS, 0–100, score†		27.5 (11.0;52.8)	0–94.0
ASDAS, score†		2.0 (1.3;2.6)	0.6–4.1
Specialist rheumatology clinic, n	79 (56)
Medication*
csDMARD	24 (17)
bDMARD	49 (35)
tsDMARD	1 (0.7)
Daily NSAID	27 (19)
Work status
Fulltime	62 (44)
Parttime	21 (15)
Not working due to disability	13 (9)
Unemployment	2 (1)
Retirement	43 (31)
Education
compulsory school 9 years	15 (11)
Upper secondary education	45 (32)
Community college	9 (6)
College/University	72 (51)
Physical function
BASFI, 0–10, score		1.9 (1.0;3.6)	0–8.2
BASMI, 0–10, score		2.8 (2.0;4.1)	0.6–7.4
TST, s†		15.2 (12.3;20.0)	8.1–74.2
Grippit, N		292 (220;392)	86–581
Health and quality of life
ASAS HI, 0–17, score		4.0 (2;7)	0–17.0
SF36, PCS, score‡		42.7 (34.5;50.8)	17.6–59.1
SF36, MCS, score‡		49.4 (39.7;54.6)	9.5–62.5

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n=number, s=seconds, N=Newton. †n=140, ‡n=139. VAS = Visual Analogue Scale, ASDAS = Axial Spondyloarthritis Disease Activity Score, DMARD = Disease-Modifying Anti-Rheumatic Drug, csDMARD = conventional synthetic DMARD, bDMARD = biologic DMARD, tsDMARD = targeted synthetic DMARD, NSAID = Non-Steroidal Anti-Inflammatory Drug, BASFI = Bath Ankylosing Spondylitis Functional Index, BASMI = Bath Ankylosing Spondylitis Metrology Index, TST = Timed Stands Test, ASAS HI = Assessment of SpondyloArthritis international Society Health Index, SF36 = Short Form Survey Instrument 36-Item, PCS = Physical Component Summary, MCS = Mental Component Summary. *15 patients were taking csDMARD in combination with bDMARD or tsDMARD.

Table 2. Comparisons between sexes in 141 patients with radiographic axial spondyloarthritis.

Variables	Males (n = 81)	Females (n = 60)	p
Age, years	58 (30–84)	61 (35–80)	0.41
Time since diagnosis, years	23 (14–52)	22 (14–52)	0.32
Pain VAS, 0–100, score	22 (0–82)	32.5 (0–92)	0.23
Fatigue VAS, 0–100, score	22 (0–86)	35 (0–94)	0.29
ASDAS, score	1.9 (0.6–4.1)	2.0 (0.6–3.8)	0.44
Physical function
BASFI, 0–10, score	2.0 (0–8.2)	1.7 (0.04–8.2)	0.40
BASMI, 0–10, score	3.0 (0.6–7.4)	2.7 (0.6–6.8)	0.33
TST, s	15.7 (9.3–39.4)	14.8 (8.1–74.2)	0.21
Grippit, N	383 (106–581)	211 (86–361)	<0.001
Physical activity
Vigorous PA, 0–5, score	3 (0–5)	2 (0–5)	0.019
Moderate PA, 0–6, score	4 (1–6)	4 (0–6)	0.61
Sedentary behaviour, 0–6, score	3 (1–6)	3 (1–6)	0.66
Health and quality of life
ASAS HI, 0–17, score	4 (0–13)	5 (0–17)	0.13
SF36 PCS, score	43.9 (20.5–58.0)	42.2 (17.6–59.1)	0.35
SF36 MCS, score	51.0 (9.5–62.5)	47.8 (10.6–60.5)	0.055

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Values are Median (Range), Mann-Whitney U test. n = number, s = seconds, N = Newton. VAS = Visual Analogue Scale, ASDAS = Axial Spondyloarthritis Disease Activity Score, BASFI = Bath Ankylosing Spondylitis Functional Index, BASMI = Bath Ankylosing Spondylitis Metrology Index, TST = Timed Stands Test, ASAS HI = Assessment of SpondyloArthritis international Society Health Index, SF36 = Short Form Survey Instrument 36-Item, PCS = Physical Component Summary, MCS = Mental Component Summary, PA = Physical Activity.

Health status and HRQoL

Health status and HRQoL assessed with ASAS HI, SF36-PSC, and MSC are displayed in Table 1. For ASAS HI 62% of the participants displayed good health (a score <5). Only 4 participants (2.8%) displayed poor health status (a score >12). No statistically significant differences between sexes could be seen for either health outcome, but a non-significant trend was seen for SF36-MSC in which female participants reported poorer (lower scores <50) mental health than males (Table 2).

Univariate associations between physical function, spinal mobility, muscle function, level of physical activity, health status, and HRQoL.

Correlation analyses for health status and HRQoL are shown in Table 3. Physical function (BASFI) showed strong correlations with both ASAS-HI (r_s = 0.69) and SF36-PCS (r_s = −0.66). Spinal mobility (BASMI), muscle function (TST and Grippit), and vigorous physical activity showed weak to moderate correlations with both ASAS HI and SF36-PCS. Also, age correlated significantly with several measurements as shown in (S1 Table) including spinal mobility (BASMI) (r_s = 0.67), physical function (BASFI) (r_s = 0.44), and muscle strength (TST r_s = 0.55 and Grippit r_s = −0.49).

Table 3. Correlations between health status, health-related quality of life, physical function and physical activity, in 141 patients with radiographic axial spondyloarthritis.

Spearman’s rho (r_s)	ASAS HI	SF36-PCS	SF36-MCS
Variables	r_s n=141	r_s n=139	r_s n=139
Physical function
BASFI (Score)	0.69***	−0.66***	−0.23**
BASMI (Score)	0.40***	−0.40***	−0.01
TST (s)	0.47***	−0.47***	0.01
Grippit (N)	−0.37***	0.34***	0.10
Physical activity
Vigorous PA	−0.40***	0.34***	0.23**
Moderate PA	−0.20*	0.21*	0.17*
Sedentary behaviour	−0.16	0.25**	−0.04

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*p < 0.05, **p < 0.01, ***p < 0.001. n=number, s=seconds, N=Newton. ASAS HI = Assessment of SpondyloArthritis international Society Health Index, SF36 = Short Form Survey Instrument 36-Item, PCS = Physical Component Summary, MCS = Mental Component Summary, BASFI = Bath Ankylosing Spondylitis Functional Index, BASMI = Bath Ankylosing Spondylitis Metrology Index, TST = Timed Stands Test, PA = Physical Activity.

Multivariable linear regression analyses with ASAS HI, SF36-PCS, and SF36-MCS as dependent variables

The models are presented in Table 4, overall and stratified by sex. The independent variables age, BASFI, BASMI, TST, Grippit, vigorous physical activity, moderate physical activity, and sedentary behavior were entered in all models.

Table 4. Linear multivariable regression models of health status and health related quality of life for patients with radiographic axial spondyloarthritis, total group and stratified by sex.

ASAS HI	Total group (N = 140)		Male (N = 80)		Female (N = 60)
Adjusted R²	0.51		0.51		0.57
	B (95% CI)	P value	B (95% CI)	P value	B (95% CI)	P value
Intercept	7.00 (3.25;10.75)	<0.001	3.67 (−2.54;9.89)	0.24	11.57 (4.06;19.08)	0.003
Age	−0.04 (−0.09;0.01)	0.13	−0.04 (−0.11;0.02)	0.19	−0.07 (−0.15;0.02)	0.11
BASFI	1.05 (0.76;1.34)	<0.001	0.96 (0.56;1.36)	<0.001	1.05 (0.63;1.47)	<0.001
BASMI	−0.05 (−0.45;0.36)	0.83	−0.09 (−0.57;0.40)	0.72	−0.05 (−0.50;1.02)	0.49
TST	0.02 (−0.04;0.09)	0.49	0.11 (0.02;0.22)	0.045	−0.05 (−0.13;0.04)	0.28
Grippit	−0.004 (−0.08;0.00)	0.06	0.003(−0.005;0.01)	0.47	−0.02(−0.04;-0.005)	0.009
Vigorous PA	−0.46 (−0.71;-0.21)	<0.001	−0.63 (−0.93;-0.33)	<0.001	−0.22 (−0.66;0.22)	0.32
Moderate PA	−0.05 (−0.31;0.22)	0.74	0.11(−0.24;0.47)	0.52	−0.17 (−0.57;0.24)	0.41
Sedentary behavior	−0.07 (−0.43;0.30)	0.73	−0.23 (−0.70;0.24)	0.33	0.28 (−0.29;0.84)	0.34
SF36 PCS	Total group (N = 138)		Male (N = 79)		Female (N = 59)
Adjusted R²	0.48		0.50		0.49
	B (95% CI)	P value	B (95% CI)	P value	B (95% CI)	P value
Intercept	40.49 (29.78;51.19)	<0.001	42.49(23.67;61.31)	<0.001	41.71(20.73;62.70)	<0.001
Age	0.04 (−0.10;0.19)	0.57	0.04 (−0.16;0.25)	0.66	−0.02 (−0.26;0.22)	0.87
BASFI	−2.41 (−3.23;-1.58)	<0.001	−3.06 (−4.28;-1.84)	<0.001	−1.47 (−2.65;-0.29)	0.02
BASMI	0.35 (−0.80;1.51)	0.55	1.13 (−0.33;2.59)	0.13	−0.46 (−2.58;1.65)	0.66
TST	−0.23 (−0.41;-0.05)	0.01	−0.29 (−0.62;0.04)	0.08	−0.17 (−0.41; 0.06)	0.15
Grippit	0.008 (−0.004;0.02)	0.17	0.01 (−0.009;0.04)	0.22	−0.007 (−0.05;0.03)	0.74
Vigorous PA	0.93 (0.21;1.65)	0.01	0.99 (0.08;1.91)	0.03	1.28 (0.06;2.50)	0.04
Moderate PA	0.31 (−0.45;1.07)	0.42	−0.52 (−1.60;0.57)	0.35	1.44 (0.32;2.56)	0.01
Sedentary behavior	0.73 (−0.32;1.77)	0.17	0.33 (−1.10;1.76)	0.65	0.72 (−0.87;2.31)	0.37
SF36 MCS	Total group (N = 138)		Male (N = 79)		Female (N = 59)
Adjusted R²	0.21		0.08		0.35
	B (95% CI)	P value	B (95% CI)	P value	B (95% CI)	P value
Intercept	27.83 (11.90;43.76)	<0.001	42.21(12.65;71.76)	0.006	23.47(−5.95;52.88)	0.11
Age	0.28 (0.06;0.50)	0.01	0.26 (−0.06;0.57)	0.11	0.37 (0.03,0.70)	0.03
BASFI	−2.87 (−4.10;-1.65)	<0.001	−2.46 (−4.38;-0.55)	0.01	−3.17 (−4.83;-1.52)	<0.001
BASMI	0.50 (−1.21;2.22)	0.56	0.32 (−1.97;2.62)	0.78	−0.62 (−3.58;2.35)	0.68
TST	0.16 (−0.11;0.43)	0.25	0.003 (−0.51;0.52)	0.99	0.14 (−0.20;0.47)	0.41
Grippit	0.008(−0.01;0.03)	0.36	−0.02 (−0.06;0.02)	0.31	0.03 (−0.03;0.09)	0.36
Vigorous PA	1.22 (0.15;2.28)	0.03	0.70 (−0.74;2.14)	0.33	1.77 (0.06;3.48)	0.04
Moderate PA	0.19 (−0.94;1.32)	0.74	0.64 (−1.07;2.35)	0.46	−0.58 (−2.16;0.99)	0.46
Sedentary behavior	−0.58 (−2.14;0.97)	0.46	−0.64 (−2.89;1.61)	0.57	−0.40 (−2.63;1.83)	0.72

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Independent variables: Age, BASFI, BASMI, TST, Grippit, vigorous PA, moderate PA, sedentary behaviour. N = number, B = unstandardized beta coefficients, CI = confidence interval, R² = coefficient of determination. ASAS HI = Assessment of SpondyloArthritis international Society Health Index, SF36 = Short Form Survey Instrument 36-Item, PCS = Physical Component Summary, MCS = Mental Component Summary, BASFI = Bath Ankylosing Spondylitis Functional Index, BASMI = Bath Ankylosing Spondylitis Metrology Index, TST = Timed Stands Test, PA = Physical Activity.

ASAS HI.

In the total group and for the male subgroup, better physical function and a higher amount of vigorous physical activity were associated with better health status. For males, better leg strength was also associated with better health status. In the female subgroup, better physical function and greater handgrip force were associated with better health status. The total variation in ASAS HI was explained by the models by 51% in the total group and 51% and 57% in males and females respectively.

SF36-PCS.

In the total group as well as both subgroups, better physical function and a higher amount of vigorous physical activity were associated with better physical health. In the total group, better leg strength and for the female subgroup, a higher amount of moderate physical activity were also associated with better physical health. The total variation in SF36-PCS was explained by the models by 48% in the total group and 50% and 49% in males and females respectively.

SF36-MCS.

In the total group and the female subgroup, better physical function, lower age, and a higher amount of vigorous physical activity were associated with better mental health. In the male subgroup, only better physical function was associated with better mental health. The total variation in SF36-MCS was explained by the models by 21% in the total group and 35% in females. For the male subgroup, the model only explained 8% of the variation in SF36-MCS.

Comparison of physical function, spinal mobility, muscle function, and physical activity between patients with r-axSpA and reference values from the general population

Data on physical function, spinal mobility, and muscle function in the patients with r-axSpA are shown in Table 1. When adjusting the scores for age and comparing them to the general population, 55% of the participants scored physical function (BASFI) within the cutoff score for healthy controls [33] and 45% of the participants displayed spinal mobility (BASMI) within the normal range [34].

For muscle function stratified by age and sex, 82% of the participants performed within the normal range for leg strength (TST) [29], and 91% within the normal range for handgrip force (Grippit) [30].

The distribution of vigorous physical activity, moderate physical activity, and sedentary behavior is presented in Fig 1. Fifty-one % of the participants engaged in vigorous physical activity >1 hour/week. According to the WHO guidelines, 77% of the participants reached the recommendations for health-enhancing physical activity.

Discussion

The majority of the participants with long-standing r-axSpA displayed good health status assessed by ASAS HI. Physical function and vigorous physical activity were found to be strongly related to health status and the physical component of HRQoL. The models were able to explain approximately 50% of its variation while about 21% of the mental aspects of HRQoL in this study with older patients with r-axSpA.

Physical activity is first-line treatment in the management of axSpA [11] and the result of our study corresponds to the results of another recent study showing associations between physical activity at a moderate level or above and health status in younger patients with axSpA [37]. However, adherence to physical activity recommendations is suggested to be low in people with axSpA, with estimates varying from 17% to 71% [38]. In a general Swedish population in 2022 [39], 66% (age 30–84 years) were physically active at least 150 min/week on a moderate level, and in a previous Swedish questionnaire-based axSpA study, 68% reached this level [40]. In our population, 77% reached the level of health-enhancing physical activity, implying that they were more physically active than the general Swedish population [39] and also more physically active than previous axSpA populations [38,40]. We found that regular vigorous physical activity that makes you short of breath and sweaty seems to have a greater impact on health status than moderate intensity daily activities. This was seen especially among males who also reported engaging in more vigorous physical activity than the female patients. Research on vigorous high-intensity exercise has previously shown effects on both disease activity, inflammation, and physical function as well as fatigue, sleep, and general health in patients with r-axSpA [14,15] and a recent review concluded that aerobic exercise programs have an effect on C-reactive protein (CRP) and disease activity in r-axSpA [16]. However, the results of these studies were based on younger patients with axSpA compared with our older adults. Swinnen TW et al. reported that when compared to healthy individuals, time spent in light or moderate physical activity did not differ between patients with r-axSpA and healthy individuals, but patients with r-axSpA reported less vigorous physical activity [41]. Interviews with patients participating in high-intensity exercise have shown that this type of exercise is perceived as challenging for both body and mind, but rapid bodily effects resulted in strengthened faith in one’s own body and a changed attitude and motivation for exercise [42]. In our study, 51% of the participants engaged in vigorous physical activities >1hour/week compared to 32% exercising at vigorous intensity for ≥30 minutes 2–3 times/week, in the previous Swedish axSpA cohort [40].

In this study of mostly older patients with longstanding r-axSpA, approximately half of the participants displayed physical function and spinal mobility within the normal range, compared to age-matched reference values of a general population, and the vast majority had normal muscle function. Comparing our result to a recent 10-year follow-up study, the level of disease activity was similar but physical function by BASFI and health status by ASAS HI were better in our cohort despite higher age (60 years compared to 44 years) [43]. The associations between physical function and health status seen in our study correspond to the results of other recent studies consisting of patients about 15–20 years younger [44–46]. However, these studies also demonstrate associations with disease activity [37,44,45] and sex [44,45] which was not found in our older population. In line with our results, they found no associations between spinal mobility and health status [46]. However, comparison of disability and health status between different r-axSpA cohorts might introduce biases. The organization of healthcare differs between countries. Our study included patients who were followed both in specialized rheumatology care as well as in primary care. The patients in primary care are not treated with DMARDs and may represent a healthier group but might also be an undertreated group. Further, the disability profile of r-axSpA is evolving due to the biological era, which suggests decreased functional impairment over time [47]. In our study, we saw an association between age and a decline in physical function and spinal mobility which may be due to disease duration. However, such decline is also seen in a normal population, indicating that age itself is associated with decreasing mobility and physical function [33,34]. No differences in physical function and spinal mobility were seen between sexes, and normative reference values for BASFI and BASMI recommend adjustment to age but not sex [33,34]. However, male patients with r-axSpA often display worse BASMI values than females with r-axSpA [10] while BASFI is often found without a clear difference between the sexes [48]. Both BASFI and BASMI are composite scores based on several questions and measures respectively. Despite the absence of sex differences in composite scores, the score of individual questions/measures may differ between male and female patients [48].

Limitations of the study include the population sample, which needs to be considered. The participants were initially included in 2009, in a cohort that consisted of 210 patients. This implies that the remaining 141 participants in this study are a selected population whose lifestyle or health literacy may differ from the initial population. The participants represented both rheumatology clinics and primary care, which affects the ability to compare the results to other cohorts, but in turn broadens the generalizability of the results. This study also used self-reported questionnaires, which need to be regarded especially for the reporting of physical activity that may be both overestimated and underestimated [49]. Further, reporting of physical activity differs between studies, which may affect comparisons of physical activity across studies.

Although the majority of the participants in this study reported good health status and physical function, living with this chronic disease is virtually undescribed and could be an important area for future qualitative research. Also, no conclusions can be drawn about causal relationships from this report, which is why studies of causality are warranted, especially with a focus on older patients. High-intensity exercise has recently emerged as an effective treatment in patients with r-axSpA [14–16]. However, none of the studies include older patients. Our study demonstrates the ability to engage in vigorous physical activity also in older age, therefore, future RCTs evaluating the effects of vigorous physical exercise in older patients with r-axSpA are warranted to support recommendations for physical activity in this older population.

Conclusion

Our results show that older individuals with r-axSpA have the ability to engage in vigorous physical activity, even in the later stages of disease, which is associated with good health outcomes. Approximately half of the participants displayed physical function and spinal mobility within normal range and the vast majority had normal muscle function.

Supporting information

S1 Fig. Flowchart.

Flowchart of the inclusion in the Long-term Outcome Ankylosing Spondylitis (LOAS)-cohort in western Sweden.

(DOCX)

pone.0360248.s001.docx^{(24.8KB, docx)}

S1 Table. Univariate associations.

Correlations between age, physical function and physical activity in patients with radiographic axial spondylarthritis.

(DOCX)

pone.0360248.s002.docx^{(16.4KB, docx)}

Acknowledgments

The authors thank all patients who participated in the study. We also thank Beryl Svanberg, research partner from the Swedish Rheumatoid Association, and the Clinical Rheumatology Research Center (KRF) at the Rheumatology Clinic at Sahlgrenska University Hospital.

Data Availability

The data contain sensitive personal information and because of the risk of re-identification, disclosure of data would require a secrecy assessment according to Swedish law. Data can be assessed, after secrecy assessment, from the Swedish Ethical Review Board (597–08, 2021-03484), dataskyddsombud@etikprovning.se.

Funding Statement

This work was supported by grants from Health and Medical Care Committee of the Regional Executive Board, Region Västra Götaland, Award Number: VGFOUREG-383071, VGFOUREG-564511, VGFOUREG-754661 The Swedish state under the agreement between the Swedish government and the county councils, the ALF agreement Award Number: ALFGBG-938395, ALFGBG-965333 Stiftelsen Konung Gustaf V:s 80-årsfond Award Number: FAI-2017-0454, FAI-2019-0560, FAI-2022-0883 The Swedish Association Against Rheumatism Rune och Ulla Amlövs Stiftelse för Neurologisk och Reumatologisk Forskning The Inger Bendix Foundation for Medical Research The Margareta Rheumatology Research Foundation the Gothenburg Society of medicine The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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2. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

Reviewer #1: This article assesses relationships between health status, HRQol and physical activity in relatively elderly patients with e-axSpA using a cross-sectional dataset.

This study revealed that health status and physical activity are closely correlated even in long-standing axial SpA patients.

Several points need to be clarified

1) Influence of lifestyle, daily physical activity, working status, economic status, educational background, etc., so-called social background.

2) Medication

3) If these factors affect health status, a statistical correction is needed.

Reviewer #2: This is a well-conducted and clearly written cross-sectional study based on a long-term r-axSpA cohort. The methodology is sound, with appropriate use of validated instruments (BASFI, BASMI, ASAS-HI, SF-36) and multivariable regression analyses. The handling of non-parametric data, assessment of collinearity, and model validation are all appropriate. The Discussion adequately addresses the limitations regarding potential selection bias and causal inference. Overall, the statistical and methodological quality is sufficient, and the findings are consistent and clinically meaningful.

Reviewer #3: Vigorous physical activity and physical function are strongly associated with better health in patients with long-standing radiographic axial spondyloarthritis (r-axSpA).

This cross-sectional cohort study (N=141), based on registry data obtained from a longitudinal (13-year follow-up) cohort study (N=210), The Long-term Outcome Ankylosing Spondylitis (LOAS)-study in western Sweden (Ref#19, 2012), aim to evaluate physical function, spinal mobility, muscle function, and physical activity in patients with r-axSpA compared to reference values from the general population.

This manuscript is well written, presented results of original research, performed analysis/statistics at a high standard, included study limitations, and provided a well-focused discussion with appropriate conclusion supported by the data. Although this manuscript is technically rigorous and meets the scientific and ethical standard for inclusion in PLOS One, its average level of importance would also be of interest for general rheumatology, physical therapy, or rehabilitation journals (e.g. Annals of Rheumatic Disease, where the authors had published their abstract entitled "Physical function and regular exercise is important for Health-related Quality of life in patients with radiographic axial Spondyloarthritis" in 2024).

Specific Comments to the Authors:

1. On page 6, Comparisons with reference values of health individuals, line 137, consider changing "for BASMI age-matched reference values within the third quartile (Q3)" to "for BASMI age-matched reference values within or less than the third quartile (Q3)" for clarity.

2. On page 9, Health status and HRQoL, line 198, consider changing "female participants reported poorer mental health than males (Table 2)" to "female participants reported poorer (lower scores <50) mental health than males (Table 2)".

3. On page 14, SF36-PCS, line 244-245, consider changing "In the total group, better leg strength and for the female subgroup, a higher amount of moderate physical activity were" to "In the total group (and male subgroup), better leg strength and for the female subgroup, a higher amount of moderate physical activity were" if that is correct.

4. On page 17, Discussion, line 307-308, please clarify why in the current cohort study vigorous physical activity is defined as >1 hour/week, whereas, in the original cohort study it is defined as >30 minutes 2-3 times/week. Are the criteria for defining vigorous physical activity for the two cohorts (N=141 vs N=210, respectively) same/comparable?

5. On page 23, Reference#19, used in reference to page 4, Participants, line 95-96, please clarify if it was Reference#19 or another article which used/defined the term "LOAS" (The Long-term Outcome Ankylosing Spondylitis study).

**********

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: Yes: Andrew L. Wong, MD

**********

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Submitted filename: CFeldthusen review4526.docx

pone.0360248.s003.docx^{(11.9KB, docx)}

PLoS One. 2026 Oct 13;21(10):e0360248. doi: 10.1371/journal.pone.0360248.r002

Author response to Decision Letter 1

16 Jun 2026

Many thanks to the editor and referees for positive response and valuable feedback. We have been taken all comments into consideration and revised the manuscript.

Here are our point by point response to the reviewers comments which has also been uploaded as a separate file.

Reviewer #1: This article assesses relationships between health status, HRQol and physical activity in relatively elderly patients with e-axSpA using a cross-sectional dataset.

This study revealed that health status and physical activity are closely correlated even in long-standing axial SpA patients.

Several points need to be clarified

1) Influence of lifestyle, daily physical activity, working status, economic status, educational background, etc., so-called social background.

Response: We agree that social background also may influence health status. The questionnaire about physical activity that the patients answered was an estimation of the mean physical activities during a regular week. This clarification has now been added in the manuscript in the description of the questionnaire. We therefore have no data on daily physical activity. Neither do we have any detailed information on the patients’ economic status. We do have information regarding working status and educational background which has now been added to table 1.

Since the patient group was rather old (mean age 60 years) and 31% of the patients were retired due to old age, the ability to make reliable statistical assumptions regarding the impact of working status is compromised. Though, we have now, added a variable about working status and retirement in table 1 to make this transparent.

Regarding educational status there were significant but weak correlations between educational status and both ASAS HI (rs= -0.250, p<0.001) and SF36-PCS (rs= 0.228, p<0.001). But educational status did not affect any of the models when entered in the regression model for the total group.

We found no significant difference in work status or educational status between sexes.

2) Medication

Response: Use of medication is presented in table 1. There was a significant correlation between daily use of NSAID and SF36-PCS (rs= -0.203, p<0.05), however negligible. No other significant correlations were found between medication and health status. Use of medication did not affect any of the models when entered in the regression model for the total group.

3) If these factors affect health status, a statistical correction is needed.

Response: We found no influence on health status regarding use of medication or educational status, thus no correction for medication or educational status was needed.

As approximately one third of the patients was retired due to old age and 75% of the rest of the patients were working full time, working status was not considered a reliable factor for the analysis but presented in table 1 to describe the population.

Response: Thank you for your positive comments.

Reviewer #3: Vigorous physical activity and physical function are strongly associated with better health in patients with long-standing radiographic axial spondyloarthritis (r-axSpA).

Response: Thank you for the positive comments!

Specific Comments to the Authors:

Response: Thank you for this suggestion for clarity. We have changed according to your suggestion.

Response: Thank you for being observant. However, for SF36-PCS the p-value for leg strength (TST) for the male subgroup was 0.08. Our cut off was p<0.05, and even if 0.08 is borderline, we chose to consider leg strength as not significant in the male subgroup.

Response: The two studies used different questionnaires with different response options for physical activity. That is the reason for the different definitions of vigorous physical activity in the different cohort studies. However, we find these definitions comparable.

Response: Yes, reference #19 is correct as it is the first published reference in which this long-term follow-up is described.

Attachment

Submitted filename: Response to Reviewers.docx

pone.0360248.s006.docx^{(23.9KB, docx)}

PLoS One. doi: 10.1371/journal.pone.0360248.r003

Decision Letter 1

Wesam Gouda

20 Jul 2026

Dear Dr. Feldthusen,

publication criteria and not, for example, on novelty or perceived impact.

For Lab, Study and Registered Report Protocols: These article types are not expected to include results but may include pilot data.

==============================

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

Reviewer #1: All comments have been addressed

Reviewer #3: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions??>

Reviewer #1: Yes

Reviewer #3: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #1: Yes

Reviewer #3: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #3: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #3: Yes

**********

Reviewer #1: Dear authors,

Thank you for your appropriate response.

You have a guarantee of good quality, enough to publish this article.

Reviewer #3: Vigorous physical activity and physical function are strongly associated with better health in patients with long-standing radiographi8c axial spondyloarthritis.

This cross-sectional cohort study (N=141) re-enrolled in 2022, was based on registry data/enrollment obtained from a longitudinal cohort study (with 13-year follow-up) initially started in 2009 (N=210), The Long-term Outcome Ankylosing Spondylitis (LOAS)- study in western Sweden (Ref #19, 2012), aimed to evaluate physical function, spinal mobility, muscle function, and physical activity in patients with r-axSpA compared to reference values from the general population.

Comments to the Author:

1. On page 4, under Participants, please clarify whether the term "The Long-term Outcome Ankylosing Spondylitis (LOAS)-study was first used to describe the initial cohort enrolled in 2009 (Ref #19) or for the present study cohort re-enrolled in 2022. Similarly, please clarify appropriate time utilization of this term "LOAS" in the supplementary Figure 1. Reference 19 (published in 2012) never used the term "LOAS". Thus, may also want to add in (under References) the first peer-reviewed publication that actually used and defined the term "LOAS".

2. On page 8, under Results, please clarify in the text whether the percent of patients on disease-modifying anti-rheumatic drugs (DMARDs) is correctly at 42%, as according to Table 1 it stated 17% were on csDMARD, 35% were on bDMARD, and 0.7% were on tsDMARD, totaling to 52% (or 52.7%) were on DMARDs.

3. On page 14, under SF36-PCS (and Table 4 on page 12), please clarify the statement "In the total group, better leg strength... were also associated with better physical health." According to Table 4, under SF36 PCS, since the TST p value for both Male (p=0.08) and Female (p=0.15) were nonsignificant, it is not clear to this reviewer how then can be p value for the TST Total group (Male + Female) can mathematically somehow become significant for better physical health/leg strength muscle function. Please recheck the data and p values in Table 4.

**********

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Reviewer #1: Yes: Ichiro Yoshii, president of Yoshii Clinic, Shimanto City, 787-0033 Kochi Prefecture, Japan

Reviewer #3: No

**********

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Submitted filename: CFeldthusen Re-review71926.docx

pone.0360248.s005.docx^{(11.5KB, docx)}

PLoS One. 2026 Oct 13;21(10):e0360248. doi: 10.1371/journal.pone.0360248.r004

Author response to Decision Letter 2

28 Aug 2026

Response to reviewers

PONE-D-25-27651R1

Vigorous physical activity and physical function are strongly associated with better health in patients with long-standing radiographic axial spondyloarthritis.

Journal Requirements:

Response: The reference list has been checked, and no references have been retracted.

There is an erratum for ref 3; Rudwaleit M et al 2009: The correction provides conflict of interest statements of individual authors which were not provided to the paper.

There is also an error published regarding ref 40; Haglund E et al 2012. The error is in a table. The authors state that the error does not affect the conclusion of the article.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #3: (No Response)

________________________________________

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #3: Yes

________________________________________

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #3: Yes

________________________________________

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The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #3: Yes

________________________________________

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Reviewer #1: Yes

Reviewer #3: Yes

________________________________________

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Dear authors,

Thank you for your appropriate response.

You have a guarantee of good quality, enough to publish this article.

Response: Thank you for this positive response

Reviewer #3: Vigorous physical activity and physical function are strongly associated with better health in patients with long-standing radiographi8c axial spondyloarthritis.

Comments to the Author:

Response: Thank you for pointing out this unclarity. It is true that the term LOAS-study was not used to describe the initial cohort but the 13-year follow-up cohort. We have clarified this in page 4 which now states:

“Patients in western Sweden were initially recruited to a cohort study in 2009 which has been previously described [19]. Inclusion criteria were diagnosis of r-axSpA according to the Modified New York Criteria (mNY) for ankylosing spondylitis (AS) [1] and age >18 years. Exclusion criteria were psoriasis, inflammatory bowel disease, dementia, pregnancy, and difficulties in understanding Swedish language. The patients enrolled in 2009 were subsequently invited to follow-up examinations after 5-years in 2014 and after 13-years in 2022-2023. The latter as part of the Long-term Outcome Ankylosing Spondylitis (LOAS)-study (ref PMID: 40660310). The present study focuses on the results from the 13-year follow-up in a cross-sectional manner. Out of originally 210 patients, 141 patients were included in the 13-year follow-up study from 05/01/2022 to 01/02/2023, see flowchart in supplementary Figure 1 (S1 Fig). “

We have added a reference that first defined the LOAS-study and revised the supplementary flowchart figure (S1 Fig) accordingly.

Response: The reason for this is that 15 patients were taking csDMARD in combination with bDMARD or tsDMARD. That is why the total score do not match. To clarify we have added this information as a footnote to the table.

Response: Thank you for being observant. We have rechecked the data and all values are correct. The reason for the p value being significant for the total group and not the subgroups is the larger n which results in significance being achieved.

Attachment

Submitted filename: Response to reviewers R2.docx

pone.0360248.s007.docx^{(20.7KB, docx)}

PLoS One. doi: 10.1371/journal.pone.0360248.r005

Decision Letter 2

Wesam Gouda

7 Sep 2026

Dear Dr. Feldthusen,

Thank you for submitting your manuscript to PLOS One. After careful consideration, we feel that it has merit but does not fully meet PLOS One’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

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We look forward to receiving your revised manuscript.

Kind regards,

Wesam Gouda, MD,PhD

Academic Editor

PLOS One

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If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise.

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

Reviewer #3: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions??>

Reviewer #3: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #3: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #3: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #3: Yes

**********

Reviewer #3: Minor comments to the Author:

1. On page 3, under Introduction, please clarify preference of "(EMMs); anterior uveitis," or "(EMMs), anterior uveitis,".

2. On page S1_Fig, please clarify preference of "un-bolded box" or "bolded box" for "Patients invited to 13-years follow-up in 2022, The LOAS-study N=180".

**********

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Reviewer #3: No

**********

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PLoS One. 2026 Oct 13;21(10):e0360248. doi: 10.1371/journal.pone.0360248.r006

Author response to Decision Letter 3

23 Sep 2026

Response to reviewer

Reviewer #3: Minor comments to the Author:

1. On page 3, under Introduction, please clarify preference of "(EMMs); anterior uveitis," or "(EMMs), anterior uveitis,".

Response: Thank you for this comment. The wording of the sentence has been improved to the following sentence. ”The disease is characterized by inflammation in the axial skeleton, enthesitis, and sometimes peripheral arthritis, as well as, to a varying degree, extra-musculoskeletal manifestations (EMMs): anterior uveitis, inflammatory bowel disease, and psoriasis”.

2. On page S1_Fig, please clarify preference of "un-bolded box" or "bolded box" for "Patients invited to 13-years follow-up in 2022, The LOAS-study N=180".

Response: The bolded boxes describe how many patients that were included at baseline, 5-years follow -up and 12-13 years follow-up, respectively. The un-bolded box describes the recruitment process and the number of patients invited for follow-up, this to make the process transparent. However, that box does not describe the patients included in the actual data collection. Therefor we prefer to keep that box un-bolded.

Attachment

Submitted filename: Response to reviewers 3.docx

pone.0360248.s008.docx^{(14.3KB, docx)}

PLoS One. doi: 10.1371/journal.pone.0360248.r007

Decision Letter 3

Wesam Gouda

24 Sep 2026

Vigorous physical activity and physical function are strongly associated with better health in patients with long-standing radiographic axial spondyloarthritis.

PONE-D-25-27651R3

Dear Dr. Feldthusen,

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Academic Editor

PLOS One

Additional Editor Comments (optional):

Reviewers' comments:

PLoS One. doi: 10.1371/journal.pone.0360248.r008

Acceptance letter

Wesam Gouda

PONE-D-25-27651R3

PLOS One

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Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

S1 Fig. Flowchart.

Flowchart of the inclusion in the Long-term Outcome Ankylosing Spondylitis (LOAS)-cohort in western Sweden.

(DOCX)

pone.0360248.s001.docx^{(24.8KB, docx)}

S1 Table. Univariate associations.

Correlations between age, physical function and physical activity in patients with radiographic axial spondylarthritis.

(DOCX)

pone.0360248.s002.docx^{(16.4KB, docx)}

Attachment

Submitted filename: CFeldthusen review4526.docx

pone.0360248.s003.docx^{(11.9KB, docx)}

Attachment

Submitted filename: Response to Reviewers.docx

pone.0360248.s006.docx^{(23.9KB, docx)}

Attachment

Submitted filename: CFeldthusen Re-review71926.docx

pone.0360248.s005.docx^{(11.5KB, docx)}

Attachment

Submitted filename: Response to reviewers R2.docx

pone.0360248.s007.docx^{(20.7KB, docx)}

Attachment

Submitted filename: Response to reviewers 3.docx

pone.0360248.s008.docx^{(14.3KB, docx)}

Data Availability Statement

[pone.0360248.ref001] 1.van der Linden S, Valkenburg HA, Cats A. Evaluation of diagnostic criteria for ankylosing spondylitis. A proposal for modification of the New York criteria. Arthritis Rheum. 1984;27(4):361–8. doi: 10.1002/art.1780270401 [DOI] [PubMed] [Google Scholar]

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PERMALINK

Vigorous physical activity and physical function are strongly associated with better health in patients with long-standing radiographic axial spondyloarthritis

Caroline Feldthusen

Magnus Hallström

Erik Hulander

Anna Deminger

Helena Forsblad-d’Elia

Roles

Abstract

Objectives

Methods

Results

Conclusion

Introduction

Methods

Study design

Participants

Outcome measures

Comparisons with reference values of healthy individuals

Statistics

Results

Table 1. Characteristics of the patients with radiographic axial spondyloarthritis.

Table 2. Comparisons between sexes in 141 patients with radiographic axial spondyloarthritis.

Health status and HRQoL

Univariate associations between physical function, spinal mobility, muscle function, level of physical activity, health status, and HRQoL.

Table 3. Correlations between health status, health-related quality of life, physical function and physical activity, in 141 patients with radiographic axial spondyloarthritis.

Multivariable linear regression analyses with ASAS HI, SF36-PCS, and SF36-MCS as dependent variables

Table 4. Linear multivariable regression models of health status and health related quality of life for patients with radiographic axial spondyloarthritis, total group and stratified by sex.

ASAS HI.

SF36-PCS.

SF36-MCS.

Comparison of physical function, spinal mobility, muscle function, and physical activity between patients with r-axSpA and reference values from the general population

Fig 1. Physical activity behavior.

Discussion

Conclusion

Supporting information

Acknowledgments

Data Availability

Funding Statement

References

Decision Letter 0

Wesam Gouda

Roles

Author response to Decision Letter 1

Decision Letter 1

Wesam Gouda

Roles

Author response to Decision Letter 2

Decision Letter 2

Wesam Gouda

Roles

Author response to Decision Letter 3

Decision Letter 3

Wesam Gouda

Roles

Acceptance letter

Wesam Gouda

Roles

Associated Data

Supplementary Materials

Data Availability Statement

ACTIONS

PERMALINK

RESOURCES

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