Physical fitness and physical activity in psoriatic arthritis: a systematic review

Abstract

Objectives

Despite the increased cardiometabolic risk in psoriatic arthritis (PsA) and the known beneficial effects of physical fitness (PF) and physical activity (PA) on cardiometabolic health, evidence of the current status of PF and PA in PsA is still unclear. Therefore, this study aimed to systematically review research on PF and PA in PsA.

Methods

A systematic literature search using four databases was performed to include studies examining PF, specifically cardiorespiratory (CRF) and muscular fitness (MF), and PA in patients with PsA (PROSPERO ID 255501). Risk of bias (RoB) assessment was conducted. Due to the diversity of outcomes, a narrative synthesis was used.

Results

Eighteen papers reporting PF and 33 papers examining PA were included. RoB was low in two studies assessing PF and in four PA studies. CRF was evaluated in two studies, indicating CRF levels similar to a sedentary general population. Handgrip strength (HGS) was reduced in PsA compared with healthy controls, but results concerning additional MF parameters were inconclusive. Three studies measured PA objectively and eight studies used a validated PA questionnaire, suggesting a decreased PA level in PsA. A negative impact of low PA and CRF levels on disease onset was observed. In contrast, a potential negative effect of biomechanical loading on disease parameters (disease onset, disease activity, structural joint and enthesial damage) was suggested.

Conclusion

Current literature suggests a reduced PA level and decreased HGS, but is inconclusive regarding additional MF outcomes. Data on CRF are limited in PsA. Further robust methodological longitudinal and interventional research is needed to examine the relation between PF and PA on PsA disease parameters and cardiometabolic risk.

Key messages.

• Handgrip strength seems to be reduced in PsA, however, other muscular and cardiorespiratory fitness parameters remain largely unexplored.

• Current literature suggests a reduced physical activity level in patients with PsA.

• Further exploration of physical fitness and activity in relation to disease outcomes and cardiometabolic risk may improve future PsA management.

Introduction

Psoriatic arthritis (PsA), a chronic inflammatory joint disease affecting 20% of patients with psoriasis (PsO), is characterized by inflammation in the synovium and enthesis as well as by skeletal structural damage [1–3]. PsA presenting symptoms are pain and stiffness, often leading to functionality loss and fatigue [1, 2]. PsA has a high comorbidity burden including cardiometabolic risk factors and diseases as well as psychological comorbidities [4, 5]. Especially, cardiometabolic risk factors are impacting disease management, worsening patients’ clinical status and might be associated with PsA disease onset [6–15]. Together, PsA with its associated conditions is negatively influencing quality of life [13, 16, 17].

The beneficial effect of physical fitness (PF) and physical activity (PA) on cardiometabolic and general health in the general population is largely known [18–21]. PF reflects the ability to perform daily tasks with vigour and alertness, without undue fatigue [20, 22]. It consists of a set of measurable health and skill-related attributes including cardiorespiratory fitness (CRF), muscular strength and endurance, body composition and flexibility, balance, agility, reaction time and power [20, 22]. PA is defined as ‘any bodily movement produced by skeletal muscles that results in energy expenditure above resting (basal) levels’ and broadly encompasses exercise, sports and PA done as part of daily living, occupation, leisure and active transportation [22].

It is likely that improvements in PF and PA in PsA could contribute significantly to an improved disease control and reduced cardiometabolic risk. The adverse effects of unfavourable body composition on PsA, e.g. onset of disease, disease activity, pain, fatigue, physical function and quality of life have been well-documented in previous studies [6, 12–15]. Weight loss interventions were effective in improving body composition, disease activity, physical function as well as anxiety and depression [23, 24]. In contrast, CRF, muscular fitness (MF) and PA have not been extensively studied in PsA. Higher levels of CRF and MF might have beneficial effects on PsA disease by decreasing inflammation as well as reducing the high comorbidity burden [21, 25]. Exercise and PA according to WHO and American College for Sports Medicine guidelines are considered safe and effective and recommended as essential part of the non-pharmacological management of PsA by leading professional societies in rheumatology [8, 9, 26]. In addition, international scientific cardiology societies highlight the importance of PF and regular PA to improve cardiometabolic health in the general population [27, 28].

Current PA guidelines are mainly supported by evidence in patients with osteoarthritis, rheumatoid arthritis (RA) and axial spondylarthritis (SpA) or derived from expert opinion. In contrast, this evidence of PF and PA in PsA is still unclear, highlighting the need for a comprehensive summary of the available data [29]. Therefore, this study aimed to systematically review and appraise the quality of research on PF and PA in patients with PsA.

Methods

This systematic review was conducted in accordance with the methodology of the Cochrane Handbook for Systematic Reviews of Interventions where appropriate and was reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis checklist [30–32]. The protocol was prospectively registered at the PROSPERO database (ID 255501).

Eligibility criteria

We included papers examining PF (CRF and MF) and PA in patients (≥18 years) with a physician-confirmed diagnosis of PsA or classified as PsA according to CASPAR, Moll and Wright or ICD-10 criteria. A mixed population of patients with rheumatic and musculoskeletal diseases (RMDs) was allowed if the proportion of PsA patients was at least 10% and if their results were separately reported. All eligible studies with an interventional or observational study design and a full-text paper written in English or Dutch were included without restrictions regarding publication year. The outcomes of interest were PF and PA and the association with PsA disease characteristics, function, symptoms and quality of life.

Search strategy and study selection

A systematic literature search was conducted from inception to June 2024 in four different electronic databases: Medline, Embase, Web of Science and Cochrane library. A search string was created using Mesh Terms for PubMed and Cochrane, along with Emtree terms for Embase, supplemented by free-text entries. ‘Psoriatic arthritis’ and synonyms were combined with ‘physical therapy’ OR ‘physical activity’ OR ‘physical fitness’ supplemented with related topics of these concepts. The full search string is available in Supplementary Data S1, available at Rheumatology Advances in Practice online. During the search, no filters or limits were applied to make sure no eligible papers were left out.

The search results of the databases were imported in biographic software (EndNote, Clarivate, UK), where the deduplication procedure was conducted. The eligible papers were exported to Rayyan QCRI, an online collaborative tool to review papers [33]. Title and abstract were screened for eligibility by two blinded reviewers (M.K. and T.W.S.). Conflicts were discussed until consensus was reached and involvement of a third rater was not required. A full-text analysis was completed by two reviewers (M.K. and T.W.S.). Additional eligible studies were added from screening references of screened articles.

Due to the extensiveness of the search and to allow sufficient in-depth discussion of all three topics, studies examining a physical therapy approach and PA interventions in PsA have been analysed in a previous systematic review paper [34]. In this review article, articles assessing PF and PA performed in daily life are discussed.

Risk of bias assessment

Risk of bias (RoB) was independently assessed by the reviewers (M.K. and T.W.S.). The Newcastle-Ottawa Scale (NOS) was used for case control, cohort and cross-sectional studies [35]. Of the included randomized controlled trials and single-group intervention studies, only baseline PA and PF data were reported in this systematic review. Therefore, the most appropriate NOS tool was used to assess RoB. There is no definitive cut-off to determine the quality of a study, as all items of the NOS are equally weighted. However, a study with a score of at least seven is generally considered as low RoB and we have added the cut-off value of five stars to define moderate RoB [36]. RoB of Mendelian randomization analyses were evaluated by criticizing the three basic assumptions of this technique [37].

Data extraction and synthesis methods

Data of the included articles were extracted and collected into tables by two reviewers (M.K. and T.W.S.): study characteristics, measurement method of PF or PA, patient characteristics, PF and PA levels, and the association with disease characteristics, pain, function, symptoms and quality of life. A meta-analysis was not possible due to the diversity of measurement methods and outcomes. Tables were created to describe handgrip strength (HGS), sarcopenia, PA level and occupational and biomechanical loading in PsA. A narrative synthesis was used to describe remaining data in the main text. Data of all individual studies were presented in Supplementary Tables S1 and S2, available at Rheumatology Advances in Practice online. Overall, quantitative data were presented as mean (S.D.), except when specifically indicated as mean (95% CI) or median (interquartile range).

Results

Study selection, study characteristics and RoB assessment

The literature search resulted in 12 472 records (Fig. 1). Finally, 18 papers discussing PF and 33 papers examining PA in PsA were included in this review [38–86]. All study characteristics (N = 49) and findings are presented in Supplementary Tables S1 and S2, available at Rheumatology Advances in Practice online. Supplementary Fig. S1, available at Rheumatology Advances in Practice online, presents a summary of the different study designs. Together, the studies (N = 42, excluding two prospective cohort, two Mendelian randomization and three cross-sectional studies with the same population included) had a total of 10 809 patients with PsA with a median sample size of 88 (Min–Max: 7–2390) and a median proportion of female patients of 53% (Min–Max: 14–100%). Disease activity and disease duration were reported in 69% and 83% of the included studies, respectively.

Figure 1.

PRISMA flow diagram of the study selection process

RoB was low in two studies assessing PF and in four assessing PA (RoB assessment of all studies in Supplementary Table S3, available at Rheumatology Advances in Practice online) [40, 42, 56, 59, 66, 72]. Overall, RoB was mainly increased due to selection bias (e.g. insufficient recruitment process or non-representative study population), use of non-validated outcome measures, results not controlled for confounders and an insufficient or unreported response rate.

Physical fitness

Physical fitness consists of several components of which CRF and MF were discussed in this systematic review. CRF in PsA was assessed in two studies only [48, 55]. The mean peak oxygen uptake (VO₂peak) measured by a standardized maximal exercise capacity test was 29.76 ± 7.30 ml/min/kg in PsA patients with low disease activity (N = 61 RoB = low) [48]. In obese patients with low-moderate disease activity, the median estimated VO₂peak assessed by the Astrand’s submaximal ergometric test was 19.5 ml/min/kg (IQR 15.8, 22.9), which was not significantly different from obese controls (N = 41 RoB = moderate). Additionally, a prospective cohort study with a median follow-up of 31 years revealed that a low and medium CRF level in healthy young men was associated with 44% and 19% increased risk to develop PsA, respectively (PsA cases: N = 6133/1228562 RoB = low) [42].

MF in PsA was examined in 16 studies with HGS and muscle mass being the most frequently studied aspects. The average HGS of PsA patients ranged from 11.33 to 56.70 kg and from 231.92 to 285 mmHg (presented in Table 1) [38–40, 43, 44, 47, 52, 55]. Six studies, of which one with low RoB, concluded that HGS of patients with low-high disease activity was significantly lower compared with healthy controls or norm values (i.e. 300 mmHg) [38–40, 43, 47, 55]. In one study, a different evolution of HGS was detected depending on age and sex (RoB = low) [40]. HGS was preserved at younger age and became significantly lower compared with healthy controls from the age of 55 years for female and 75 years for male patients [40]. Three studies focused on the relation of HGS with disease activity and with hand function. Higher HGS in patients with moderate-high disease activity was significantly associated with lower disease activity and improved hand function [38, 43, 52].

Table 1.

Handgrip strength in patients with PsA

Author (year)	RoB	Disease activity	Number of patients %females	Age (years)	HGS measurement	HGS outcomea
Bilberg (2022) [55]	Moderate	Low-moderate	N = 41 63.4%	54.0 y (48.5; 62.0)	Dynamometer: Grippit digital electronic dynamometer (2)	27.32 kg (19.98; 33.23)
Candiri (2022) [38]	High	Moderate-high	N = 36 78%	48.52 y (9.92)	Dynamometer: Baseline Digital Hand dynamometer (1,3)	11.33 kg (8.00; 18.08)
Duruöz (2024) [52]	Moderate	Moderate-high	N = 144 74.3%	45.33 y (11.58)	Dynamometer: Jamar+Digital Dynamometer (1)	19.43 kg (11.57)
Köprülüoglu (2022) [39]	Moderate	Low-moderate	N = 21 81%	55 y (47; 62)	Dynamometer: Lafayette Professional Hand-dynamometer (3)	2.28 kg (0.66)
Liphardt (2020) [40]	Low	Low-moderate	N = 92 52%	54.8 y (11.6)	Dynamometer: Lafayette Professional Hand-dynamometer (2)	M at 35 y; 55 y; 75 y: 56.70 kg; 45.36 kg; 34.02 kg F at 35 y; 55 y; 75 y: 31.75 kg; 24.95 kg; 15.88 kg
Navsarikar (1999) [43]	High	Moderate-high	N = 50 44%	49.2 y (12.4)	Sphygmomanometer	285.0 mmHg (70.0; 300.0)
Sukenik (1994) [47]	High	NI	N = 166 39%	43.46 y (9.74)	Standard recorder	231.92 mmHg (75.90)

^aHGS of dominant or right hand, transformed to HGS expressed in kg if applicable. Expressed in mean (S.D.) or median (Q1; Q3). 1 According recommendations of American Association of Hand Therapists, 2 Maximum value out of 3 attempts, 3 Mean value out of 3 attempts. F: females; M: males; mmHg: millimetres of mercury; N: number; NI: no information; RoB: risk of bias; y: years.

Muscle mass was examined to define the proportion of patients with sarcopenia [41, 44, 45, 50]. Due to different cut-off values defining muscle mass reduction, the prevalence of sarcopenia in PsA ranged between 11.1% and 26.8% (presented in Table 2). However, sarcopenia defined as muscle mass reduction combined with muscle strength impairment was present in 20% of the PsA population (N = 70 36.7% in remission RoB = moderate) [44]. The proportion of PsA patients with reduced muscle mass was not significantly different from healthy controls (RoB = moderate) [41].

Table 2.

Sarcopenia in patients with PsA

Author (year)	RoB	Disease activity	Number of patients %females	Age (years)	Measurement method	Sarcopenia definition	Prevalence of sarcopenia
Barone (2018) [44]	Moderate	36.7% in remission	N = 70 54%	55.3 y (9.1)	MMI: bioelectrical impedance analysis. HGS: Jamar dynamometer	Sarcopenia: MMI <10.75 kg/m² (M) or <6.75 kg/m² (F) AND HGS <20 kg (F) or <30 kg (M) Presarcopenia: MMI <10.75 kg/m² (M) or <6.75 kg/m² (F)	Sarcopenia: ±20% Presarcopenia: 25.7%
Kavadichanda (2022) [45]	Moderate	Low	N = 56 50%	41.3 y (9.28)	ALM/height²: dual energy absorption spectrometry.	Sarcopenia: ALM/height² <7.0 kg/m² (M) or <5.4 kg/m² (F)	Sarcopenia: 26.8%
Krajewska-Włodarczyk (2017) [50]	High	Moderate	N = 51 100%	65.6 y (5.9)	ALM/height² and skeletal MMI: bioimpedance analyser	Sarcopenia: ALM/height² <5.45 kg/m² or skeletal MMI ≤22.1% (severe) and 22.2–27.6% (mild)	Sarcopenia: ALM index: 13.7% Skeletal MMI < 27.6%: 48% Skeletal MMI ≤ 22.1%: 7.8%
Pedreira (2010) [41]	Moderate	Moderate	N = 45 100%	60.5 y (8.7)	Skeletal MMI: Dual-energy X-ray Absorptiometry	Sarcopenia: skeletal MMI < 5.45 kg/m² Obese sarcopenia: sarcopenia AND total body fat by DXA>41% (<60 y) or >43% (≥60 y)	Sarcopenia: 11.1 % Obesity-sarcopenia: 11.1%

Results are presented as proportion (percentage, %). ALM: appendicular lean mass; F: females; M: males; MMI: Muscle Mass Index; N: number; RoB: risk of bias; y: years.

Various other measurement methods were used to evaluate MF, resulting in heterogeneous and rather inconclusive MF estimates in PsA. Grip endurance, pinch strength and hand muscle volume assessed by MRI were additional methods to evaluate MF of the hands, showing lower MF in PsA compared with healthy controls [39, 49, 52, 53]. Pinch strength was associated with worse hand function and signs of structural damage [53]. Next, endurance of the Triceps Surae Muscle evaluated by the heel raise test was significantly decreased in PsA compared with healthy controls, while lower limb strength assessed by the timed stand test was preserved in obese PsA patients [51, 55]. Lastly, the one-repetition maximum test was used to assess MF of limbs and trunk, establishing baseline intensity of resistance training and evaluating muscle strength post-intervention [46, 54].

Physical activity

Physical activity can be measured using objective methods, such as activity monitors and pedometers, or subjective methods, e.g. self-reported PA questionnaires [87]. In this systematic review, PA level and sedentary behaviour were measured in 26 studies [44, 55, 59–82]. Three studies used accelerometery to objectively measure PA (presented in Table 3) [59, 72, 81]. According to accelerometery measurements in two studies, PsA patients with low-moderate disease activity performed moderate-to-vigorous PA (MVPA) during 47 ± 35 min/day (N = 52 RoB = low) and 90.5 ± 40.8 min/day (N = 19 RoB = low), respectively [59, 72]. In the third study, PsA patients spent 25.9 ± 19.4 and 18.7 ± 11.6 min/day in medium and brisk walking, respectively, with in total 6460 ± 2818 steps/day (N = 16 RoB = high) [81]. Comparison of PA levels between PsA (N = 52) and healthy controls (N = 53) in one study showed no significant difference (RoB = low) [59]. Multivariable regression analyses, adjusted for important confounders in two cross-sectional studies, found that higher PA levels measured by accelerometery were significantly associated with lower disease activity and improved daily mood (N = 52, N = 19; RoB = low) [59, 72]. Longitudinal sub-analysis in 36 PsA patients with low-moderate disease activity found a significant correlation between the changes in disease activity and in MVPA over 6 months [59]. No significant relation was observed between PA level and physical function, pain, fatigue, disease impact and negative mood.

Table 3.

Physical activity in PsA measured by objective methods

Author (year)	RoB	Disease activity	Number of patients %females	Age (years)	Measurement method	PA level
Hernandez-Hernandez (2021) [59]	low	low-moderate	N = 52 47%	53 y (13)	ActigraphGT3X (5 days) Cut points (counts/min): • sedentary: 0–99 • light: 100–2019 • moderate: 2020–5998 • vigorous: ≥5999	Mean time spent in (min/day): • sedentary 1128 (208); • light activity 170 (73); • moderate activity 45 (33); • vigorous activity 1.3 (4.3); • MVPA 47 (35)
McGagh (2023) [72]	low	47.4% in MDA	N = 19 42.1%	52 y (11)	GENEActiv® triaxial wrist accelerometer (28 days) Cut points (mg): • inactivity: <30 • light: 30–99.99 • moderate: 100–399.99 • vigorous: ≥400	Mean time spent in (min/day): • inactivity 602 (77); • light PA 237 (68); • MVPA 90.5 (40.8)
Walha (2022) [81]	high	NI	N = 16 75%	54.10 y (9.06)	Sensoria Inc Instrumented sock including 9-axis inertial measurement unit (7 days) Cut points walking (steps/min): • slow: 60–79 • medium: 80–99 • brisk: 100–119 • vigorous: ≥120	Average active time: 3.9 h (1.7), of which 78% spent in stepping activities and 22% spent in purposeful walking Average number of steps/day: 6460 (2818) Time spent in (min/day): • slow walking 4.6 (4.6); • medium walking 25.9 (19.4); • brisk walking 18.7 (11.6); • vigorous ambulation 1.2 (2.0)

Results are expressed in mean (S.D.) or percentage (%). MDA: minimal disease activity; min: minutes; N: number; MVPA: moderate to vigorous physical activity; NI: no information; RoB: risk of bias; y: years.

Nine studies used a validated questionnaire to measure PA (presented in Table 4) [55, 57, 59–61, 73, 75–77]. The use of non-validated measurement methods in the remaining studies led to various results regarding PA level, intensity, frequency and duration. Several studies evaluated the proportion of patients meeting WHO PA recommendations, resulting in a broad range 17–46% using validated PA questionnaires and 32–69% using non-validated methods in PsA patients with similar characteristics [60, 61, 68–70, 73, 79]. This proportion was significantly lower than in healthy controls, though the comparison was performed in one study only (N = 356 RoB = high) [73]. PA level measured by validated PA questionnaires was low-moderate for most PsA patients, with no significant difference from healthy controls in two studies [55, 75–77, 88]. In contrast, one study reported that 61% of PsA patients with low-moderate disease activity fulfilled the criteria of vigorous PA level (N = 36 RoB = low) [59]. Sedentary behaviour (PA <3 h/week and total sitting time >7 h/day) was present in 23% of PsA patients (N = 699 RoB = moderate) [64]. Similar prevalence rates of 29–30% were reported in two other studies, but the measurement method of sedentary lifestyle was not described (N = 227 59% MDA RoB = moderate; N = 166 RoB = high) [63, 82].

Table 4.

Physical activity in PsA measured by subjective methods

Author (year)	RoB	Disease activity	Number of patients %females	Age (years)	Measurement method	PA level
Bilberg (2022) [55]	moderate	low-moderate	N = 41 63.4%	54.0 y (48.5–62.0)	Saltin-Grimby physical activity level scalea	PA level: Sedentary 39%, low 39%, moderate 22%, vigorous 0%
Barone (2018) [44]	moderate	36.7% in remission	N = 70 54%	55.3 y (9.1)	Ratio of total to basal daily energy expenditure	Ratio TEE/BEE : 1.4 (0.2)
Fagni (2023) [71]	high	71% in MDA	N = 7 14%	39.3 y (10.3)	Patient-reported frequency of sports activity	Frequency of sports activity: <1 time/month N = 2; 1 time/month N = 1; 1–2 times/week N = 0; >3 times/week N = 3
Haglund (2013) [70]	high	moderate-high	N = 931 57%	53 y (11)	Three PA questions: intensity, duration and number of days	Meeting WHO recommendations for PA: 68%
Haugeberg (2020) [66]	low	low-moderate	N = 137 50.4%	52.3 y (10.3)	Patient-reported frequency of exercise	Exercise ≥1 time/week: T 45%; M 44.%; F 46%
Hernandez-Hernandez (2021) [59]	low	low-moderate	N = 52 47%	53 y (13)	IPAQa	In subgroup (N = 36): IPAQ-METs/day: 6115 (6024) IPAQ-PA level: low 4%; moderate 35%; vigorous 61%
Larkin (2016) [61]	high	NI	N = 12 58%	44 y (11)	Yale Physical Activity Surveya	Amount of PA time in past week: 16.6 h (13.0) Activity dimensions summary index: 48.7 (17.8) Energy expenditure index: 6910 kcal (5570) Meeting the recommendations for moderate PA: 17%
Meesters (2014) [69]	high	NI	N = 1185 58%	57.6 y (13.5)	PROM, not specified	Meeting WHO recommendations for PA: 69%
Mogard (2022) [60]	high	moderate-high	N = 745 56%	59.7 y (12.4)	IPAQa	Health enhancing PA: T 46%, M 54%, F 40%

Author (year)	RoB	Disease activity	Number of patients %females	Age (years)	Measurement method	PA level
Osman (2023) [73]	high	NI	N = 356 44%	58 y (12)	Self-reported PA in Nord-Trondelag Health Studya	PA level: low 57%; moderate 29%; high 14% Not meeting ACSM PA recommendations: 61%
Pathak (2023) [74]	high	NI	N = 262 44%	45.14 y (12.89)	Patient-reported frequency of exercise	Exercise frequency: never 29%; daily 33%; 2–6 times/week 17%; once a week 10%; 2–4 times/month 6%; <1 time/month 5%
Queiro (2022) [77]	moderate	low-moderate	N = 158 44.79%	49.35 y (13.53)	IPAQa	PA level: PsAID < 4: low 16%; moderate 52%; high 32% PsAID ≥ 4: low 35%; moderate 43%; high 22%
Queiro (2022) [76]						PA level: M: low 22%; moderate 40%; high 39% F: low 23%; moderate 61%; high 17%
Queiro (2023) [75]						PA level: DAPSA ≤ 14: low 18%; moderate 50%; high 36% DAPSA > 14: low 33%; moderate 45%; high 22%
Reich (2023) [78]	moderate	moderate-high	N = 1225 59%	52.1 y (12.3)	Patient-reported frequency of sports	Engaging in sports ≥1 h/week: 53% PsA+no or mild depressive symptoms (N = 875): 57% PsA+moderate depressive symptoms (N = 268): 46% PsA+severe depressive symptoms (N = 102): 29%
Sinnathurai (2018) [68]	moderate	NI	N = 161 59%	55 y (10)	Heart health survey	Physically active: 52% Exercise program as treatment for overweight or obesity: 8%
Vestergaard (2024) [79]	moderate	low-moderate	N = 2390 57.1%	59 y (12)	Danish National Health Survey	<150 min PA weekly: 68%

Author (year)	RoB	Disease activity	Number of patients %females	Age (years)	Measurement method	PA level
Von Ahnen (2023) [80]	high	moderate-high	N = 56 44.6%	51.0 y (13.2)	PROM, not specified	Baseline PA h/week: 2.6 h (4.9)
Wervers (2019) [65]	moderate	low	N = 84 46%	55 y (11)	Questionnaire: regular exercise	Regularly exercising: 48%

^aResults are expressed in mean (S.D.) or percentage (%). Validated PA questionnaire. ACSM: American College of Sports Medicine; BEE: basal daily energy expenditure; DAPSA: Disease Activity in Psoriatic Arthritis Score; h: hours; F: females; IPAQ: International Physical Activity Questionnaire; M: males; MDA: minimal disease activity; MET: metabolic equivalent; min: minutes; MVPA: moderate to vigorous physical activity; N: number; NI: no information; PROM: patient-reported outcome measure; PsAID: psoriatic arthritis impact of disease; RoB: risk of bias; T: total; TEE: total daily energy expenditure; WHO: World Health Organization; y: years.

A higher PA level (measured by the validated PA questionnaire IPAQ) in patients with low-moderate disease activity was significantly associated with reduced disease activity, improved physical function, lower self-reported disease impact and a favourable BMI (N = 53 RoB = low; N = 158 RoB = moderate) [59, 75–77]. Engaging in more than 1 h sports per week as well as a high self-reported PA level were associated with lower prevalence of depression and anxiety in PsA patients with low-high disease activity (N = 1225, N = 2390; RoB = moderate) [78, 79]. However, no significant relation between PA and fatigue, work presenteeism and absenteeism, sleep disturbance and waist–hip ratio was observed in patients with low-high disease activity (N = 53 RoB = low; N = 931 RoB = high; N = 137 RoB = low) [59, 66, 70]. A cross-sectional analysis (age and sex adjusted) suggested that a sedentary lifestyle was associated with a 2.3-fold higher risk to develop osteoporosis (N = 166 RoB = high) [82]. However, a mediation analysis using UK Biobank data suggested that the influence of regular PA on estimated bone mineral density was low in PsA (8% RoB = high) [58].

The level of PA and the risk to develop PsA was examined in a prospective cohort of the general population (excluding prior PsA; follow-up 11 years; PsA cases: 185/36626; RoB = moderate) [57]. Lower PA levels were associated with 22–45% higher risk to develop PsA compared with the highest PA level. Moreover, the combination of a low PA level and unfavourable body composition was associated with a 2-fold increased risk, whereas a high PA level combined with an unfavourable body composition resulted in a relatively lower risk (Hazard ratios of 1.53–1.84). In a Mendelian Randomization study, no causal relation between sedentary behaviour and risk on PsA was observed (RoB = high) [86]. PA in terms of biomechanical loading and the potential negative impact on PsA onset and disease parameters was also investigated (presented in Table 5). A retrospective analysis suggested that PsO patients with occupations requiring heavy weights lifting had a 2.8-higher risk to develop PsA (N = 159 and 159 PsO controls RoB = low) [56]. Other studies suggested that occupational loading as well as exercise had a potential negative effect on structural joint and enthesial damage, while avoiding PA and a sedentary lifestyle seemed to positively influence disease activity [62, 65, 67, 83]. In contrast, no significant increase in inflammatory enthesitis and pain was observed after a badminton session in seven PsA patients with low disease activity (RoB = high) [71].

Table 5.

Impact of occupational and biomechanical loading on PsA onset and disease parameters

Author (year)	RoB	Disease activity	Number of patients %females	Age (years)	Measurement method	Impact of occupational and biomechanical loading on PsA onset and disease parameters
Eder (2011) [56]	low	NI	PsA: N = 159; 44% PsO-controls:  N = 159; 46%	PsA: 44.9 y (13.1) PsO-controls: 48.4 y (13.3)	Occupational load: questionnaire to assess environmental exposures in the previous 10 y	PsO patients that needed to lift heavy weights during their occupation 2.8-higher risk (95% CI 1.51–5.05) to develop PsA. No other significant environmental and occupational biomechanical loading factors.
Fagni (2023) [71]	high	low	N = 7 14%	39.3 y (10.3)	PA exposure: single 60 min session of active badminton training	No significant increase in inflammatory enthesitis (ultrasound) and pain (VAS-pain) after a badminton session.
Michelsen (2017) [67]	moderate	low	N = 141 50%	52.4 y (10.2)	PA: PROM about frequency of physical exercise	Performing regular exercise related with presence of structural damage of the Achilles tendon on ultrasound: OR 1.92 (95% CI 1.16–3.17)
Queiro (2017) [62]	moderate	MDA: 59%	N = 227 46%	53.2 y (12.4)	Sedentary lifestyle: method not specified	Sedentary lifestyle associated with 3.13-higher odds (95% CI 1.50–6.53) to achieve MDA
Wervers (2019) [65]	moderate	low	N = 84 46%	55 y (11)	PA: questionnaire about regular exercise and avoidance of activities	Avoidance of activities significantly associated with lower inflammatory enthesitis scores on ultrasound: β −1.71 (95% CI 0–0.13) P = 0.017 Regular exercise was not significantly associated.
Zhou (2019) [83]	moderate	remission to low	N = 307 41%	56.6 y (11.3)	Occupational load: occupation history questionnaire	Occupations involving repetitive hand movements associated with increased radiographic peripheral joint damage: β 0.16 (S.E. 0.05) P = 0.0007

%: percentage; β: beta coefficient; MDA: minimal disease activity; min: minutes; N: number; NI: no information; OR: odds ratio; P: P-value; PROM: patient-reported outcome measure; PsA: psoriatic arthritis; PsO: psoriasis; RoB: risk of bias; VAS: visual analogue scale; y: years.

Lastly, three studies discussed important barriers of PsA patients to exercise (e.g. lack of time, pain and fatigue; N = 262 RoB = high) and examined beliefs and perspectives regarding PA, e.g. highlighting the importance of PA alongside the medical management and need for adequate advice (N = 59, N = 310; RoB = high) [74, 84, 85].

Discussion

This study aimed to systematically review research on PF and PA in PsA. Despite the increased cardiometabolic risk in PsA and the established beneficial effects of PF and PA on cardiometabolic health at the population level, high-quality evidence on PF and PA in PsA was scarce.

Evidenced by only two studies, CRF (on a cycle ergometer) was not significantly reduced in patients with low-to-moderate PsA disease activity compared with the sedentary general population [55, 89]. This contrasts to prior work where lower CRF levels in other RMD groups were found [88, 90–92]. Differences in disease duration, disease activity, proportion of patients with increased cardiometabolic risk, CRF assessment modalities (e.g. cycle ergometer versus treadmill) or reference value sets (sedentary versus non-sedentary general population) may explain these discrepancies and require further studies in PsA and across RMDs.

HGS and muscle mass were the most studied aspects of MF. For HGS, sex- and age-specific results were not mentioned in the majority of studies, hampering accurate interpretation of results. Compared with healthy controls, low HGS was found in patients with low-high PsA disease activity, similar to RA patients with low-moderate disease activity [38–40, 43, 47, 55]. Interestingly, one of these studies also reported reduced HGS in female PsO patients without musculoskeletal involvement [40]. Decreased HGS was also observed in populations with other non-musculoskeletal chronic diseases (e.g. type II diabetes mellitus, chronic kidney disease and metabolic syndrome) suggesting systemic mechanisms [93–95]. A few non-longitudinal studies included in this review suggested a negative association of HGS with disease activity and hand function in patients with moderate-high PsA disease activity [38, 43, 52]. Sarcopenia results in PsA were heterogeneous and difficult to compare due to different definitions where only one study combined muscle mass and muscle function as recommended by the European Working Group on Sarcopenia in Older People [41, 44, 45, 50, 96]. Presented prevalences of sarcopenia in PsA were similar to well as higher compared with the general population [41, 97]. Further longitudinal research is needed to understand the potential causes and consequences of decreased MF in the (pre)clinical course of PsA.

Remarkably, this review identified only three studies applying an objective PA measurement method, i.e. accelerometery [59, 72, 81]. Most studies used subjective measurements, resulting in a diverse expression of PA level [44, 55, 59–71, 73–80, 82]. MVPA min/week measured by accelerometery were scattered across studies and PA level assessed by validated questionnaires was low to moderate for the majority of patients, but not significantly different from healthy controls [55, 59, 72, 75–77, 88]. Nevertheless, a mean of 6460 steps/day performed by PsA patients measured using accelerometery was below the recommended 7000–9000 steps/day [18, 81]. Using PA questionnaires, the broad range of 17–69% of patients meeting WHO PA recommendations may indicate a lower adherence rate than 72.5% observed in the general population worldwide [98].

A higher PA level was significantly associated with lower disease activity evaluated by cross-sectional studies [59, 72, 75]. This association between PA and PsA disease activity was confirmed by one longitudinal analysis [59]. However, it remains unclear whether high PA is improving disease activity or the reverse. Studies evaluating PA in terms of biomechanical loading suggested that occupational loading as well as exercise have a potential negative effect on structural damage, while avoiding PA and a sedentary lifestyle may positively influence disease activity [62, 65, 67, 83]. The latter findings seem to support the hypothesized role of mechanical loading in the pathogenesis of SpA [99]. However, it should be noted that biomechanical loading depends on the type of PA, daily PA patterns as well as a patient’s loading capacity, including PF status. In RA and SpA, the relation between PA and disease activity is also inconsistent according to a recent systematic review, consisting of mainly non-longitudinal studies evaluating self-reported PA [100]. Noteworthy, recent training programs in SpA patients were well tolerated and even improving disease activity scores [48, 71, 101–104].

Other patient-reported outcome measures, e.g. increased physical function, lower self-reported disease impact and improved mental wellbeing, were significantly related to a higher PA level [59, 72, 77–79]. Interestingly, although pain and fatigue were identified as important barriers to PA by PsA patients, none of the included cross-sectional studies found a significant association [59, 72, 74]. Except for the association of higher self-reported PA and favourable BMI, it is surprising that relations of PF- and PA parameters with cardiometabolic risk in PsA have not been evaluated yet [59]. PF is highly associated with cardiometabolic risk in the general population. Similarly, RMD patients with normal CRF have a more favourable cardiometabolic risk profile [91, 92]. Interestingly, high-intensity interval training studies showed already promising results to positively influence CRF and body composition in patients with PsA [48, 101]. In addition, two cohort studies included in this review observed that a low CRF- and PA level were associated with an increased risk to develop PsA [42, 57]. Further longitudinal and interventional research is needed to gain insight in general and disease-specific parameters influencing PF in PsA and the potential beneficial impact of PF and PA promotion on disease parameters and cardiometabolic risk.

The insufficient methodological quality of the included studies is an important concern. Measurement methods were often inadequate. Especially, future PA studies should prioritize validated PA measures that specify frequency, duration and intensity of PA over a 24-h periods. Also, the study’s recruitment process and response rate were often poorly described, possibly favouring inclusion of more motivated patients. The majority of studies did also not consider several confounders of PF and PA outcomes (e.g. age and sex). Incorporating PA and PF outcomes in longitudinal and randomized study designs will unravel their role in disease processes and cardiometabolic risk.

Some strengths and limitations of this systematic review should be considered. To generate a complete overview of the available literature, a broad search examining PA and PF in PsA was performed. This contributed to heterogeneous outcomes which complicated analysis and synthesis of the results. Given our strong interest in disease management of patients with PsA, we have only included studies reporting results for PsA separately. Consequently, relevant studies might be overlooked, as study populations may consist of a mixed RMD population. Nevertheless, we have strengthened the methodological quality of this systematic review by conducting and reporting according to the recommended guidelines and by prospectively registering the protocol in the PROSPERO database.

In conclusion, high-quality evidence on PF and PA in PsA patients is scarce. Especially, data on CRF in PsA are currently lacking. Literature suggested a reduced PA level, reduced HGS and was inconclusive regarding other MF outcomes. A negative impact of a low PA and CRF levels on disease onset was suggested. In contrast, a potential negative effect of PA in terms of biomechanical loading on disease onset and parameters needs further investigation due to inconclusive results. Further robust methodological longitudinal and interventional research is needed to examine the relation between PF and PA on PsA disease parameters and cardiometabolic risk.

Supplementary material

Supplementary material is available at Rheumatology Advances in Practice online.

Data availability

Data are available on reasonable request to the corresponding author.

Funding

This study was supported by a grant from the Fonds voor Wetenschappelijk ReumaOnderzoek/Fonds pour la Recherche Scientifique en Rhumatologie.

Disclosure statement: The authors have declared no conflicts of interest.