Abstract
Objective
To explore the long-term effects of a high-intensity exercise intervention on physical activity (PA) in patients with rheumatoid arthritis (RA)
Methods
Eighty-seven patients (84% female), mean age 48 (SD 9.66) years, with a mean disease activity of 2.0 (SD 1.04) (Disease Activity Score based on 28 joints) were included and randomly assigned to an intervention group (IG) comprising 12-week supervised high-intensity interval training (HIIT) on bicycles ergometric, and strength exercise, or to a control group (CG) receiving counselling on the general recommendations for PA and being provided with a home exercise programme. PA was assessed by both accelerometer and self-reports at baseline, at 6 months and at 12 months from baseline.
Results
The majority of the patients (86%) in the exercise group adhered to ≥80% of the 12-week exercise protocol. A significant intervention effect was found for accelerometry-derived ambulatory vigorous PA (4.7 min/day 95% CI 0.82 to 8.51, p=0.0177) at 12-month follow-up, in favour of the IG. The patients in the IG had a higher OR for self-reported PA, including bicycling (6.6 95% CI 1.29 to 34.37, p=0.0239) at 6-month follow-up, and strength exercise at 12-month follow-up (23.1 95% CI 1.64 to 327.13, p=0.0204) compared with the CG. No effects were found for sedentary time and ambulatory moderate PA at 6-month and 12-month follow-up.
Conclusions
The findings of this randomised controlled multicentre study show that patients with RA who participated in 12 weeks of supervised HIIT and strength exercise increased and maintained long-term health-enhancing PA to a greater extent than patients in the CG.
Keywords: Exercises, Physical activity, Physical Therapy, Accelerometer, Randomised controlled trial
WHAT IS ALREADY KNOWN ON THIS TOPIC
General recommendations for health-enhancing physical activity are considered safe and effective for patients with rheumatoid arthritis (RA) and recommended as part of the standard care. However, only a minority of patients adhere to these recommendations.
WHAT THIS STUDY ADDS
A 12-week supervised high-intensity exercise intervention increased the chances of long-term health-enhancing physical activity at 12-month follow-up in patients with RA, whereas counselling on the general recommendations for physical activity and a home exercise programme had no such effects.
HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY
A period of supervised high-intensity exercise may be considered to promote long-term health-enhancing physical activity maintenance in RA.
Introduction
Rheumatoid arthritis (RA) is a chronic progressive autoimmune disease characterised by symmetrically swollen and tender joints.1 Despite more effective control of inflammation by improved pharmacological therapies deterioration in physical fitness,2 prolonged pain and fatigue are still common.3 Moreover, patients with RA have an increased prevalence of cardiovascular diseases (CVD).4 The heightened CVD risk is attributed to the systemic inflammation process in combination with increased prevalence of traditional risk factors,5 6 while increased physical activity (PA) and higher cardiorespiratory fitness level are associated with reduced CVD risk in RA.7 8
The general recommendations for PA have been found to be safe and effective for patients with RA and are recommended as part of the standard treatment.9 However, only a minority of the patients adhere to these recommendations.7 10 Disease-related symptoms such as pain and fatigue,11 a lack of clarity from healthcare professionals about appropriate PA and exercise regimes, and a perceived fear of worsening the disease or damaging the joints have been emphasised to hamper adherence to health-enhancing PA in RA.12 13
We have previously shown that 12 weeks supervised high-intensity exercise significantly improved cardiovascular health, physical fitness and overall health without risk of deterioration of disease activity and pain in patients with RA.14 Maintained exercise is crucial for preserving any health benefits. Wearable devices and self-report methods are commonly used to explore adoption to and maintenance of PA.15 The accelerometer captures different aspects of ambulatory daily activities including walking, running and sedentary time (SED) but do not capture non-ambulatory activities, such as bicycling and strength exercise. Self-report methods can provide additional dimensions of PA but may be affected by measurement errors related to memory, perception, understanding and desirability. Hence, the methods may complement each other to provide a more complete estimation of total PA. The aim of the study was to explore the long-term effects of the high-intensity exercise intervention on PA assessed with accelerometry and self-reported methods in patients with RA.
Methods
This is a secondary analysis of a randomised controlled multicentre trial, evaluating the effects of 12-week supervised high-intensity interval training (HIIT) and strength exercise.14 Patients with RA from rheumatology clinics in western Sweden were recruited via the Swedish Rheumatology Quality Register. The recruitment, intervention and data collection were performed between August 2021 and March 2024. Patients fulfilling the 1987 ACR or the 2010 EULAR criteria for RA,16 17 disease duration >1 year, age 20–60 years, stable treatment on anti-rheumatic drugs for the past 3 months and low-to-moderate disease activity (Disease Activity Score based on 28 joints (DAS28) <5.1) were eligible for inclusion. Exclusion criteria were symptoms of CV disease, other comorbidities, pregnancy and severe physical disabilities precluding high-intensity exercise, engagement in regularly cardiorespiratory exercise on high intensity level (>1 hour/week for the past 6 months) and inability to understand and speak Swedish.
The Consolidated Standards of Reporting Trials (CONSORT) checklist of information to include when reporting a randomised trial is provided in online supplemental eFile 1
Exercise intervention group
Patients allocated to the intervention group (IG) participated in 12 weeks HIIT and strength exercise, following the American College of Sports Medicines recommendations for cardiorespiratory and muscle strength exercise.18 Two sessions per week were supervised face-to-face by a physiotherapist in groups in a hospital setting, exercise individually tailored based on physical capacity and ability. The HIIT session comprised of high-intensity bouts (90%–95% HRmax) interspersed with periods of lower intensity. The strength exercise of large muscle groups included 2–3 sets, 8–10 repetitions, at 70%–80% of one repetition maximum. A third non-supervised cardiorespiratory session of the patient’s own choice was encouraged. The exercise protocol is described in detail in online supplemental eFile 2.
Additionally, motivational strategies were applied during the exercise intervention, including exercise guidance following the principles of self-efficacy and motivational support, an individual exercise diary, the use of heart rate monitors, identification of possible limitations and barriers and continuous dialogue with individual feedback by the physiotherapist.19 Four physiotherapists, all clinical experts within rheumatology and trained in cardiopulmonary resuscitation, guided the exercise. An individual physiotherapeutic consultation was offered to the patients in the IG at the end of the exercise intervention to set up a plan for continued exercise/PA in the participants' own environment, using a person-centred approach. No specific instructions and support from the physiotherapist or reminders regarding PA were given thereafter.
Control group
Patients allocated to the control group (CG) received individual counselling on the general PA recommendations by a physiotherapist and with encouragement to be physically active at moderate intensity ≥150 min/week (aerobic activity). A home exercise programme was provided, and verbal and written instructions were given.14
All patients received standard outpatient care and treatment during the study period at their respective rheumatology clinics.
Outcomes
Outcome measures were assessed at baseline, at 6 months and at 12 months follow-up if not stated otherwise. Information about demographic data and medication was obtained from a questionnaire.
PA was assessed using accelerometry as well as self-reports. The patients were instructed to wear the Axivity accelerometer (AX3, Axivity, UK) in an elastic belt around the waist 24 hours/day for 7 consecutive days, except during water-based activities. Non-wear time, and bedtime and rising time were logged by the patient in an activity diary. Non-wear time was defined as 60 min of zero accelerometer output with allowance of up to 2 min of interruptions.20 A valid day was defined as at least 10 hours and a valid measurement having at least 4 days.21 Raw triaxial data were reduced to measure of PA intensity (milligravity) in three second epochs using an improved method of accelerometer data processing.22,24 Intensity categories were defined relative to maximal weight corrected oxygen uptake (VO2max) measured at baseline, that is, 46%–63% VO2max was defined as relative moderate PA (RMPA min/day) and ≥64% VO2max as relative vigorous PA (RVPA min/day).18 25 SED (min/day) was included and determined as metabolic equivalent of task (MET)<1.5 as there is no definition of this category relative to VO2max.21 For the definition of 1 MET, the oxygen consumption of 3.5 mL/kg/min was assumed.
To explain different aspects of PA, patients were asked to list their exercise modes during the previous week. The listed exercise modes were categorised into relevant categories for analytical purposes.
Weight-adjusted VO2max (mL/min/kg) at baseline was obtained using a maximal cardiopulmonary exercise test, with progressively increasing work on an ergometric bicycle and measured gas exchange.26
Disease activity at baseline was assessed with the DAS28, including clinical assessment of 28 joints (swollen, tender), patient’s rating of health (Visual Analogue Scale; VAS) and sedimentation rate (ESR).27
Pain and overall health at baseline were rated on a VAS (0–100), where a higher rate indicates worse pain and health, related to the rheumatic disease.
Body mass index at baseline was calculated from measured body weight and body height (kg/m2).
All assessors were blinded to group allocation at all study visits.
Randomisation
Randomisation was performed after enrolment, with optimal allocation using a computerised algorithm to balance for sex, age, VO2max and study site. Patients were informed of their group allocation by the physiotherapist supervising the exercise.
Statistical analyses
Descriptive statistics are presented as means and SD, frequency and percentages. The two types of PA variables were included as outcome variables in the analyses of change across the measurement occasions; accelerometer data provided continuous measures of time spent in SED, RMPA and RVPA (min/day), while self-report data provided prevalence of bicycling and strength exercise (binary). Mixed effects modelling was used as it is robust for missing data and handles both systematic and random effects (linear for continuous data (min/day) and generalised linear with logit link for binary data (%)). A random intercept by study ID was included in the models to consider repeated measures within individuals. Separate models were fitted for comparing baseline to 6-month follow-up and baseline to 12-month follow-up. The intervention effect was tested through an interaction term between groups (intervention or control) and measurement occasion (baseline or follow-up) (model 1). In a second model (adjusted model), sex, age, disease activity and group difference in the PA variables at baseline were controlled for. Finally, to control for the effect of baseline PA on change over time, the interaction of baseline PA and measurement occasion was also included in the models. Standardised effect sizes (Cohen’s d) were calculated.
Sample size
The sample size of 87 patients was based on the power calculation of changes in VO2max, the primary outcome in the main study.14 No power calculation was performed on the outcome measures in the present study, however MPA/VPA is closely related to VO2max.
Patient involvement
A patient research partner from the Swedish Rheumatism Association was involved in the study design, the prescreening safety questionnaire and choice of outcome measures.
Results
In total, 87 patients were included in the study, whereof 84% were females. The mean VO2max was 26.3 (SD 5.94) (mL/kg/min) at baseline, indicating a relatively low cardiorespiratory fitness level among the patients. The mean disease duration at baseline was 6.7 (SD 4.90) years (ranging 1–25 years). According to the DAS28 score, 23% of the patients had low-to-moderate disease activity and 77% were in remission. Valid accelerometer measurement was obtained for 84 (96%), 69 (79%) and 66 (76%) patients at baseline, at 6 and at 12 months, respectively. Further details on baseline characteristics of the study population are provided in table 1. Flow of patients is presented in figure 1.
Table 1. Baseline characteristics for the intervention group and the control group.
| Intervention group (n=43) |
Control group (n=44) |
|
|---|---|---|
| Age, years | 48.4 (10.14) | 47.9 (9.27) |
| Sex | ||
| Female | 37 (86.0%) | 36 (81.8%) |
| Male | 6 (14.0%) | 8 (18.2%) |
| Work status | ||
| Full time, 80–100% | 39 (90.7%) | 40 (90.9%) |
| Part time, 1–79% | 3 (7.0%) | 2 (4.5%) |
| Not working | 1 (2.3%) | 2 (4.5%) |
| Education, years | ||
| ≤12 years | 14 (32.6%) | 13 (29.5%) |
| High school, postgraduate | 4 (9.3%) | 4 (9.1%) |
| College, university | 25 (58.1%) | 27 (61.4%) |
| BMI score | 27.1 (5.30) | 27.1 (5.30) |
| Lean | 17 (39.5%) | 17 (38.6%) |
| Overweight | 16 (37.2%) | 17 (38.6%) |
| Obese | 10 (23.2%) | 10 (22.7%) |
| Disease duration, years | 6.1 (4.58) | 6.9 (5.40) |
| Disease activity | ||
| DAS28-ESR | 2.0 (0.90) | 2.0 (1.18) |
| Tender joints | 0.6 (1.91) | 1.0 (4.30) |
| Swollen joints | 0.8 (1.59) | 0.5 (1.00) |
| ESR, mm/hour | 11.0 (11.20) | 11.7 (10.10) |
| VAS Pain, 0–100 | 20.2 (17.57) | 20.1 (20.07) |
| VAS Global, 0–100 | 21.3 (18.25) | 18.5 (18.96) |
| VO2max, ml/kg/min | 26.2 (5.34) | 26.2 (6.54) |
| Medication | ||
| Conventional DMARD | 34 (79.1%) | 32 (72.7%) |
| Biological DMARD | 23 (53.5%) | 21 (47.7%) |
| Targeted synthetic DMARD | 4 (9.3%) | 3 (6.8%) |
| Corticosteroids (oral) | 1 (2.3%) | 2 (4.5%) |
| NSAID | 17 (39.5%) | 18 (40.9%) |
Values are presented as means (SD) and number (%).
BMI, body mass index; DAS28, Disease Activity Score in 28 joints; DMARD, disease‐modifying antirheumatic drug; ESR, sedimentation rate; NSAID, non-steroidal anti-inflammatory drugs; VAS, Visual Analogue Scale; VO2 max, maximal weight corrected oxygen uptake.
Figure 1. Consolidated Standards of Reporting Trials (CONSORT) diagram for the two groups in the randomised control trial.
At baseline, a total of 64.3% in the IG and 64.3% in the CG were defined as being physically active at moderate intensity ≥150 min/week when assessed with accelerometers. There were no significant differences in minutes per day in RMPA (p=0.83), RVPA (p=0.18) and in SED (p=0.65) (table 2). No significant differences were found between the patients that dropped out of the study or lacked valid accelerometer data compared with the rest of the study population in terms of sex, age, VO2max and disease activity.
Table 2. Changes in physical activity from baseline (BL) to 6 months (6M), and from baseline (BL) to 12 months (12M) follow-up between the groups for patients with rheumatoid arthritis.
| Intervention group | Control group | Between group | Adjusted model* | |||||
|---|---|---|---|---|---|---|---|---|
| BL (n=42) |
6M (n=35) |
BL (n=42) |
6M (n=34) |
Intervention effect estimate BL to 6M |
||||
| Means (SD) | Means (SD) | Means (SD) | Means (SD) | Regression coefficient 95% (CI) | P value | 95% (CI) | P value | |
| SED (min/day) | 706.8 (73.78) | 720.5 (76.67) | 716.0 (107.75) |
709.8 (125.04) |
19.4 (−15.38 to 54.21) | 0.2721 | 19.8 (−15.76 to 55.40) | 0.2727 |
| RMPA (min/day) | 35.6 (23.34) | 32.7 (20.66) |
34.4 (28.72) |
30.0 (26.85) |
1.4 (−4.43 to 7.28) | 0.6324 | 1.7 (−3.70 to 7.03) | 0.5414 |
| RVPA (min/day) | 9.5 (13.38) | 8.5 (13.15) |
14.4 (18.73) |
8.2 (11.82) |
4.4 (−0.21 to 8.94) | 0.0612 | 3.4 (−0.50 to 7.28) | 0.0874 |
| OR 95% (CI) | ||||||||
| Bicycling, n (%) | 8 (19.0) |
23 (65.7) |
6 (14.3) |
6 (17.6) |
6.6 (1.29 to 34.27) | 0.0239 | 6.6 (1.27 to 34.38) | 0.0250 |
| Strength exercise, n (%) | 3 (7.1) |
14 (40.0) | 4 (9.5) |
4 (11.4) |
7.0 (0.93 to 52.61) | 0.0582 | 7.6 (0.96 to 60.0) | 0.0550 |
| Intervention group | Control group | Between group | Adjusted model* | |||||
|---|---|---|---|---|---|---|---|---|
| BL (n=42) |
12M (n=34) |
BL (n=42) |
12M (n=32) |
Intervention effect estimate BL to 12M |
||||
| Means (SD) |
Means (SD) |
Means (SD) |
Means (SD) |
Regression coefficient 95% (CI) | P value | 95% (CI) | P value | |
| SED (min/day) | 706.8 (73.78) |
718.2 (62.54) |
716.0 (107.75) |
712.8 (97.99) |
10.9 (−20.54 to 42.38) | 0.4937 | 10.9 (−17.39 to 39.18) | 0.4476 |
| RMPA (min/day) | 35.6 (23.34) |
33.2 (21.22) |
34.4 (28.72) |
29.6 (20.94) |
3.1 (−4.46 to 10.58) | 0.4227 | 3.1 (−2.68 to 8.95) | 0.2881 |
| RVPA (min/day) | 9.5 (13.38) |
8.8 (11.42) |
14.4 (18.73) |
10.5 (15.66) |
4.7 (0.82 to 8.51) | 0.0177 | 3.2 (0.18 to 6.24) | 0.0377 |
| OR 95% (CI) | ||||||||
| Bicycling, n (%) | 8 (19.0) |
16 (47.1) | 6 (14.3) |
4 (12.5) |
4.4 (0.79 to 24.88) | 0.0905 | 4.3 (0.77 to 24.34) | 0.0963 |
| Strength exercise, n (%) | 3 (7.1) |
12 (35.3) | 4 (9.5) |
1 (3.1) |
23.1 (1.64 to 327.13) | 0.0204 | 25.4 (1.74 to 369.56) | 0.0183 |
Bold values indicate statistical significance.
Adjusted model adjusted for sex, age, Disease Activity Score-28 (DAS28) and baseline activity.
RMPA, relative moderate physical activity (≥ 46% VO2max); RVPA, relative vigorous physical activity (≥ 64% VO2max); SED, sedentary.
Adherence and adverse events
A total of 37 (86%) patients adhered to ≥80% of the 12-week prescribed exercise protocol (≥29 of 36 sessions), which included supervised and non-supervised exercises. One patient experienced irregular heart rate during a supervised HIIT session and completed the intervention at moderate intensity after referral to ultrasound cardiography for evaluation of arrhythmia. Four patients reported temporarily increased musculoskeletal pain during strength exercise, which was managed with temporary exercise modification. One patient reported persistent musculoskeletal pain after half of the exercise period and completed the intervention without the strength exercise.
PA at 6-month follow-up
The results demonstrate that the IG maintained or increased their PA level to a larger extent than the CG. A significant intervention effect was found for non-ambulatory PA, with the IG reporting increased bicycling compared with the CG (OR 6.6 95% CI 1.29 to 34.27, p=0.0239). The standardised effect size (Cohen’s d) was large for bicycling, see online supplemental material Table a. No significant intervention effect was seen for RVPA (4.4 min/day 95% CI −0.21 to 8.94, p=0.0612) and for strength exercise (OR 7.0 95% CI 0.93 to 52.61, p=0.0583). No significant intervention effect was found for SED (p=0.2721) and for RMPA (p=0.6324) (table 2).
PA at 12-month follow-up
Similar patterns of change observed at 6 months were also seen at 12 months after baseline, where the IG increased or maintained their PA level to a larger extent than the CG. A significant intervention effect was found for RVPA (4.7 min/day 95% CI 0.82 to 8.51, p=0.0177) and for non-ambulatory PA in terms of strength exercise (OR 23.1 95% CI 1.64 to 327.13, p=0.0204), in favour of the IG. Moreover, the standardised effect size (Cohen’s d) was small for RVPA and large for strength exercise, see online supplemental material Table a. No significant intervention effect was found for SED (p=0.4937) and for RMPA (p=0.4227) (table 2).
Adjusted model for baseline variables
The significant intervention effects at 6-month and 12-month follow-up after baseline were maintained following adjustment for sex, age and baseline values for VO2max, DAS28-score and PA (table 2).
Discussion
The main findings of the present study demonstrate that patients with RA who participated in 12 weeks of supervised HIIT, and strength exercise increased and maintained their PA at 6 and 12 months after inclusion, to a greater extent than patients in the CG.
No major effect was observed between the groups in RMPA at 6 and 12 months follow-up, showing that 63% in the IG and 54% in the CG were physically active at moderate intensity ≥150 min/week at 6 months, and 59%, respectively, 62% at 12 months, that is, reaching the minimal level recommended to obtain health benefits. However, given that vigorous PA is considered substantially more important than moderate PA for optimising cardiac health,28,30 the observed treatment effect in ambulatory vigorous PA at 12 months (4.7 min/day), and supported by a similar pattern at 6 months, indicates that the patients in the IG maintained vigorous PA over time, thereby further improving their CV-health profile. The intervention effect in RVPA corresponds with a group difference of 33 min/week, which constitutes 44% of recommended time on vigorous intensity, thus considered an important finding. A study conducted in healthy individuals demonstrated that every additional minute at vigorous intensity was significantly more strongly associated with improved cardiometabolic health than an equivalent duration at moderate intensity or of sedentary behaviour even after controlling for collinearity among variables.31 These findings support the clinical relevance of the observed effect of ambulatory VPA in the present study.
The positive effect on ambulatory RVPA was accompanied with a significant and strong intervention effect on non-ambulatory activities, involving bicycling and strength exercise. Hence, the patients in the IG were almost seven times more likely to be active with bicycling at 6 months and 23 times more likely to be active with strength exercise at 12 months, compared with the CG. Altogether, the complementary measures from accelerometry and self-reports support an improved PA pattern as a result of the supervised exercise intervention, implying a clinically relevant effect. The findings are in agreement with a previous study of RA, showing that patients engaging in vigorous PA as compared with moderate PA, are more likely to sustain health-enhancing PA over time.32
Maintenance of exercise has been suggested to be highest at the end of an exercise intervention and then tend to decrease over time.33 34 In the present study, 65% of the patients in the IG reported bicycling and 40% strength exercise at 6 months, and similar trend was seen at 12 months. In addition, the maintained RMPA and RVPA pattern to a larger extent in the IG indicates that the patients managed to adhere to their daily routines of ambulatory PA on a health-enhanced level while adding non-ambulatory activities in concordance with the exercise intervention. The maintenance of exercise aligns with a study of axial spondyloarthritis where 60% of the patients in the exercise group reported regular cardiorespiratory exercise and 49% strength exercise 9 months after supervised high-intensity exercise.35 In the same study, 67% of the patients in the exercise group reported long-term PA at moderate-to-vigorous intensity.36
No significant changes were observed in SED during the study period, which suggests that the total study population as a group spend most of their days engaged in sedentary behaviour, in line with previous findings.7 37 Even if the effect was not statistically significant, a small increase in SED was seen in the IG across the follow-ups. This may indicate a compensatory effect, whereby engagement in more structured exercise displaces other forms of PA, potentially leading to increased sedentary behaviour. Similar effects have previously been reported in patient with other chronic diseases.38
Methodological considerations
This study combines the advantages of accelerometer-based measures and self-report measures to reach a more complete description of the change in PA behaviour. We used relative PA intensity, percentage of baseline maximal oxygen consumption to assess moderate and vigorous PA.18 The advantage of this method is that it may reflect the PA intensity of importance to health more accurately compared with other methods. Previous research has shown that the definitions of PA intensity categories generally used in accelerometer-based research are set too low, even for populations with low fitness levels.25 39 In addition, the accelerometer data processing method used in this study captures the variation in PA intensity and the association with measures of health with more precision.22,24 Consequently, the use of relative intensity and the improved processing method implies that the result of the present study is not comparable with previous accelerometer studies using other measures and methods.
Clinical implications
The results of this study underscore the positive long-term effects of the supervised high-intensity exercise intervention on health-enhancing PA in RA. Some of the findings offer insight for enhancing adherence to and participation in vigorous exercise for patients with RA. Initial support from a physiotherapist, including supervised HIIT sessions and motivational strategies, should be provided for patients with RA not accustomed to the exercise mood. Moreover, to support long-term exercise adherence, limited supervised HIIT booster sessions34 for renewed motivation may increase the chances of maintained exercise. We believe this could be particularly important for patients reporting diminished motivation during follow-up visits to their healthcare providers. However, more research is warranted to explore the patients’ perspective on the optimal delivery of such support.
Strengths and limitations
A major strength of this study is the long-term randomised controlled design, an assessor-blinded approach and combined measures including both accelerometers and self-report methods to assess health-enhancing PA over time. A possible limitation may be that wearing the accelerometer encouraged the patients to be more physically active. However, this effect has previously been shown to be small over a 7-day measurement period.40 A limitation is that waist-worn accelerometers do not capture non-ambulatory activities such as bicycling and strength exercise, both of which were included in the exercise intervention and were commonly reported by the patients in the IG during the follow-up assessments. As a result, the accelerometer-based method may have underestimated the true impact of the intervention on PA. To compensate for this limitation, self-report measures were included. Still, patients may have under-reported or over-reported their exercises due to subjective perception and social desirability. Taken together, these limitations highlight the challenges in accurately assessing PA. A limitation is that prior power calculation was not based on changes in PA assessed by accelerometer, potentially leading to insufficient power to detect true changes in PA patterns. A larger sample size might have revealed meaningful, statistically significant changes in ambulatory VPA at 6 months. Nevertheless, significant effects were observed for RVPA at 12 months and for non-ambulatory activities at 6 and 12 months, corresponding to the intervention, which we believe represent meaningful and clinically relevant outcomes.
Conclusion
A supervised 12-week high-intensity exercise intervention increased and maintained health-enhancing PA over time while counselling of the general recommendations for PA and a home exercise programme had no such effects in patients with RA. The exercise protocol combining supervised HIIT and strength exercise could be recommended to enhance adherence to long-term health-enhancing PA in patients with RA.
Supplementary material
Acknowledgements
The authors thank all patients participating in the study, the patient research partner for the contribution to the study and the study personnel at the Clinical Rheumatology Research Centre at Sahlgrenska University Hospital and at the rheumatology department at Uddevalla hospital. They also thank the physiotherapists at Sahlgrenska University Hospital and Uddevalla Hospital for their help with exercise supervision. A special thanks to Christian Greven at Centre for Lifestyle Intervention, Department of MGAÖ, Sahlgrenska University Hospital for help administrating the accelerometers.
Footnotes
Funding: This work was financed by grants from the Swedish state under the agreement between the Swedish government and the county councils the ALF agreement (grant number ALFGBG-992712, ALGGBG-985902, The Healthcare Board, Region Västra Götaland (grant number FOUREG938803, FOUREG967218, FOUREG980124), the Swedish Rheumatology Association Research Grant (grant number R-931095, R-967316, R-968978, R-980980, R-992689), Rune and Ulla Amlövs Foundation for Rheumatology Research and the Norrbacka-Eugenia Foundation.
Provenance and peer review: Not commissioned; externally peer-reviewed.
Patient consent for publication: Not applicable.
Ethics approval: This study involves human participants and was approved by The National Ethics Committee in Sweden (Dr nr; 2019-05255 and Dr nr; 2021-02899). Participants gave informed consent to participate in the study before taking part.
Data availability free text: The data are available from the corresponding author upon reasonable request.
Patient and public involvement: Patients and/or the public were involved in the design, or conduct, or reporting, or dissemination plans of this research. Refer to the Methods section for further details.
Data availability statement
Data are available upon reasonable request.
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Data Availability Statement
Data are available upon reasonable request.