Background: Physical exercise is an important treatment for individuals with axial spondyloarthritis (axSpA). Although high-intensity training (HIT) has been shown to reduce disease symptoms and risk of comorbidity without exacerbating disease activity (1), compliance tends to decrease over time. Increased knowledge is needed on how to optimize and tailor individual exercise programs for continued regular exercising and improved health.

Objective: To study the effects of HIT on aerobic capacity, body composition, disease activity, physical function, health status and fatigue in individuals with axSpA after a 12-week intervention supported by digital coaching.

Methods: Twenty-two individuals (women, n=12), recruited from two rheumatology clinics in southern Sweden, were randomized to a HIT intervention group (HG; n=11) or a control group (CG; n=11). The HG completed three HIT sessions/week, including two interval training sessions (4x4 min), in self-selected activities for 12 weeks. The individuals in the HG were individually coached and had regular support from a physical therapist primarily by digital coaching. The CG continued exercising as usual. Assessment of aerobic capacity (VO2max), body composition (BMI and visceral fat area [cm2]), disease activity (CRP [µg/ml], BASDAI, 0-10 best-worst), physical function (BASFI, 0-10 best-worst), health status (EQ5D, 0-1 worst-best, ASAS health index [ASAS-HI], 0-17 best-worst), and fatigue (fatigue severity scale [FFS], 0-7 best-worst) were sampled at baseline and after 12 weeks. Mean and standard deviation (SD) were used for descriptive statistics. Repeated measures analysis of variance (ANOVA) was used to investigate effect of group (HG*CG) and time (PRE*POST), with a post-hoc analysis using t-tests when ANOVA indicated a significant difference in main effects or interactions. A significance level of p≤0.05 was used. Fisher´s exact test was used to study the effects over time for CRP (as dichotomized variable, > or < 4 µg/ml).

Results: Results presented are part of an ongoing RCT based on 19 individuals (women n=11) that have completed the 12-week follow-up analyses. The participants mean (SD) age was 48 (10) years, BMI 25 (4), VO2max 37 (6) mlO2/kg/min, and BASDAI 2.6 (0.3). No differences were present between the HG (n=9) and the CG group (n=10) at baseline for the studied variables. After 12 weeks of HIT an ANOVA interaction (p<0.05 showed that HG increased their VO2max (6.4 [3.6] mlO2/kg/min; p<0.001) but CG did not. For BMI, visceral fat area, disease activity (BASDAI), physical function (BASFI), fatigue (FFS) no differences in main effects or interactions were found (p>0.05). Health status (EQ5D) showed an ANOVA time main effect (p=0.007) where the HG increased their health status (0.10 [0.06] units; p=0.02) after 12-weeks, but CG did not. For health status measured with ASAS-HI no differences between groups were found. For dichotomized CRP-values no differences were found in either of the group’s pre-post. 

Conclusions: This pilot RCT shows that after 12 weeks of digital-based HIT intervention, the HG increased their aerobic capacity and EQ5D health status compared to CG, while body composition, disease activity, physical function, and fatigue did not show any significant differences between the groups. 

References

(1) Sveaas SH, Bilberg a, Berg IJ, Provan SA, Rollefstad S, Semb AG, et al. high intensity exercise for 3 months reduces disease activity in axial spondyloarthritis (axSpA): a multicentre randomised trial of 100 patients. Br J Sports med. 2019