Reducing Muscle Atrophy and Improving Fitness Critical in Juvenile Idiopathic Arthritis

Patients with juvenile idiopathic arthritis (JIA) may have reduced peak oxygen uptake (VO₂peak) and significantly impaired exercise capacity compared with healthy patients, and would benefit from exercise programs geared to reduce muscle atrophy and improve physical fitness, according to results of a systematic review and meta-analysis published in Rheumatology.

Previous research indicates that young people with JIA have reduced cardiorespiratory fitness (CRF), potentially increasing their risk for cardiovascular disease and leading to sedentary lifestyles. Investigators sought to assess CRF among young people with JIA compared with healthy patients.

The Investigators conducted a systematic review and meta-analysis searching Scopus, Web of Science, and PubMed databases from inception to November 2022. Studies utilizing cardiopulmonary-exercise-testing (CPET) to assess differences in determinants of CRF between patients with JIA vs healthy individuals were included in the analysis.

The primary outcome was VO₂peak.

The final analysis included 8 studies (N=538), of which 6 were classified as high-quality and 2 as low-quality, according to the Newcastle-Ottawa-Scale.

The investigators found patients with JIA had significantly lower VO₂peak (weighted mean difference [WMD], -5.95 mL/kg/min; 95% CI, -9.26 to -2.65) vs control patients, with high heterogeneity across studies (I²=84%, P <.00001).

Patients with JIA had significantly impaired exercise duration (standardized mean difference, -0.67; 95% CI, -1.04 to -0.29) vs control patients, with moderate heterogeneity across studies (I²=56%; P =.08). Maximum heart rate showed no significant between-group differences. Overall, patients with JIA had significantly lower exercise capacity vs healthy control patients.

Subgroup analysis (2 studies, n=70) stratified by sex showed girls with JIA had significantly impaired VO₂peak (WMD, -8.23 mL/kg/min; 95% CI, -10.45 to -6.00; I²=0%; P =.70) vs control patients. Comparison of boys with JIA vs control patients (2 studies, n=43) revealed no significant differences in VO₂peak (WMD, -6.00 mL/kg/min; 95% CI, -13.44 to 1.44; I²=54%; P =.14).

This analysis was limited by heterogeneity across included studies. Additionally, lack of data on the primary outcome prevented pooled subgroup analyses. Finally, the literature search was restricted to English-language journals, excluding certain studies.  

The investigators concluded, “Prescription of exercise training programs might prevent deconditioning due to hypoactivity and improve functional ability. Long-term exercise programs, thus might be advisable for patients with JIA to improve physical fitness and reduce muscle atrophy.”