Effect of high-intensity interval training in physiotherapy primary care for patients with inflammatory arthritis: the ExeHeart randomised controlled trial.

OBJECTIVES: To assess the effect of high-intensity interval training (HIIT) delivered in physiotherapy primary care on the primary outcome of cardiorespiratory fitness (CRF) in patients with inflammatory arthritis (IA). Additionally, to explore the effects of HIIT on secondary outcomes, including cardiovascular disease (CVD) risk factors and disease activity. METHODS: Single-blinded randomised controlled trial with 60 patients randomly assigned to either a control group receiving usual care or an exercise group receiving usual care and 12 weeks of individualised HIIT at 90%-95% peak heart rate. Outcomes were assessed at baseline, 3 months and 6 months post baseline and included CRF measured as peak oxygen uptake (VO2peak), classic CVD risk factors, disease activity, anthropometry and patient-reported physical activity, pain, fatigue, disease impact and exercise beliefs and self-efficacy. RESULTS: Intention-to-treat analysis demonstrated a significant between-group difference in VO2peak at 3 months (2.5 mL/kg/min, 95% CI 0.9 to 4.0) and 6 months (2.6 mL/kg/min, 95% CI 0.8 to 4.3) in favour of the exercise group. A beneficial change in self-reported physical activity in favour of the exercise group was observed at 3 and 6 months. The HIIT intervention was well-tolerated with minimal adverse events and no apparent impact on disease activity. Differences in secondary outcomes related to CVD risk factors, disease impact, pain, fatigue and exercise beliefs and self-efficacy were generally small and non-significant. CONCLUSION: After 12 weeks of supervised HIIT delivered in physiotherapy primary care, patients with IA demonstrated a favourable improvement in CRF, with sustained effects at 6-month follow-up. TRIAL REGISTRATION NUMBER: NCT04922840.

Criterion Validity and Responsiveness of Estimated Cardiorespiratory Fitness Models in Patients with Inflammatory Joint Disease.

Cardiorespiratory fitness (CRF) is an excellent marker of overall health. This study aimed to assess criterion validity and responsiveness of estimated CRF models (eCRF) in patients with inflammatory joint disease (IJD). CRF was measured directly as peak oxygen uptake (VO2peak) by a Cardiopulmonary Exercise Test (CPET), while one generic eCRF model (eCRFGEN) and two disease-specific eCRF models (eCRFALT and eCRFPGA) were used to estimate CRF at baseline and after 3 months in 55 Norwegian patients with IJD. Moderate correlations were observed between eCRFGEN, eCRFALT, eCRFPGA, and VO2peak at baseline (ICC 0.60, 0.64 and 0.62, respectively) and 3 months (ICC 0.62, 0.65 and 0.57, respectively). All eCRF models overestimated measured VO2peak, and there was large variability in agreement of individual measurements at baseline and at 3 months. Weak correlations were observed for responsiveness of eCRFGEN (ICC 0.39), eCRFALT (ICC 0.40) and eCRFPGA (ICC 0.39). Mean differences between change in eCRF models and change in VO2peak were small, but the wide limits of agreement exceeded the pre-defined clinically acceptable margins. The eCRF models possessed adequate ability to detect ≥3.5 mL/kg/min improvement in VO2peak. eCRF may suffice for group-level assessment, but caution is advised when applying eCRF to individual patients with IJD.