Improved Cardiovascular Health for Patients With Inflammatory Joint Diseases

The study is a two-armed randomized controlled trial (RCT). Patients aged 18-70 years presenting with inflammatory joint disease at the Preventive Cardio-Rheuma clinic at Diakonhjemmet hospital (Oslo) will be included if eligible for the study. Succeeding baseline testing, participants are randomized to either experimental group (high-intensity exercise-HIIT) or control group (usual care). The research questions are: 1. Is a 12-week HIIT program effective on VO2peak, inflammatory markers and risk of cardiovascular disease in patients with inflammatory joint disease and what is the association between VO2peak and disease-specific and cardiovascular disease-related variables? 2. Is a non-exercise cardio-respiratory fitness algorithm (eCRF) valid in determining longitudinal change in VO2peak in patients with inflammatory joint disease? 3. How feasible is a HIIT intervention in primary care in patients with inflammatory joint disease in terms of adherence and fidelity to the exercise program? The primary analysis will be a between group comparison of VO2peak levels. This will be carried out according to the intention-to-treat principle, and done by the analysis of covariance (ANCOVA), adjusting for VO2peak values at baseline along with stratification factors used in the randomization. Secondary analyses will include between group comparisons on secondary endpoints, as well as comparisons in the per protocol population. No adjustment for multiple testing will be done. The association between VO2peak and changes in inflammatory markers, disease activity and CVD risk will be assessed using multiple regression. The validity of eCRF models to accurately detect longitudinal change in VO2peak from baseline to 3-month and 6-month follow-up will be assessed with Pearson or Spearman correlation by comparing VO2peak derived from a cardiopulmonary exercise test to eCRF. The feasibility of a HIIT program and adherence will be examined with descriptive statistics. Adherence to the prescribed HIIT intervention will be recorded by attendance to exercise sessions. Quality of treatment delivery will be quantified as the number of exercise sessions complying with the planned exercise intensity and number of exercise sessions requiring dose modifications such as lower exercise intensity or early session termination. At the 3-month timepoint, an electronic questionnaire will be distributed to patients in the HIIT group. Questions regarding feasibility and implementation fidelity will address patients' acceptability and satisfaction with the HIIT program. The ExeHeart study will also include semi-structured interviews, targeting physiotherapists in charge of supervising the exercise sessions and 5-7 patients in the intervention group. The interviews will explore barriers and facilitators in exercise adherence, experience with the protocol and perceived effects of exercise.