Health-enhancing physical activity in rheumatoid arthritis : prevalence, intervention and assessment

Abstract

Background and Aim: Rheumatoid arthritis (RA) is associated with poor health and functioning, and increased risk of cardiovasculardisease. Health-enhancing physical activity (HEPA), defined in the present work as “a minimum of 30 minutes of at least moderately intense daily physical activity, whereof at least twice weekly circuit training sessions including both aerobic and muscular strength training”, is a key component in the life-long management of RA as it reduces the risk of disability and comorbidity. The overall aim of the present work was to study the prevalence of HEPA and its correlates in people with RA, to describe the selection procedure for a one-year HEPA intervention, to explore the one-year adherence and response to the intervention program, and to examine the criterion validity of two assessment methods for estimation of aerobic capacity in people with RA.

Methods: Studies I and II, with cross-sectional designs, included 3,152 participants, mean age 56 years (SD 11.2). They were assessed with data retrieved from the Swedish Rheumatology Quality Registers (SRQ) and postal questionnaires. Study III is a study protocol describing a one-year HEPA intervention. Study IV, with a prospective longitudinal cohort design, included 220 participants mean age 59 years (SD 8.9), assessed with data from SRQ, questionnaires and physical performance tests before and after the one-year intervention. The HEPA program was performed in the participants’ daily environment and at public gyms. Physiotherapists introduced daily physical activity and circuit training, and coached support groups applying behavioral change techniques. Twenty seven participants, mean age 62 years (SD 8.1) were recruited for Study V with a methodological design. The submaximal Fox-walk test and the Åstrand cycle ergometry test for estimation of maximal oxygen uptake (VO2max) were validated against a maximal cycle ergometry test.

Results: A minority (11%) of the large, well-defined sample of people with RA reached recommended levels of maintained (>6 months) HEPA, while 69% reported HEPA the past week. Twenty-two percent of the variation in maintained HEPA was explained, and the most salient and consistent explanatory factors were exercise self-efficacy, social support and outcome expectations related to physical activity (Study I). Only 8% of the targeted sample for the one-year HEPA program was reached. Factors other than those related to the disease, i.e. sociodemographic and psychosocial factors mainly determined participation (Study II). High retention (88%) and reasonable attendance (50%) to the one-year HEPA program were observed. While no participant reported maintained HEPA at baseline, 37% did so after one year. A number of self-reported health outcomes improved as did physical capacity tests. Relations between adherence to the three main HEPA program components and response were not clear-cut (Study IV). The self-administered Fox-walk test overestimated aerobic capacity substantially while the Åstrand test displayed excellent criterion validity in a sample with fairly fit individuals (Study V).

In conclusion, the results indicate a need for improved HEPA promotion, suggests that outsourced HEPA programs might be suitable for subgroups of persons with RA, and provides validity information on two submaximal tests of aerobic capacity.