Background Long term disease impact on physical functioning in the most affected patients with RA is not well described. Impaired function and inability to be physically active are associated features and it is well known that people with RA are less physically active compared with the general population.
Objectives To study predictive variables for a worse outcome in physical function and physical activity measures in a long time follow-up study.
Methods Between 1992 and 2005 all patients with newly diagnosed RA according to criteria of the American College of Rheumatology were asked to participate in the BARFOT study, a collaboration between six Swedish rheumatology departments. In 2010 all patients (n=2114) included in the study received a follow-up questionnaire 5-18 years after disease onset. Using logistic regression analyses, the dependent variables physical function (dichotomized by their mean value) were measured with the HAQ (scores 0 to 3, best to worst), the RAOS (Rheumatoid Arthritis Outcome Score) subscales ADL and sport/rec (0-100, worst to best) and meeting vs. not meeting WHO recommendations of physical activity (WHOrec) for a healthy life style (moderate intensity ≥150 min/week or higher intensity for at least 30 minutes 2-3 times/week). Possible predictive variables at baseline were function (HAQ and SOFI, Signals of Functional Impairment, 0-44, best to worse), disease activity (CRP, swollen and tender joints), pain (VAS 0-100, best to worst) and age. We also controlled for sex and disease duration in 2010.
Results Questionnaire response was 72% (n=1525), mean (m) age 65 years (SD 14), m follow-up time 9 years (SD 3.7) and 70% (n=1069) were women.
At inclusion the patients reported a disease duration of m 8 (SD 9) months, HAQ m 1.0 (SD 0.6), VAS pain m 46 (SD24), SOFI m 8.0 (SD6.0). Disease activity was CRP m 30.2 (SD 35.9), swollen joints m 10.2 (SD 5.7) and tender joints m 8.2 (SD 6.2).
In the 2010 survey, time from inclusion was m 9.4 (SD 3.8) years, the HAQ m 0.6 (SD 0.6), and VAS pain m 35.5 (SD 25.6) had decreased (p<0.001). RAOS ADL was m 71,1 (SD 22.0), RAOS sport/rec m 40.0 (SD 30.0) and 61% (N=894) met the WHOrec.
Worse scores in the HAQ, VAS pain and SOFI at baseline increased the risk for worse physical function in the 2010 survey measured with the HAQ (VAS pain OR 1.02, SOFI OR 1.09 and HAQ OR 3.98, p<0.000), the RAOS ADL scale (VAS pain OR 1.02, SOFI OR 1,09 and HAQ OR 2.66, p<0.000) and the RAOS sport/rec scale (VAS pain OR 1.02, SOFI OR 1.11 and HAQ OR 2.57, p<0.000). Being a woman, higher age at inclusion and longer disease duration at follow-up also predicted a worse function in the HAQ and both RAOS subscales while none of the studied variables could predict who did/did not meet the WHOrec in 2010.
Conclusions Worse physical function and worse pain at disease onset can predict a worse physical function several years later. However, it does not predict the amount of physical activity actually being performed. It is of importance to already at disease onset recognize patients with impaired function and higher pain levels who are in need of multidisciplinary treatments. It is also important to early in the disease recommend a healthy life style according to the WHOrec since measures of function and being physically active are different entities.
Disclosure of Interest None Declared