Aspects of disability in early rheumatoid arthritis : a five-year follow-up in the Swedish TIRA project

Abstract: Rheumatoid arthritis (RA) is a progressive disease, often leading to disability. Because the disease course develops rapidly during the first years after diagnosis, more knowledge is needed about the early disease course to minimize later disability. This thesis describes the course of disability in early RA such as hand function, pain intensity, activity limitation and sick leave. In addition, this thesis compares disability between women and men and compares disability between RA patients and referents. This thesis is primarily based on data from the 320 patients that were included in the multi-centre project in Sweden called ‘Early interventions in rheumatoid arthritis’ (TIRA). A wide range of outcome variables was registered between 1996 and 2006 during regular follow-ups from time for diagnosis through the eight-year follow-up. Outcome regarding disease activity and disability of RA patients still remaining in TIRA at the three and five year follow-up respectively are used in this thesis. Data concerning sick leave were obtained for the patients during six years (1993-2001) – three years before and three years after diagnosis. Referents were included in two of the studies. Data regarding disability in referents were obtained according to hand function and activity limitation using the Health Assessment Questionnaire (HAQ). Data for sick leave were obtained for six years in referents, for the same period as the RA patients.For most variables, disability in RA was most pronounced at time of diagnosis but before intervention started. Disability was then reduced already at the 3-month follow-up and thereafter affected but stable during the following five years. The exception was participation, reflected by sick leave, a variable that was stable from inclusion to three years from diagnosis. Activity limitation, pain intensity and sick leave in RA that represents different aspects of disability were explained by other aspects of disability and contextual factors rather than by disease activity. RA affects women and men differently in some aspects. Women had more severe course of activity limitations than men according to HAQ. Men were more affected than women in range of motion, although the differences were small in a clinical perspective. However, pain intensity and frequency of sick leave did not differ between women and men. Patients with RA have pronounced disability in relation to referents although several variables improve soon after diagnosis. This discrepancy refers to hand function as well as activity limitations and sick leave. The frequency of sick leave increased during the year before diagnosis in relation to referents and was thereafter high compared to sick leave in referents.