Background Treatment with biological DMARDs (bDMARDs) in rheumatoid arthritis (RA) is increasing. There is a selection of patients with less comorbidity in randomized controlled trials assessing the effects of bDMARDs. If characteristics differ between RA patients on bDMARDs vs not on bDMARDs in routine care has not been extensively studied.
Objectives The aim of this study was to investigate the use of bDMARDs in patients with RA in western Sweden and if characteristics and comorbidity differed between patients receiving bDMARDs and patients who did not in cross-sectional analysis in a population based setting.
Methods Patients, ≥18 years, diagnosed with RA, attending a specialist care unit at least once 2009 through 2010, were identified in the regional health care database, Vega. Cumulative frequencies for in- and outpatient visits with predefined comorbidities were extracted from Vega for the period 2006 through 2010. Patients on bDMARDs 31 December 2010 were identified in the national Swedish biologics register, ARTIS and by linkage also in Vega. Data from ARTIS were validated against the medical records. Descriptive, comparative and multiple logistic regression analysis were used to identify factors significantly associated with biological treatment or not.
Results A total of 7712 patients with RA were identified out of which 1137 (14.7%) were on bDMARDs. Another 390 patients were identified having bDMARDs, but validation process revealed that they had stopped or planned to begin a bDMARD and were excluded from further analyses. In all, 60% of the patients on bDMARDs were treated with their first bDMARDs and 28% their second. The three most frequently used bDMARDs were Infliximab (36%), etanercept (28%) and rituximab (16%). The patients on bDMARDs had a disease duration of (mean ± SD) 16±11 years, a disease activity score of 28 joints (DAS28) of 3.0±1.3, and had been treated with their present bDMARDs for 41±33 months. Characteristics of the patients are shown in the table. Patients treated with bDMARDs had compared to those not treated lower age and lower occurrence of cerebrovascular, congestive heart, chronic respiratory disease, depression and malignancy in multiple logistic regression models, whereas the occurrence of infectious disease was higher. Sex, presence of diabetes and ischemic heart disease were not significantly different between the two groups.
Conclusions In western Sweden, 14.7% of RA patients were on bDMARDs 31 December 2010. Those treated with bDMARDs compared to those not were younger and had overall lower occurrences for comorbidities, with the exception for documented infections supporting the overall safety in the manner bDMARDs are used in the population.
Disclosure of Interest None declared