gms | German Medical Science

Background: Rheumatoid arthritis (RA) is a chronic inflammatory disorder characterized by chronic inflammation of joints. In Germany, the prevalence of RA is about 0.5–1.0% of adults. Disease-modifying antirheumatic drugs (DMARDs) is the most common first-line therapy of RA. According to treatment recommendations, the administration of biotechnologically produced DMARDs (biologicals) is indicated as second-line therapy for RA patients in whom prior therapy had no desired effect. Little is known about the specific prescribing behavior of rheumatologists in Germany with regard to bDMARDs therapy. The aims of this study were to assess how many RA patients received biologicals after therapy initiation of DMARD and which factors influenced whether a patient did or did not receive biological therapy.

Methods: This retrospective study used data from the IMS Health LRx Germany database which accesses nationwide pharmacy data centres processing prescriptions of all German patients with statutory health insurance for reimbursement purposes. The IMS® LRx database actually contains roughly 60% of all prescriptions issued nationwide.

The study included male and female adult (= 18 years old) patients who had initiated therapy with a DMARD at a rheumatologist between January 1^st, 2009 and December 31^st, 2013. The date of first prescription was defined as the index date. The minimum pre-index history was 12 months.

The time until first prescription for a biological over five years was noted as the main outcome measure of this study. Kaplan-Meier curves were plotted to determine the time elapsed from the first DMARD prescription until a biological prescription. These were also used to assess possible differences in time to biological prescription in female and male patients and different age groups. Cox regression analyses were performed to establish the link between biological therapy initiation within five years years and predefined impact variables, such as age and gender.

Results: Data from a total of 137,673 patients were available for the analyses. The mean age was 57.8 (SD: 15.0) years; 68.3% were female. 62% were treated with methotrexate as initial DMARD substance, 13% with sulfasalazine, 12% with hydroxychloroquine, 10% with leflunomide and 2% with azathioprine.

20.7% were initiated on biologicals within five years of the initial DMARD prescription. Male patients received biological therapy more often than female patients (22.1% versus 20.0%, p<0.01). Moreover, the likelihood of biological therapy decreased with age and was most likely in patients under 40 years old (33.3%) and least likely in patients aged over 80 years (10.3%). The associations of age and gender with use of biologicals were also assessed using multivariate Cox regression models. Age decreased the odds of biological prescription by 3% per year and male sex was related to a 10% higher chance of biological use.

Discussion/Conclusion: In conclusion, only 21% of study patients in German rheumatologist care practices were treated with biologicals. Biological prescriptions were associated with younger age and male gender. Missing diagnosis information is the main limitation of this study. Further studies are needed to understand the medical care of RA patients in Germany.

Implications for practice: Due to the imminent introduction of biosimilars following the expiry of patents on biologicals, it is important to gain a better insight into prescribing behaviour in this market to be able to predict the requirement for these therapeutic agents.