The impact of non-persistence on the direct and indirect costs in patients treated with subcutaneous tumour necrosis factor-alpha inhibitors in Germany

Objective. The goal of the present study was to estimate the treatment costs in immune-mediated rheumatic disease patients initiating treatment with an s.c. biologic agent based on treatment persistence. Methods. This is a retrospective cohort study based on the German statutory health insurance funds database. Patients 518 years of age with a diagnosis of AS, PsA or RA treated with s.c. TNF-alpha inhibitors (TNFis) were included. Persistence was estimated as the duration of time from s.c. TNFi therapy initiation to discontinuation, which was defined as at least 60 days without therapy. We performed 1:1 matching based on a propensity score that was constructed as the conditional probability of being persistent as a function of age, gender, index year, physician specialty and Charlson comorbidity index. Finally, the cost differences between the matched pairs were estimated using the Wilcoxon test. Results. After 1:1 matching, 678 persistent and 678 non-persistent patients were available for cost analyses. Using a 2-year time period, the costs for office-based visits per patient were E2319 in the persistent cohort compared with E3094 in the non-persistent cohort (P<0.001). Co-medication costs were E2828 in the persistent cohort compared with E5498 in the non-persistent cohort, hospitalization costs were E3551 in the persistent cohort compared with E5890 in the non-persistent cohort and sick leave costs were E717 in the persistent cohort compared with E1241 in the non-persistent cohort (all P<0.001). Conclusion. The results of this study indicate that persistence with s.c. TNFi treatment can be associated with several cost offsets for immune-mediated rheumatic disease patients.