Does disease activity at the start of biologic therapy influence health care costs in patients with RA?

Abstract

To investigate whether disease activity at baseline influences health care costs in patients with RA initiating biologic treatment. In the Swedish Biologics Register, we identified patients with RA with baseline 28-joint DAS (DAS28) recorded and starting their first biologic in 2007-11 [n = 1638 with moderate disease activity (DAS28 3.2-5.1) and n = 1870 with high disease activity (DAS28 > 5.1)]. Data on inpatient and outpatient care and prescription drugs were retrieved from nationwide registers. Mean cost differences were estimated adjusted for age, sex and costs the year before treatment start. Patients with high (vs moderate) disease activity were older (60 vs 56 years; P < 0.001), but did not differ in sex distribution (75 vs 74% women; P = 0.99) or disease duration (10 vs 10 years; P = 0.13). The year after initiation of biologics, patients with high (vs moderate) baseline disease activity accumulated 9% higher health care costs, but the difference was not statistically significant after adjustment [€19,333 vs €17,810; adjusted difference €870 (95% CI -2, 1742)]. In the subgroup of patients with up to 4 years of follow-up data, decreasing costs were observed over the follow-up time, but no difference was found between patients with high compared with moderate baseline disease activity [€13,704 vs €12,349; adjusted difference 878 (95% CI -364, 2120)]. Irrespective of baseline disease activity, health care costs were approximately three times higher the year after initiation of biologics than the year before due to increased drug costs. Over up to 4 years of follow-up, no difference in health care costs was found after adjustment in patients starting their first biologic treatment with high vs moderate baseline disease activity.