Economic impact of biologic utilization patterns in patients with psoriatic arthritis

The aim of the study is to examine the frequency and costs associated with above-label dosing of biologics in patients with psoriatic arthritis (PsA). MarketScan identified adults with ≥1 International Classification of Diseases, Clinical Modification diagnosis for PsA and ≥1 pharmacy claim for biologics of interest between January 1, 2011 and December 31, 2013. The first biologic claim was the index date with a 1-year follow-up period and three additional months to confirm continuous biologic use. Exclusion criteria included switching to a different biologic or diagnosis with another autoimmune disease. During the follow-up period, duration was stratified into three groups: <30, 30-179, and ≥180 days of above-label dosing (>10% of the labeled dose). One-tailed t test was conducted to examine the impact of above-label duration on healthcare costs. We identified 4245 PsA patients receiving etanercept (n = 2342), adalimumab (n = 1788), and golimumab (n = 115). Above-label dosing of <30 days (85% adalimumab, 90.4% etanercept, and 95.7% golimumab) and ≥180 days (9.6% adalimumab, 4.1% etanercept, and 2.6% golimumab) was observed. All-cause total healthcare costs for <30 days of above-label use (etanercept $30,625, adalimumab $31,620, and golimumab $37,224), 30-179 days (etanercept $35,602, adalimumab $38,915, and golimumab $64,349), and ≥180 days (etanercept $55,349, adalimumab $54,176, and golimumab $47,993) were reported. Longer above-label duration (30-179 versus <30 days, ≥180 versus 30-179 and ≥180 days) with etanercept or adalimumab was significantly associated with higher mean increased total all-cause healthcare, PsA-specific healthcare, and biologic costs (p < 0.05). Above-label use of anti-TNF biologics does occur and is associated with significantly increased healthcare costs.