Health Care Utilization and Cost Associated with Biologic Treatment Patterns Among Patients with Moderate to Severe Psoriasis: Analyses from a Large US Claims Database

BACKGROUND: Discontinuation or switching of biologic treatment among patients with psoriasis imposes a great economic burden. OBJECTIVE: To assess the health care utilization and costs associated with nonswitchers, switchers, and discontinuers of biologics among patients with moderate to severe psoriasis. METHODS: Patients aged >= 18 years with >= 1 pharmacy claim for a biologic (adalimumab, etanercept, infliximab, and ustekinumab) between January 1, 2012, and June 30, 2015 (identification period), were identified in the Truven Health Analytics MarketScan Commercial and Medicare Supplemental databases. At the time of biologic initiation (index date), eligible patients were continuously enrolled with medical and pharmacy claims for >= 1 year before (baseline period) and >= 1 year after the index date (follow-up period). Patients had >= 1 psoriasis diagnosis and had no pharmacy claims for the index biologic during the baseline period. Patients were categorized into 3 mutually exclusive groups based on their biologic treatment pattern during the 1-year follow-up period: nonswitchers (patients who remained on their index biologic), switchers (patients who had a prescription for a biologic therapy other than their index biologic), and discontinuers (patients who had gaps in prescription claims [> 90 days for adalimumab, infliximab, and etanercept; > 120 days for ustekinumab]). Descriptive analyses were used to summarize baseline patient demographics, clinical characteristics, resource utilization, and health care costs (inflated to 2016 costs) across the 3 groups. Adjusted health care resource utilization and costs during the 1-year follow-up were estimated, controlling for age, sex, geographic region, insurance plan type, index drug, index year, Charlson Comorbidity Index score, resource utilization, total health care costs, and nonbiologic medications during the baseline period. RESULTS: Of the 8,710 patients with psoriasis included in the study, 5,000 (57.4%) were categorized as nonswitchers, 1,001 (11.5%) as switchers, and 2,709 (31.1%) as discontinuers. Emergency department and inpatient visits, respectively, were more common among switchers (adjusted incidence rate ratio [95% CI]: 1.10 [0.93-1.30] and 1.13 [0.84-1.53]) and discontinuers (1.50 [1.34-1.63] and 2.05 [1.70-2.48]) than among nonswitchers. Compared with nonswitchers, switchers had higher adjusted mean total health care costs (mean difference [95% CI]: $10,120 [$8,235-$12,033]), which were driven by increased prescription costs ($8,988 [$7,535-$10,610]) and medical costs ($2,746 [$1,090-$4,677]). Conversely, the adjusted mean total health care cost for discontinuers was lower than that for nonswitchers (mean difference [95% CI]: -$18,611 [-$20,254, -$17,025]) due to reduced prescription costs (-$20,486 [-$21,319, -$19,636]); however, discontinuers had a higher mean medical cost ($3,729 [$1,970-$5,527]). CONCLUSIONS: Switching or discontinuing biologics resulted in higher health care utilization and increased medical costs than remaining on the same biologic. These updated findings highlight the clinical and economic effects of discontinuing or switching biologic therapies in patients with psoriasis in clinical practice and may inform treatment and/or formulary decision making. Copyright (C) 2019, Academy of Managed Care Pharmacy. All rights reserved.