A retrospective cohort study of the impact of biologic therapy initiation on medical resource use and costs in patients with moderate to severe psoriasis

Abstract

Biologic therapy has become established as an important treatment option in patients with severe psoriasis, but is significantly more expensive in terms of drug costs than traditional treatment options. Relatively little is known about the total healthcare cost of treating severe psoriasis in daily clinical practice and what the budgetary impacts of such high-cost drugs are when compared with standard systemic therapy. To describe the impact of biologic therapy introduction on the use of medical resources, costs and where available, outcomes in patients with moderate to severe psoriasis. Data were extracted from case notes of a sequential patient cohort with psoriasis attending a tertiary referral severe psoriasis service and initiated on biologics (adalimumab, efalizumab, etanercept or infliximab) for treatment of their psoriasis. Data on hospital resource use (inpatient, outpatient, day ward, accident and emergency visits and phototherapy sessions) and drug usage (systemic nonbiologic and biologic psoriasis therapies and supportive drugs) were collected for 12 months prior to, and at least 6 months following initiation of biologic therapy. Outcome was measured using the Psoriasis Area and Severity Index (PASI). Differences in resource use and associated costs and outcomes, between 12 months before and after initiation of biologic therapy, were tested using Wilcoxon paired sign tests for continuous data and the McNemar test for categorical data. Confidence intervals (CI) around treatment costs were constructed using a 5000-sample bootstrap analysis. The primary analysis population comprised 76 patients completing 12 months of biologic therapy: 71% males; mean age at time of study 47·3 years (range 23-74); mean duration of psoriasis 24·7 years (range 5·3-45·5). Significant reductions (P < 0·05) in the year following initiation of biologic therapy were observed for all hospital resource use categories, with mean annual costs reduced by £1682 (95% CI -3182 to -182·2; P = 0·05). Mean annual drug costs increased by £9456 (95% CI 8732-10,182; P < 0·001). Mean PASI fell by 8·9 points from 18·7 to 9·8 (95% CI -10·8 to -7·1; P < 0·001). Total healthcare costs associated with treatment of severe psoriasis with biologic therapy are significantly greater than with traditional systemic therapy. However, some of these are offset by substantial reductions in the number and length of hospital admissions and use of photo- and systemic therapy, and result in significantly improved patient outcome (as inferred by improvement in PASI).