Register-Based Evaluation of Relative Effectiveness of New Therapies: Biologics Versus Conventional Agents in Treatment of Psoriasis in Sweden.

Background: The Swedish National Register for Systemic Treatment of Psoriasis (PsoReg) was established in 2006. This article analyzes the implementation phase of biologics in the treatment of moderate to severe psoriasis in Sweden in the period 2006-2012. Clinical studies have shown efficacy of biologic agents in psoriasis, but their relative effectiveness in real-world clinical practice has rarely been studied.

Objective: To estimate the incremental changes in clinical health-related quality-of-life measures in patients receiving biologics versus conventional systemic agents.

Methods: Patients fulfilling the clinical criteria for moderate to severe psoriasis were included. Average treatment effects were estimated from longitudinal data as incremental changes in: (1) the Psoriasis Area and Severity Index (PASI) score, (2) the Dermatology Life Quality Index (DLQI) score, and (3) the EQ-5D score, by matching patients switching to biologics with patients remaining on conventional systemic agents.

Results: The study included 239 biologic-treated patients and 378 conventionally treated patients. The matched patient groups were essentially equivalent in terms of important patient characteristics. The average treatment effects of biologics versus conventional systemic agents were 2.2 for PASI, 3.5 for DLQI, and 0.11 for EQ-5D. The estimated incremental benefits of biologics for the subgroup of patients not responding to their conventional systemic agent were even greater.

Conclusion: Register-based research complements knowledge from randomized controlled trials regarding relative effectiveness in clinical practice. This information can be used to support health care decision making. This research suggests that there is both under- and overtreatment with biologics in Swedish clinical practice. Reallocation of biologics to more severe cases of psoriasis could improve overall health in the total patient population.