Ciclosporin compared with prednisolone therapy for patients with pyoderma gangrenosum: cost‐effectiveness analysis of the STOP GAP trial

BACKGROUND: Pyoderma gangrenosum (PG) is a painful, ulcerating skin disease with poor evidence for management. Prednisolone and ciclosporin are the most commonly used treatments, although not previously compared within a randomized controlled trial (RCT). OBJECTIVES: To compare the cost‐effectiveness of ciclosporin and prednisolone‐initiated treatment for patients with PG. METHODS: Quality of life (QoL, EuroQoL five dimensions three level questionnaire, EQ‐5D‐3L) and resource data were collected as part of the STOP GAP trial: a multicentre, parallel‐group, observer‐blind RCT. Within‐trial analysis used bivariate regression of costs and quality‐adjusted life years (QALYs), with multiple imputation of missing data, informing a probabilistic assessment of incremental treatment cost‐effectiveness from a health service perspective. RESULTS: In the base case analysis, when compared with prednisolone, ciclosporin was cost‐effective due to a reduction in costs [net cost: −£1160; 95% confidence interval (CI) −2991 to 672] and improvement in QoL (net QALYs: 0·055; 95% CI 0·018–0·093). However, this finding appears driven by a minority of patients with large lesions (≥ 20 cm(2)) (net cost: −£5310; 95% CI −9729 to −891; net QALYs: 0·077; 95% CI 0·004–0·151). The incremental cost‐effectiveness of ciclosporin for the majority of patients with smaller lesions was £23 374/QALY, although the estimate is imprecise: the probability of being cost‐effective at a willingness‐to‐pay of £20 000/QALY was 43%. CONCLUSIONS: Consistent with the clinical findings of the STOP GAP trial, patients with small lesions should receive treatment guided by the side‐effect profiles of the drugs and patient preference – neither strategy is clearly a preferred use of National Health Service resources. However, ciclosporin‐initiated treatment may be more cost‐effective for patients with large lesions.