An economic evaluation comparing concomitant oral and topical mesalazine versus oral mesalazine alone in mild-to-moderately active ulcerative colitis based on results from randomised controlled trial

Abstract

Introduction A previous randomised controlled trial has demonstrated that oral plus topical mesalazine enema is more effective than oral mesalazine alone for achieving clinical remission in mild-to-moderately active extensive ulcerative colitis (UC). To evaluate whether this strategy is cost-effective we conducted an economic evaluation comparing 1 g topical mesalazine in combination with 4 g oral mesalazine compared to 4 g mesalazine monotherapy in mild-to-moderately active UC. Methods The economic evaluation was based on the ability to achieve remission using changes from baseline in the ulcerative colitis disease activity instrument (UCDAI). A cost-utility analysis was used where the main outcome was quality-adjusted life years to reflect improved quality of life associated with achieving remission compared with active disease. A simulated Markov model with five health states was constructed to model cost and outcome changes over time: (1) active UC; (2) mesalazine-refractory active UC; (3) steroid-refractory active UC; (4) infliximab-responsive active UC; and (5) remission. To reflect parameter uncertainty in the cost-effectiveness analysis probabilistic sensitivity analysis (PSA) was conducted by varying relevant clinical parameters. Results Average treatment costs required to transition a patient from active UC to remission using oral and topical mesalazine compared with oral alone were £1812 and £2390, respectively. Improved remission rates attributed to oral and topical mesalazine resulted in moderate improvements in quality-adjusted life years (QALYs) compared to oral mesalazine alone. Disaggregation of medical costs indicated that medical consultations and diagnostic costs were similar for both treatment arms. An abbreviated analysis which considered costs up to steroid-refractory patients in subacute UC indicated that combination therapy offered a cost-savings of £285 over 16 weeks of therapy compared with monotherapy. Conclusions The results indicate that the addition of 1 g topical mesalazine results in significant cost-savings and moderate quality of life improvements. We have also shown that irrespective of which treatment modality is used in steroid-refractory patients (eg, infliximab, azathioprine, ciclosporine) that topical mesalazine is cost-saving.