A semi-Markov model comparing the lifetime cost-effectiveness of mesh prophylaxis to prevent parastomal hernia in patients undergoing end colostomy creation for rectal cancer

Abstract

AIM: Parastomal hernia (PSH) is a common problem following colostomy. Using prophylactic mesh during end colostomy creation may reduce PSH incidence, but concerns exist regarding the optimal type of mesh, potential long-term complications, and cost-effectiveness of its use. We evaluated the cost-effectiveness of mesh prophylaxis to prevent PSH in patients undergoing end colostomy creation for rectal cancer. METHODS: We developed a decision-analytical model, stratified by rectal cancer stages I-IV, to estimate the lifetime costs, quality-adjusted life-years (QALYs) and net monetary benefits (NMBs) of synthetic, biologic and no mesh from a UK NHS perspective. We pooled the mesh-related relative risks of PSH from 13 randomised controlled trials (RCTs) and superimposed these on the baseline (no mesh) risk from a population-based cohort. Uncertainty was assessed in sensitivity analyses. RESULTS: Synthetic mesh was less costly and more effective than biologic and no mesh to prevent PSH for all rectal cancer stages. At the willingness-to-pay threshold of £20,000/QALY, the incremental NMBs (95% CI) ranged between £3,412 (£3,384 to £3,439) (stage I) and £1,305 (£1,293 to £1,316) (stage IV) for synthetic versus no mesh, and £2,449 (£2,371 to £2,526) (stage I) and £1,784 (£1,753 to £1,815) (stage IV) for synthetic versus biologic mesh. Synthetic mesh was more cost-effective than no mesh unless the relative risk of PSH was ≥0.97 for stages I-III and ≥0.94 for stage IV. CONCLUSIONS: Synthetic mesh was the most cost-effective strategy to prevent the formation of PSH in patients after end colostomy for any rectal cancer stage; however, conclusions are dependent on which subset of RCTs are considered to provide the most robust evidence.