Is the Non-Operative Management of Appendicitis Cost Effective? A Markov-Based Analysis of the Comparison of Drugs and Appendectomy (CODA) Trial

Abstract

Non-operative management (NOM) has emerged as a viable alternative to appendectomy for acute uncomplicated appendicitis. This development has been supported by multiple randomized control trials; however, it is not fully known whether non-operative management (either as an inpatient or outpatient) is cost-effective compared to appendectomy. This work utilizes a previous microcosted analysis of the CODA trial, and combines this with transition probabilities and utilities also derived from the CODA trial. It applies these parameters within a 2-, 5-, and 10- year time horizon Markov model that examines the impact of upfront costs and disutility after NOM or surgery as well as the long term risk of delayed appendectomy after NOM. The primary model suggests that OP NOM is cost effective compared to IP NOM or surgery, while IP NOM is only cost effective compared to surgery at short (2-year) time horizons. When examined probabilistically at both the 5- and 10-year time horizon, OP NOM has by far the highest probability of being cost effective. Limitations of this thesis are a limited modelling of long-term complications beyond delayed failure, and that it may not capture patient heterogeneity that may shift cost or utility outcomes. Future work will seek to capture the heterogeneity of outcomes after both strategies, and model populations not well captured by the CODA trial.