Comparing methods for handling missing cost and quality of life data in the Early Endovenous Ablation in Venous Ulceration trial Diop Wayal, Modou Epstein, David Mark Longitudinal missing outcome Repeated measure Mixed model Fixed effect Multiple imputation Complete-case-analysis Bayesian parametric approach Cost-effectiveness analysis This study was funded by the National Institute for Health Research (NIHR HTA) Programme (EVRA, project number 11/129/197) and European Union's Horizon 2020 research under Grant agreement 733203. Objectives: This study compares methods for handling missing data to conduct cost-effectiveness analysis in the context of a clinical study. Methods: Patients in the Early Endovenous Ablation in Venous Ulceration (EVRA) trial had between 1 year and 5.5 years (median 3 years) of follow-up under early or deferred endovenous ablation. This study compares completecase- analysis (CCA), multiple imputation using linear regression (MILR) and using predictive mean matching (MIPMM), Bayesian parametric approach using the R package missingHE (BPA), repeated measures fixed effect (RMFE) and repeated measures mixed model (RMM). The outcomes were total mean costs and total mean quality-adjusted life years (QALYs) at different time horizons (1 year, 3 years and 5 years). Results: All methods found no statistically significant difference in cost at the 5% level in all time horizons, and all methods found statistically significantly greater mean QALY at year 1. By year 3, only BPA showed a statistically significant difference in QALY between treatments. Standard errors differed substantially between the methods employed. Conclusion: CCA can be biased if data are MAR and is wasteful of the data. Hence the results for CCA are likely to be inaccurate. Other methods coincide in suggesting that early intervention is cost-effective at a threshold of £30,000 per QALY 1, 3 and 5 years. However, the variation in the results across the methods does generate some additional methodological uncertainty, underlining the importance of conducting sensitivity analyses using alternative approaches. 2022-05-04T12:24:48Z 2022-05-04T12:24:48Z 2022-04-07 journal article Diop, M., Epstein, D. Comparing methods for handling missing cost and quality of life data in the Early Endovenous Ablation in Venous Ulceration trial. Cost Eff Resour Alloc 20, 18 (2022). [https://doi.org/10.1186/s12962-022-00351-6] http://hdl.handle.net/10481/74699 10.1186/s12962-022-00351-6 eng info:eu-repo/grantAgreement/EC/H2020/733203 http://creativecommons.org/licenses/by/3.0/es/ open access Atribución 3.0 España BMC