Article

Expert Prior Elicitation and Bayesian Analysis of the Mycotic Ulcer Treatment Trial I

F.I. Proctor Foundation, University of California, San Francisco, CA, United States.
Investigative ophthalmology & visual science (Impact Factor: 3.66). 05/2013; 54(6). DOI: 10.1167/iovs.13-11716
Source: PubMed

ABSTRACT PURPOSE: To perform a Bayesian analysis of the Mycotic Ulcer Treatment Trial I (MUTT I) using expert opinion as a prior belief. METHODS: MUTT I was a randomized clinical trial comparing topical natamycin or voriconazole for treating filamentous fungal keratitis. A questionnaire elicited expert opinion on the best treatment of fungal keratitis before MUTT I results were available. A Bayesian analysis was performed using the questionnaire data as a prior belief and the MUTT I primary outcome (3-month visual acuity) by frequentist analysis as a likelihood. RESULTS: Corneal experts had a 41.1% prior belief that natamycin improved 3-month visual acuity compared to voriconazole. The Bayesian analysis found a 98.4% belief for natamycin treatment compared to voriconazole treatment for filamentous cases as a group (mean improvement 1.1 Snellen lines, 95% credible interval 0.1-2.1). The Bayesian analysis estimated a smaller treatment effect than the MUTT I frequentist analysis result of 1.8-line improvement with natamycin versus voriconazole (95% confidence interval 0.5-3.0, P=0.006). For Fusarium cases, the posterior demonstrated a 99.7% belief for natamycin treatment, while non-Fusarium cases had a 57.3% belief. CONCLUSIONS: The Bayesian analysis suggests that natamycin is superior to voriconazole when filamentous cases are analyzed as a group. Subgroup analysis of Fusarium cases found improvement with natamycin compared to voriconazole, while there was almost no difference between treatments for non-Fusarium cases. These results were consistent with, though smaller in effect size than, the MUTT I primary outcome by frequentist analysis. The accordance between analyses further validates the trial results.

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