Cost-utility analysis of prophylactic laser peripheral iridotomy for primary angle closure suspects

Abstract

Purpose: To assess the cost-utility of prophylactic laser peripheral iridotomy (LPI) for primary angle closure (PAC) suspects (PACS).

Design: Economic evaluation.

Methods: Our Markov model randomized PACS eyes to LPI or observation for 40 one-year cycles (100,000 iterations per strategy). Each cycle, an eye remained in its current health state, advanced linearly through PAC, mild, moderate, severe, and end-stage PAC glaucoma (PACG), or died. Transition rates were derived from the literature including the Zhongshan Angle Closure Prevention (ZAP) trial and the Singapore Asymptomatic Narrow Angles Laser Iridotomy Study (ANA-LIS). Eyes with acute-angle closure advanced to either PAC or directly to various PACG severities. A tracker monitored accumulated perimetric decibel reduction to progress PACG through increasing severities, with an annual probability of either stable or severity-dependent perimetry loss. We set a willingness to pay of an incremental cost-effectiveness ratio (ICER) <$50,000/quality-adjusted life years.

Results: At age 50, LPI was cost-saving using ZAP data and cost-effective using ANA-LIS data. The ZAP iterations became cost-effective from the societal perspective when the model started at age 55 and third-party perspective at age 70. LPI was no longer cost-effective from the societal perspective using ANA-LIS data at age 80 or from the societal perspective using ZAP data or third-party perspective with ANA-LIS data at age 85. Probabilistic sensitivity analyses favored LPI until starting age 85.

Conclusions: Prophylactic LPI for PACS is cost-effective across a spectrum of ages and should be considered from a public health perspective.