Abstract
Purpose: :
Acute primary angle closure (APAC) is one of a few true emergencies in ophthalmology, and requires immediate intraocular pressure (IOP) control to prevent long-term morbidity and permanent vision loss. Recently, evidence has begun to emerge that clear lens extraction (cataract surgery) may be an effective alternative to peripheral laser iridotomy as a means of controlling intraocular pressure1. We determined the cost-effectiveness of laser peripheral iridotomy (LPI) versus clear lens extraction (CLE) as first-line intervention for APAC.
Methods: :
We constructed a Markov model to evaluate cost-effectiveness. We used estimated effectiveness data from a clinical trial1 to determine the number of medications needed to control pressure following each procedure, and the probability of successfully controlling IOP. Patients receiving LPI were assumed to require subsequent definitive trabeculectomy. Both CLE and trabeculectomy were assumed to lead to endophthalmitis with subsequent vision loss at low probabilities estimated from the literature. Standard utilities for monocular vision loss were obtained from literature and used to estimate the cost per change in quality-adjusted life year (QALY) saved. Long-term medication costs was estimated based on the least expensive wholesale prices from the Drug Prices Red Book (2010). The analytic time horizon was five years, a societal perspective was used, and results were computed with a discount rate of 3%.
Results: :
For a time horizon of five years, CLE appears to be cost-saving. Provided the probability of a trabeculectomy following LPI exceeds approximately 6.4%, clear lens extraction yields fewer severe adverse outcomes (i.e. endophthalmitis). The incremental cost-effectiveness ratio of LPI as opposed to CLE suggests an incremental cost-effectiveness ratio of over $5 million per additional QALY saved.
Conclusions: :
CLE was found to be more cost-effective than LPI as first-line treatment for APAC. Our results support the possibility of lens extraction as first-line treatment for primary angle closure, and mark the topic as one deserving of further evaluation.1. Lam DS et al. Randomized trial of early phacoemulsification versus peripheral iridotomy to prevent intraocular pressure rise after acute primary angle closure. Ophthalmology 2008; 115(7): 1134-1140.
Keywords: clinical (human) or epidemiologic studies: health care delivery/economics/manpower