Use of Global Visual Acuity Data in a time trade-off approach to calculate the cost utility of cataract surgery

Abstract

Objective: To determine the cost utility of cataract surgery worldwide using visual acuity (VA) outcomes and utility values determined by the time trade-off (TTO) method.

Data sources: Some cost data were taken from a previous search conducted for 1995 to 2006 and we searched MEDLINE and Scopus and Google for more recent data (2006 and 2007).

Study selection: Articles were identified from the literature using "cataract surgery" in combination with the terms outcome or visual acuity. Additional searches were conducted using individual countries as a term in combination with VA, outcome, or cost. Regression curves were constructed from utility values derived from a TTO study and VA data. Gains in quality-adjusted life-years (QALYs) were calculated based on life expectancy tables from the World Health Organization and discounts of 3% for both cost and benefit. Sensitivity analyses explored the effect of changes in discounting, life expectancy, preoperative VA, and cost.

Data extraction: If the data were usable, they were kept; otherwise they were discarded.

Data synthesis: Preoperative VA (logMAR) correlated with increasing gross national income per capita (Pearson correlation coefficient, -0.784; P < .001) and showed that in developing countries preoperative vision is much poorer compared with developed countries. Cost utility data ranged from $3.5 to $834/QALY in developing countries to $159 to $1356/QALY in developed countries. Sensitivity analysis showed that changing life expectancy, VA, and discount rate resulted in moderate changes.

Conclusions: The TTO approach demonstrates that cataract surgery is extremely cost-effective.