Variations in cataract extraction rates in Medicare prepaid and fee-for-service settings.

ObjectiveTo compare rates of cataract extraction in 2 prepaid health settings and in traditional fee-for-service (FFS) settings.DesignA cross-sectional analysis using 1993 health maintenance organization (HMO) Medicare claims and encounter files, the Health Care Financing Administration (HCFA) 5% Medicare Part B provider/supplier file, and the HCFA October 1992 100% Medicare population file.SettingSouthern California Medicare FFS settings and the staff-model and independent practice association (IPA) plans of a large California HMO.Patients1993 Medicare beneficiaries aged 65 years and older. The study included 43387 staff-model HMO enrollees, 19050 IPA enrollees, and 47 150 FFS beneficiaries (a 5% sample of all Southern California FFS beneficiaries).Main outcome measureAge and risk-factor adjusted rates of cataract extraction per 1000 beneficiary-years.ResultsAfter controlling for age, sex, and diabetes mellitus status, FFS beneficiaries were twice as likely to undergo cataract extraction as were prepaid beneficiaries (P<.01). Female FFS beneficiaries were nearly twice as likely to undergo the procedure as were male FFS beneficiaries (P<.001); there were no extraction rate differences by sex in the prepaid settings.ConclusionBecause of the potential implications for vision care in the elderly, the significantly different rates of cataract extraction in FFS and prepaid settings warrant further clinical investigation to determine whether there is overuse in FFS vs underuse in prepaid settings. Such investigations must assess the appropriateness of cataract surgery by evaluating its use relative to clinical need