The direct and indirect effects of cost-sharing on the use of preventive services

Abstract

Objective: To test empirically a model for estimating the direct and indirect effects of different forms of cost-sharing on the utilization of recommended clinical preventive services. DATA SOURCES/SETTINGS: Stratified random sample of 10,872 employees, 18-64 years, who had belonged to their plan for at least one year, from seven large companies that were members of the Pacific Business Group on Health (PBGH) in 1994.

Data collection: The 1994 PBGH Health Plan Value Check Survey. 1994 PBGH data on requirements for employee out-of-pocket patient cost-sharing for 52 different health plans.

Design: Five equations were derived to estimate the direct and indirect effects of two forms of cost-sharing (copayments and coinsurance/deductibles) in two forms of managed care (HMOs and PPO/indemnity plans) on four clinical preventive services: mammography screening, cervical cancer screening, blood pressure screening, and preventive counseling. Probit models were used to estimate elasticities for the indirect and direct effects.

Principal findings: Both forms of cost-sharing in both plan types had negative and significant indirect effects on preventive counseling (from -1 percent to -7 percent). The direct effect of cost-sharing was negative for preventive counseling (-5 percent to -9 percent) and Pap smears (from -3 percent to -9 percent) in both HMOs and PPOs, and for mammography only in PPOs (-3 percent to -9 percent). The results of the effects on blood pressure screening are inconclusive.

Conclusions: Both the direct and indirect effects of cost-sharing negatively affected the receipt of preventive counseling in HMOs and PPOs. As predicted, the direct negative effect of cost-sharing was greater than the indirect effect for Pap smears and mammography. Eliminating cost-sharing for these services may be important to increasing their utilization to recommended levels.