Louis F. Rossiter

Examining the real effect of prior utilization on subsequent utilization

Measures of health status and prior service use have been considered promising predictors of future health expenditures, particularly when used for risk-adjustment models in capitation payment systems. While the use of health status as a future predictor has its difficulty in terms of measurement accuracy and implementation costs, using prior utilization as the base for the calculation of future health expenditures also has its concerns. Based on a three-stage cross-lagged model in a longitudinal study design, this study showed that prior utilization has both a direct and an indirect effect on subsequent utilization. However, the real net effect of prior utilization on subsequent utilization can be overestimated by 25%, if the effect of health status is not taken into account.

Effect of Different Types of Medicaid Managed Care on Childhood Immunization Rates

Medicaid managed care can improve access to prevention services, such as immunization, for low-income children. The authors studied immunization rates for 7,356 children on Medicaid in three managed care programs: primary care case management (PCCM; n = 4,605), a voluntary HMO program (n = 851), and a mandatory HMO program (n = 1,900). Immunization rates (3:3:1 series) in PCCM (78%) exceeded rates in the voluntary HMO program (71%), which in turn exceeded those in the mandatory HMO program (67%). Adjusting for race, urban residence, and gender, compared to children in PCCM, children in the voluntary HMO program were less likely to complete the 3:3:1 series (OR = 0.75, CI = 0.63, 0.90), and children in the mandatory HMO program were even less likely to complete the series (OR = 0.59, CI = 0.51, 0.68). Results differed by individual HMOs. Monitoring of outcomes for all types of managed care by Medicaid agencies is imperative to assure better disease prevention for low-income children.