Impacts of Medicare HMO penetration on utilization and health outcomes of stroke care

Advancement in technologies is a driving force behind the rapid growth in health care expenditures in the past decades. Managed care is a potential tool to slow the growth, but its efficiency is still poorly understood. The objective of the study is to examine the effects of Medicare HMO penetration on utilization of carotid endarterectomy (CEA), stroke outcomes, and post-CEA care. An additional innovation is to explicitly examine differential effects of IPA and non-IPA HMO penetration.; Individual, hospital, and county-level panel data sets were constructed from the nationally representative Nationwide Inpatient Sample (1993–98) and Vital Statistics Cause of Death file, merged with Medicare HMO penetration data. Multivariate models with hospital or county fixed effects were used to control for HMO selection.; The analyses show that Medicare HMO penetration was not significantly associated with the utilization rate of CEA. The effects on stroke outcomes are mixed. Increased Medicare HMO penetration was not associated with the hospitalized stroke rate but was significantly positively associated with the population-level county stroke mortality rate (p < .05). With respect to post-CEA care, increased Medicare HMO penetration was significantly associated with earlier discharge and lower probability of home health care utilization.; The impact of IPA and non-IPA HMO penetration differed marginally only for the stroke mortality rate (p < .1), and CEA patients in areas with higher non-IPA HMO penetration were more aggressively discharged and had lower utilization rate of home health care than those in areas with higher IPA HMO penetration. However, no evidence supports the associations between Medicare HMO penetration and the probability of use of SNFs and in-hospital CEA mortality rate.; As policymakers contemplate expanding the HMO program to the elderly, the anticipated cost-savings from the program is uncertain. The findings indicate that between 1993 and 1998 increased Medicare HMO penetration had little influence on the utilization rate of CEA but was associated with worsened stroke outcomes. More evidence on the impact of managed care on a variety of technologies and outcomes as well as other stroke interventions is needed before firm conclusions can be drawn.