Modeling the impact of Medicare Advantage payment cuts on ambulatory care sensitive and elective hospitalizations.

OBJECTIVE To assess relationships between changes in Medicare Advantage (MA) payment rates and Medicare beneficiary hospitalizations and to simulate the effects of scheduled payment cuts on ambulatory care sensitive (ACS) and elective hospitalization rates. DATA State Inpatient Database discharge abstracts from Arizona, Florida, and New York merged with administrative Medicare enrollment and MA payment data. STUDY DESIGN Retrospective, fixed effect regression analysis of the relationship between MA payment rates and rates of ACS and elective hospitalizations among Medicare beneficiaries in counties with at least 10,000 Medicare beneficiaries and 3 percent MA penetration from 1999 to 2005. PRINCIPAL FINDINGS MA payment rates were negatively related to rates of ACS admissions. Simulations suggest that payment cuts could be associated with higher rates of ACS admissions. No relationship between MA payments and rates of elective hospitalizations was found. CONCLUSIONS Reductions in MA payment rates may result in a small increase in ACS admissions. Trends in ACS admissions among chronically ill Medicare beneficiaries should be tracked following MA payment cuts.