Hospitalization Rates for Ambulatory Care-Sensitive Conditions in California Medicare HMO's

OBJECTIVE: To examine annual hospitalization rates for ambulatory care-sensitive conditions (ACSCs) among Medicare HMO beneficiaries. DESIGN: Cross-sectional descriptive study. Setting and participants: Medicare beneficiaries aged 65 years and older continuously enrolled in 1 of 15 California Medicare HMOs from 1 January through 31 December 2001. MEASUREMENTS: Hospitalization rates overall and for each of 15 ACSCs (bacterial pneumonia, cellulitis, dehydration, gastric and duodenal ulcer, hypoglycemia, hypokalemia, severe ear/nose/throat infections, urinary tract infections, asthma/chronic obstructive pulmonary disease, congestive heart failure, diabetes, hypertension, seizure disorder, influenza, and malnutrition). The rate for the 15 ACSCs combined as well as acute, chronic, and preventable indices were also estimated. RESULTS: Of the 1.2 million Medicare beneficiaries enrolled in California HMOs during 2001, 24% were 80 years or older (range among plans, 15%-34%), 5% were African American (range, 1%-25%), and 6% were Medicaid-eligible (range, 3%-16%). Enrollees experienced a total of 315,503 hospitalizations in 2001 (267 per 1000), 22% of which were for an ACSC. ACSC hospitalization rates varied widely by plan and were higher among older enrollees, males, and those eligible for Medicaid. CONCLUSION: ACSC hospitalization rates are easy to calculate based on administrative data. These rates can be used by individual plans as a method to screen for possible access and quality of care problems.