Regional variation in hospital mortality and 30-day mortality for injured Medicare patients.

ABSTRACT

BACKGROUND: We sought to evaluate how survival of older patients with injuries differs by geographic region within the United States. METHODS: We analyzed Medicare fee-for-service records for patients aged 65 years and older with principal injury diagnoses (ICD-9 800-959, excluding 905, 930-939, 958). Cases were classified by Maximum Abbreviated Injury Score (AISmax) and Charlson Comorbidity score (0, 1, 2, >or=3). Hospital mortality and 30-day mortality were modeled as functions of age, sex, AISmax, comorbidity, and geographic region (northeast, midwest, south, west). RESULTS: Hospital and 30-day mortality were both higher with male sex and increased age, AISmax, or Charlson score. Adjusted hospital mortality was highest in the northeast and south, but 30-day adjusted mortality was lowest in the same two regions. CONCLUSIONS: Regional differences in risk-adjusted hospital survival for older patients with injuries are different from regional differences in 30-day survival. Hospital mortality as an outcome for older injured patients should be interpreted cautiously.