摘要：Objectives. We evaluated the generalizability of Medicare fee-for-service data for patients hospitalized with injuries. Methods . We used 1998–2000 Medicare hospitalization data and National Hospital Discharge Survey (NHDS) data to analyze patients aged 65 years and older with principal injury diagnoses. Results . Demographics and injury patterns were similar in Medicare data and NHDS Medicare data. Injured patients without Medicare or health maintenance organization coverage were younger, less likely to have hip fractures, and more likely to have head or chest injuries. Mortality and discharge to long-term care were not significantly affected by insurance coverage, after we controlled for injury type and severity, age, gender, and comorbidity. Medicare patients had slightly longer hospital lengths of stay. Conclusions. Hospital outcomes are generally similar among older patients with a given anatomic injury, regardless of insurance coverage. Among patients admitted to American hospitals after injury, older persons have become the dominant group, a trend that is likely to continue as the population ages. 1 For these patients, Medicare fee-for-service data are a promising resource for injury research, because they include a large proportion of the population aged 65 years and older; are available in the same format for all states; and allow linkage of encounters before, during, and after an index hospitalization. Samples of Medicare hospitalization data have been used for general descriptions of injury epidemiology and cost 2 and specifically to study the incidence of common fractures. 3, 4 Several groups have studied geographic variation in the incidence of fractures of the femoral neck (hip), with conflicting explanations of this variation. 5– 7 Such studies rely on the assumption that the number of Medicare claims for hospital treatment of a fracture represents the incidence of such fractures in the general population. Research using Medicare data to determine the outcomes of hospital care for injured patients has also begun to appear. Gubler et al. 8, 9 linked Medicare hospital data to subsequent encounters and mortality to measure recurrence and long-term survival after hospitalization for injury in the state of Washing-ton. Rzepka et al. 10 used Medicare data to compare outcomes of injured patients in various hospitals nationwide, controlling for age, gender, and race, but paradoxically reported an increased mortality in specialized trauma centers. There are well-described limitations in the analysis of hospital discharge data in general 11 and Medicare data in particular. 12 Although most Americans aged 65 years and older are enrolled in Medicare, differences in coverage by age and race have been reported in the past. 12 Furthermore, a significant number of Medicare enrollees also participate in managed care plans and therefore may not submit Medicare claims; this proportion varies by region and tends to be greatest in urban areas. 13 Because of the known differences in the incidence of different kinds of injuries by age, race, and residence, we wanted to determine whether it was reasonable to generalize results from fee-for-service Medicare data to the older population as a whole. Furthermore, any differences in outcomes for the population not insured by Medicare might suggest areas in which trauma care systems require improvement or additional resources.
