The Effect of Sentinel Injury on Medicare Expenditures over Time

OBJECTIVES To examine the long-term effect of sentinel injury (unintentional injury involving serious health-related consequences) among older adults on Medicare expenditures. DESIGN Secondary data analysis of the Medicare Current Beneficiary Survey, a nationally representative survey of Medicare Beneficiaries. SETTING Noninstitutionalized community dwellers. PARTICIPANTS Older adults (N=12,318) continuously enrolled in Medicare Fee-for-Service under Old Age Survivors Insurance Benefits surveyed between October 1998 and December 2004. MEASUREMENTS Monthly total Medicare expenditures served as the dependent variable. Injury status (preinjury, injury episode, postinjury) was identified from Medicare claims and specified as a set of dummy variables. Injury episodes began with the first index injury claim identified and ended when no further injury claims were found within 180 days. Population-averaged models using generalized estimating equation techniques were estimated to explore changes in Medicare expenditures over time after adjusting for casemix differences. A case-crossover design was used to compare monthly Medicare expenditures before and after sentinel injury events. RESULTS Fifteen percent of beneficiaries sustained at least one sentinel injury. Medicare expenditures increased sharply during sentinel injury episodes ((beta) over cap = 1.703, P <.001) and remained at least 28% higher than would otherwise be expected for 27 uninterrupted months following injury. Additive Medicare expenditures associated with sentinel injury over 3 years were estimated at $28,885. CONCLUSION Consequences of sentinel injury in older adults extend well beyond the period typically considered to be an acute injury episode. Better understanding of the long-term consequences of injury-related outcomes is needed to achieve public health goals of reducing injury and improving injury-related medical care.