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 (β = 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.