Medical care costs associated with traumatic brain injury over the full spectrum of disease: a controlled population-based study.

Data on traumatic brain injury (TBI) economic outcomes are limited. We used Rochester Epidemiology Project (REP) resources to estimate long-term medical costs for clinically-confirmed incident TBI across the full range of severity after controlling for pre-existing conditions and co-occurring injuries. All Olmsted County, Minnesota, residents with diagnoses indicative of potential TBI from 1985-2000 (n=46,114) were identified, and a random sample (n=7175) was selected for medical record review to confirm case status, and to characterize as definite (moderate/severe), probable (mild), or possible (symptomatic) TBI. For each case, we identified one age- and sex-matched non-TBI control registered in REP in the same year (±1 year) as case's TBI. Cases with co-occurring non-head injuries were assessed for non-head-injury severity and assigned similar non-head-injury-severity controls. The 1145 case/control pairs for 1988-2000 were followed until earliest death/emigration of either member for medical costs 12 months before and up to 6 years after baseline (i.e., injury date for cases and comparable dates for controls). Differences between case and control costs were stratified by TBI severity, as defined by evidence of brain injury; comparisons used Wilcoxon signed-rank plus multivariate modeling (adjusted for pre-baseline characteristics). From baseline until 6 years, each TBI category exhibited significant incremental costs. For definite and probable TBI, most incremental costs occurred within the first 6 months; significant long-term incremental medical costs were not apparent among 1-year survivors. By contrast, cost differences between possible TBI cases and controls were not as great within the first 6 months, but were substantial among 1-year survivors. Although mean incremental costs were highest for definite cases, probable and possible cases accounted for>90% of all TBI events and 66% of total incremental costs. Preventing probable and possible events might facilitate substantial reductions in TBI-associated medical care costs.