Background: Extremely few objective estimates of traumatic brain injury incidence include all ages, both sexes, all injury mechanisms, and the full spectrum from very mild to fatal events.
Methods: We used unique Rochester Epidemiology Project medical records-linkage resources, including highly sensitive and specific diagnostic coding, to identify all Olmsted County, MN, residents with diagnoses suggestive of traumatic brain injury regardless of age, setting, insurance, or injury mechanism. Provider-linked medical records for a 16% random sample were reviewed for confirmation as definite, probable, possible (symptomatic), or no traumatic brain injury. We estimated incidence per 100,000 person-years for 1987–2000 and compared these record-review rates with rates obtained using Centers for Disease Control and Prevention (CDC) data-systems approach. For the latter, we identified all Olmsted County residents with any CDC-specified diagnosis codes recorded on hospital/emergency department administrative claims or death certificates during 1987–2000.
Results: Of sampled individuals, 1257 met record-review criteria for incident traumatic brain injury; 56% were ages 16–64 years, 56% were male, and 53% were symptomatic. Mechanism, sex, and diagnostic certainty differed by age. The incidence rate per 100,000 person-years was 558 (95% confidence interval = 528–590) versus 341 (331–350) using the CDC data-system approach. The CDC approach captured only 40% of record-review cases. Seventy-four percent of missing cases presented to the hospital/emergency department; none had CDC-specified codes assigned on hospital/emergency department administrative claims or death certificates; and 66% were symptomatic.
Conclusions: Capture of symptomatic traumatic brain injuries requires a wider range of diagnosis codes, plus sampling strategies to avoid high rates of false-positive events.
From the aDivision of Epidemiology, Department of Health Sciences Research, Mayo Clinic, Rochester, MN; and bDepartment of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN; cDivision of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, MN; dDepartment of Biostatistics, Mayo Clinic, Jacksonville, FL; and eRehabilitation Hospital of Indiana and Department of Physical Medicine and Rehabilitation, Indiana University School of Medicine, Indianapolis, IN.
Submitted 15 October 2010; accepted 7 June 2011.
Supported by TBI Model System grants to Mayo Clinic from the National Institute on Disability and Rehabilitation Research (H133A020507, H133A070013) and a National Research Service Award from the National Institute of Health (Training Grant HD-07447). The study was made possible by the Rochester Epidemiology Project (Grant Number R01 AG034676 from the National Institute on Aging).
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Correspondence: Cynthia L. Leibson, Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905. E-mail: firstname.lastname@example.org.