Previous data show conflicting results regarding the association between MS and prior brain trauma. This study aimed to investigate the risk for MS following a traumatic brain injury (TBI) using a population-based dataset. This study used data from the National Health Insurance Research Database. In total, 72,765 patients with TBI were included as the study cohort, and 218,295 randomly selected subjects were matched with the study cohort by sex and age as controls. We traced each patient individually for a six-year period from their index health care utilization to identify those who received a subsequent diagnosis of MS.
We used the Kaplan-Meier method and the log-rank test to compare the difference in six-year MS-free survival rates between the two groups. Stratified Cox proportional hazard regressions were computed to compare the risk of developing MS for these two cohorts.
The incidence rate of MS was 10.51 (95% CI: 7.60-14.16) per 100,000 person-years in patients with TBI and 6.63 (95% CI: 5.30-8.20) per 100,000 person-years in patients without TBI. After censoring cases who died from non-MS causes, stratifying for hospitalization of cases as a proxy for severity, and adjusting for monthly income and geographic region of the community in which the patient resided, the Hazard Ratio (HR) of MS for patients with hospital-treated TBI injuries was 1.97 (95% CI=1.31-2.93, p<0.01) that of patients without TBI during the six-year follow-up period after index healthcare use.
Our study concludes that patients with TBI are at higher risk for subsequent MS over a six-year follow-up period.
"This study supports head injury being a risk factor for the development of MS. It will be controversial considering how many legal cases there have been on this topic. Time for a more definitive study to be done."