The risk of amyotrophic lateral sclerosis was more than doubled among patients with traumatic brain injury compared with matched controls, according to a recent study.

The researchers conducted a retrospective cohort study to examine the association between traumatic brain injury (TBI) and subsequent risk of amyotrophic lateral sclerosis. Using UK-wide electronic health records from the Clinical Practice Research Datalink, Hospital Episode Statistics, and Office for National Statistics mortality data, the investigators analyzed patients 18 years and older with a history of TBI (n = 85,690) matched to comparators without TBI (n = 257,070) based on age, sex, and area deprivation, for a total cohort of 342,760 participants. Median follow-up was 5.72 years, providing 2.13 million person-years of observation.

During follow-up, 150 new amyotrophic lateral sclerosis (ALS) cases were identified, corresponding to an overall incidence rate of 7.05 per 100,000 person-years. Among patients with TBI, 69 developed ALS (0.08%) compared with 81 of those without TBI (0.03%). Published in JAMA Network Open, this represented incidence rates of 13.12 per 100,000 person-years in the TBI group and 5.05 per 100,000 person-years in the comparator group, indicating more than a twofold increased risk of ALS after TBI.

“This was confirmed in a time-dependent analysis, which revealed risk of ALS was highest in the 2 years immediately following TBI (hazard ratio, 6.18; 95% confidence interval, 3.47-11.00; P < .001), attenuating thereafter to no different from that of matched population comparators,” noted the lead author Xingxing Zhu, PhD, of the School of Health and Wellbeing, University of Glasgow, Glasgow, United Kingdom, and colleagues. The mean age at ALS diagnosis was similar between patients with TBI and comparators (69.7 vs 68.2 years), as was the mean age at death with ALS (72.2 vs 72.0 years).

The researchers reported no conflicts of interest.

Source: JAMA Network Open