Prior Concussions and Risk of Disability for Patients After a Motor Vehicle Crash

TL;DR

Having a prior concussion increases the risk of long-term disability after a motor vehicle crash, according to a large study of Canadian patients.

Contribution

The study identifies a 15% increased risk of long-term disability following a motor vehicle crash for individuals with a prior concussion.

Findings

Patients with a prior concussion had a 15% higher adjusted risk of long-term disability after a motor vehicle crash.

The increased risk was consistent across crash severity and patient groups, and was confirmed using artificial intelligence models.

The risk was independent of other factors and not linked to higher short-term healthcare costs or mortality.

Abstract

Is a prior concussion associated with an increased risk of long-term disability following a motor vehicle crash?

In this cohort study of 907 984 adult patients, a prior concussion was associated with a 15% increased risk of long-term disability.

This finding suggests the importance of counseling patients about the risks of motor vehicle crashes and previous concussions, as well as the importance of follow-up care to reduce the risk of subsequent disability.

This cohort study of Canadian adults surviving a motor vehicle crash examines the association of prior concussions with risk of long-term disability.

Recovery after a motor vehicle crash can be slow, frustrating, and incomplete with lingering neurocognitive complications.

To examine whether a prior concussion is associated with increased risk of long-term disability after a motor vehicle crash.

This cohort study included adults surviving a motor vehicle crash treated in Ontario, Canada, from April 2003 to March 2023 with analyses to November 2025.

Prior concussion.

Long-term disability defined by official social service records, comparing those with a prior concussion and those with no history of a prior concussion.

A total of 907 984 patients injured in a motor vehicle crash were included (mean [SD] age, 37 [14] years; 472 435 male [52.0%]); 19 851 patients had a prior concussion and 888 133 had no prior concussion. A total of 54 678 patients were subsequently diagnosed with long-term disability over 9 543 505 patient-years of follow-up (mean [SD], 10.5 [5.8] years), equal to an absolute risk of 1 in 17 per decade (5.7 per 1000 patient-years). Patients with a prior concussion had a 15% higher adjusted risk of long-term disability (95% CI, 9%-21%; P < .001) compared with those with no prior concussion. The increased risk of long-term disability was independent of other measured risk factors, applied to diverse patient groups, and included those involved as passengers or pedestrians. The increased risk extended across a spectrum of crash severity, was accentuated for single-vehicle events, replicated in analyses with artificial intelligence models adjusting for confounding, and remained distinct from the risks of death, readmission, or short-term health care costs.

This population-based cohort study suggests a significant increased risk of long-term disability after a motor vehicle crash, particular among patients with a prior concussion. More efforts at concussion prevention and traffic safety counseling may be justified for patients.

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