To investigate the prognostic value of the Subgroups for Targeted Treatment (STarT) Screening Tool adapted for concussion (STarT-C) on persistent symptoms and disability at 6–9 months following mild traumatic brain injury (mTBI).

Secondary analysis of two prospective studies: an observational cohort study in New Zealand and usual care control arm of a clinical trial in Canada (ClinicalTrials.gov Registry (NCT04704037)).

Participants in the New Zealand cohort were recruited from concussion clinics (five sites) and those in the Canadian cohort were recruited from emergency departments/urgent care centres (eight sites).

New Zealand participants (n=93, median age 37 years, 60% women) were assessed at median=6 weeks post-injury (T1) and 6 months later (T2). Canadian participants (n=223, median age 38 years, 56% women) were assessed at median=2 weeks (T1) and 6 months later (T2).

Symptoms at T2 were assessed using the validated Rivermead Postconcussion Symptoms Questionnaire (RPQ) and disability using the WHO Disability Assessment Schedule 2.0 12-item Interview.

In linear regression analyses, the STarT-C predicted symptom burden (R²=18–36%) and disability (R²=15–18%) at T2 in both cohorts. While the additional prognostic value over and above baseline variables was substantial (delta R² 8–40%), the additional prognostic value over the RPQ at T1 was variable and generally lower (delta R²=1–9%).

The STarT-C—a brief screening tool—predicted persistent symptoms and disability in adults following mTBI. The incremental prognostic value of the STarT-C over the RPQ may be variable, but regardless, the tool may be useful for identifying those at risk of prolonged recovery who may benefit from early psychological intervention.