Comparing Randomized Controlled Trials of Moderate to Severe Traumatic Brain Injury in Lower to Middle Income Countries Versus High Income Countries.

Outcomes from traumatic brain injury (TBI) including death differ significantly between high-, middle-, and low-income countries. Little is known, however, about differences in TBI research across the globe. The objective of this article was to examine randomized controlled trials (RCTs) of moderate-to-severe TBI in high-income countries (HICs) compared with low- and middle-income countries (LMICs), as defined by the World Bank income per capita cutoff of $13,205 US dollars. A systematic review was conducted for articles published in the English language to December 2022 inclusive using MEDLINE, PubMed, Scopus, CINAHL, EMBASE, and PsycINFO in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Inclusion criteria: (1) human participants with a mean age of ≥18 years; (2) ≥50% of the sample had moderate to severe TBI; and (3) the study design was a RCT. Data extracted included author, year, country, sample size, primary focus (medical/surgical management or rehabilitation), injury etiology, time post-injury, and indicator(s) used to define TBI severity. There were 662 RCTs (published 1978-2022) that met inclusion criteria comprising 91,946 participants. There were 48 countries represented: 30 HICs accounting for 451 RCTs (68.1%) and 18 LMICs accounting for 211 RCTs (31.9%). The 62.6% of RCTs from LMICs were conducted in the acute phase post-injury (≤1 month) compared with 42.1% of RCTs from HICs. Of RCTs from LMICs, 92.4% focused on medical/surgical management compared with 52.5% from HICs. Since 2016, more RCTs have been conducted in LMICs than in HICs, indicating the importance of better understanding this pattern of research output.