Worldwide Variation in Case Mix, Quality of Care and Mortality of Patients Receiving Emergency Neurosurgery for Traumatic Brain Injury in the Global Neurotrauma Outcomes Study (GNOS) – A Prospective, Observational Cohort Study Involving 1,635 Patients in 159 Hospitals in 57 Countries

Background: Traumatic brain injury (TBI) is increasingly recognised as being responsible for a substantial proportion of the global burden of disease. Neurosurgical intervention for TBI is an extremely important aspect of its care but epidemiological data on this patient population are lacking. We aimed to characterise differences in case mix, quality of care and in-hospital mortality of TBI across human development settings. Methods: This was a prospective, observational cohort study of consecutive TBI patients undergoing emergency neurosurgery conducted in a convenience sample of 159 hospitals in 57 countries. The primary outcome measure was survival to discharge or 14-days post-operatively (whichever came first). Countries were stratified according to their Human Development Index (HDI) into very high (VH-HDI), high (H-HDI), medium (M-HDI) and low (L-HDI). Mixed effects logistic regression was used to examine the effect of HDI on mortality while accounting for and quantifying between-hospital and country variation. The study was registered on ClinicalTrials.gov, NCT04212754. Findings: Of the 1,635 patients enrolled between 1 November 2018 and 31 January 2020, 328 (20%) were from VH-HDI, 539 (33%) from H-HDI, 614 (38%) from M-HDI and 154 (9%) from L-HDI countries. There was significant variation in age, mechanism of injury, severity of TBI and procedure performed as well as preoperative and postoperative care across countries and HDI tiers. Overall mortality was 18%. After adjustment for case mix, the odds of in-hospital mortality were greater in the M-HDI (OR 2.84 95% CI 1.55-5.2) and H-HDI (OR 2.26 95% CI 1.23-4.15) tiers relative to the VH-HDI tier. There was significant between-hospital variation in mortality (MOR 2.00 95% CI 1.17-2.49). Interpretation: Patients receiving emergency neurosurgery for TBI differed considerably in their admission characteristics, management received and outcomes across human development settings. Level of human development was associated with mortality. Funding: National Institute for Health Research Global Health Research Group. Declaration of Interest: All authors declare no competing interests. Ethical Approval: UK National Health Service Research Ethics Service considered this study exempt from formal research registration (South East Scotland Research Ethics Service)