Mortality after hospital admission for trauma in Norway: A retrospective observational national cohort study

Background: National quality data for trauma care in Norway have not previously been reported. We have therefore assessed crude and risk-adjusted 30-day mortality in trauma cases after primary hospital admission on national and regional levels for 36 acute care hospitals and four regional trauma centres. Methods: All patients in the Norwegian Trauma Registry in 2015-2018 were included. Crude and risk-adjusted 30-day mortality was assessed for the total cohort and for severe injuries (Injury Severity Score =16), and individual and combined effects of health region, hospital level, and hospital size were studied. Results: 28,415 trauma cases were included. Crude mortality was 3.1% for the total cohort and 14.5% for severe injuries, with no statistically significant difference between regions. Risk-adjusted survival was lower in acute care hospitals than in trauma centres (0.48 fewer excess survivors per 100 patients, P<0.0001), amongst severely injured patients in the Northern health region (4.80 fewer excess survivors per 100 patients, P = 0.004), and in hospitals with <100 trauma admissions per year (0.65 fewer excess survivors than in hospitals with =100 admissions, P = 0.01). However, the only statistically significant effects in a multivariable logistic case mixadjusted descriptive model were hospital level and health region. Case-mix adjusted odds ratio for survival for severely injured patients directly admitted to a trauma centre vs. an acute care hospital was 2.04 (95% CI 1.04-4.00, P = 0.04), and if admitted in the Northern health region vs. all other health regions was 0.47 (95% CI 0.27-0.84, P = 0.01). The proportion of cases admitted directly to the regional trauma centre in the sparsely populated Northern health region was half of that in the other regions (18.4% vs. 37.6%, P<0.0001).Conclusion: Differences in risk-adjusted survival for severe injuries can to a large extent be attributed to whether patients are directly admitted to a trauma centre. This should have implications for planning of transport capacity in remote areas.

Automated summary

This study assessed the national and regional-level 30-day mortality in trauma cases in Norway after primary hospital admission. It found that risk-adjusted survival for severe injuries is largely determined by whether patients are directly admitted to a trauma center, which has implications for transport capacity planning in remote areas.