Female risk-adjusted survival advantage after injuries caused by falls, traffic or assault: a nationwide 11-year study.

BACKGROUND: A female survival advantage after injury has been observed, and animal models of trauma have suggested either hormonal or genetic mechanisms as component causes. Our aim was to compare age and risk-adjusted sex-related mortality in hospital for the three most common mechanisms of injury in relation to hormonal effects as seen by age.

METHODS: All hospital admissions for injury in Sweden during the period 2001-2011 were retrieved from the National Patient Registry and linked to the Cause of Death Registry. The International Classification of Diseases Injury Severity Score (ICISS) was used to adjust for injury severity, and the Charlson Comorbidity Index to adjust for comorbidity. Age categories (0-14, 15-50, and ≥ 51 years) were used to represent pre-menarche, reproductive and post- menopausal women.

RESULTS: Women had overall a survival benefit (OR 0.51; 95% CI 0.50 to 0.53) after adjustment for injury severity and comorbidity. A similar pattern was seen across the age categories (0-14 years OR 0.56 (95% CI 0.25 to 1.25), 15-50 years OR 0.70 (95% CI 0.57 to 0.87), and ≥ 51 years OR 0.49 (95% CI 0.48 to 0.51)).

CONCLUSION: In this 11-year population-based study we found no support for an oestrogen-related mechanism to explain the survival advantage for females compared to males following hospitalisation for injury.