A Multivariable Model of the Association Between Postoperative Complications and 30-Day In-Hospital Mortality in the African Surgical Outcome Study Cohort

BACKGROUND: The perioperative mortality rate in Africa is twice the global average. Postoperative complications independently associated with postoperative mortality have not been explored in this region and can provide insight into failure to rescue. The aim of this study was to determine which severe postoperative complications are independently associated with postoperative mortality in Africa and calculate the attributable fraction (AtF) for 30-day mortality for each complication. METHODS: Data from an African prospective observational study of perioperative adult patients conducted in 2016 were analyzed. We used a logistic mixed-effects model to assess the strength of association, expressed as an odds ratio (OR), between severe postoperative complications and 30-day postoperative mortality, adjusting for known patient and surgical factors. This model was used to calculate the AtF of death for each complication, representing the proportion of mortality due to that complication. RESULTS: We included 10,748 patients, of whom 222 (2.07%) died in hospital within the 30-day postoperative period. The severe postoperative complications with the highest adjusted ORs for mortality were pulmonary embolism (OR, 484; 95% confidence interval [CI], 85.2–2744; P < .001), pulmonary edema (OR, 53.5; 95% CI, 6.59–434; P < .001) and bloodstream infections (OR, 34.3; 95% CI, 16.3–72.3; P < .001). The highest AtF for 30-day postoperative mortality was severe bloodstream infections (average AtF 13.7%; 95% CI, 10–18.1). CONCLUSIONS: The AtF is a measure that can identify the complications with the greatest contribution to postoperative mortality and can guide prioritization. In this African cohort, pulmonary embolism, pulmonary edema, and bloodstream infections were most strongly associated with death, while severe bloodstream infections accounted for the largest proportion of 30-day mortality. Managing bloodstream infections is an important complication to address to improve postoperative outcomes in Africa.