Postoperative Blood Urea Nitrogen-to-Albumin Ratio Predicts 90-Day Mortality Following Burn Surgery

The blood urea nitrogen-to-albumin ratio (BAR) is an emerging prognostic marker that combines information about renal perfusion, protein metabolism, and nutritional and inflammatory status. BAR has potential as a simple and objective indicator of mortality risk in burn populations. This study evaluated whether the postoperative BAR is a useful prognostic marker of 90-d mortality following burn surgery.

This retrospective study included adult burn intensive care unit patients who underwent surgery between 2013 and 2022. Postoperative BAR was calculated within 24 h of burn surgery. The primary outcome was postoperative 90-d mortality. Secondary outcomes were postoperative sepsis, pneumonia, and acute kidney injury. Multivariate Cox proportional hazards regression, receiver operating characteristic curve, Kaplan-Meier, propensity score matching, conditional logistic regression, and stratified Cox regression analyses were conducted.

Among 982 patients, the overall 90-d mortality rate was 26.5%. Multivariate Cox proportional hazards regression analysis identified postoperative BAR as an independent predictor of 90-d mortality. The area under the receiver operating characteristic curve for BAR predicting 90-d mortality was 0.818, with an optimal cutoff of 6.5. Kaplan-Meier analysis showed significantly lower survival in patients with BAR ≥ 6.5 (log-rank P < 0.001). After 1:1 propensity score matching, BAR ≥ 6.5 was significantly associated with increased 90-d mortality (hazard ratio, 2.05; 95% confidence interval [CI], 1.25-3.38; P < 0.001) and also with higher odds of sepsis (odds ratio [OR], 2.58; 95% CI, 1.19-5.61; P = 0.016), pneumonia (OR, 2.10; 95% CI, 1.20-3.67; P = 0.009), and acute kidney injury (OR, 5.88; 95% CI, 2.23-15.5; P < 0.001).

Postoperative BAR ≥ 6.5 is independently associated with 90-d mortality and major complications following burn surgery. It can serve as a useful adjunct for early postoperative risk stratification.