Undernourished and Under the Knife: How Preoperative Albumin Exposes Surgical Risk

Serum albumin reflects nutritional status and allostatic load, making it useful for surgical risk assessment in undernourished populations. Chronic socioeconomic and environmental stress can cause weathering, an accelerated decline in physiological reserve that may increase surgical vulnerability in disadvantaged patients. We aimed to define a locally optimized preoperative serum albumin cutoff for predicting 30-d postoperative mortality in our population.

We performed a secondary analysis of ACS-NSQIP data (2019-2023) from a tertiary-care center in Karachi, Pakistan. Adults undergoing major elective procedures with available preoperative albumin were included. Multivariable Cox regression assessed the association between albumin and 30-d mortality after adjustment for sex, age, body mass index, diabetes, smoking, immunosuppression, and hypertension. Kaplan-Meier curves were generated using the identified albumin cutoff and compared with the log-rank test.

Among 1019 patients (50.1% female), the optimal preoperative albumin cutoff for 30-d mortality was 3.55 g/dL (area under the curve: 0.82; sensitivity 70%, specificity 79%). Using this threshold, 248 patients (24.3%) had albumin <3.55 g/dL. In the fully adjusted model, low albumin was independently associated with 30-d mortality (hazard ratio: 2.83, 95% confidence interval: 1.50-5.33), whereas other covariates were not statistically significant. Kaplan-Meier analysis showed significantly lower survival in the albumin <3.55 g/dL group (log-rank P < 0.01). Albumin performed poorly for predicting any postoperative complication (area under the curve: 0.65).

Preoperative hypoalbuminemia was independently associated with an increased hazard of 30-d postoperative mortality. A locally derived cutoff of 3.55 g/dL may help identify nutritionally vulnerable patients and support elective delay and targeted nutritional optimization.