Sex-specific associations of preoperative serum uric acid levels with mortality and morbidity in non-cardiac surgeries: a single-center retrospective study.

BACKGROUND

The sex-specific association between serum uric acid (SUA) levels and postoperative outcomes in elective non-cardiac surgery remains unclear. This study aimed to identify sex-specific SUA thresholds and their impact on short- and long-term outcomes.

METHODS

A retrospective analysis of 295 267 patients (2012-2021) undergoing non-cardiac surgery was conducted. Patients were stratified by preoperative SUA levels: for males (< 4 to ≥ 9 mg/dl) and females (< 3 to ≥ 8 mg/dl), with mid-range levels as reference. Mortality (30-day to overall) and complications were assessed using Cox and logistic regression. Cubic splines evaluated nonlinear trends, with subgroup analyses by age and surgical risk.

RESULTS

SUA levels exhibited a nonlinear, sex-specific association with postoperative outcomes. The estimated lower-risk SUA range was 5.08-7.63 mg/dl in males and 3.34-5.35 mg/dl in females. In Cox and spline analyses, a U-shaped association between SUA and mortality was observed in both sexes, with significant risks at both low (< 4 mg/dl) and high (≥ 9 mg/dl) levels in males, and predominantly at low levels (< 3 mg/dl) in females. The types of complications varied subtly between sexes. Within SUA ranges of 4-6 mg/dl (males) and 3-4 mg/dl (females), composite and specific complication risks were lower than at either extreme, showing a protective effect, with reduced risk of acute kidney injury in males and pneumonia in females. Additionally, extreme SUA levels were significantly associated with increased mortality and complications, particularly in low-risk surgical patients.

CONCLUSIONS

Preoperative SUA levels show a nonlinear, sex-specific association with postoperative outcomes, highlighting the need for sex- and risk-based perioperative stratification.