Low Preoperative Serum Creatinine is Common and Associated With Poor Outcomes After Nonemergent Inpatient Surgery

OBJECTIVE: To assess the association between low preoperative serum creatinine and postoperative outcomes. BACKGROUND: The association between low creatinine and poor surgical outcomes is not well understood. METHODS: We identified patients with creatinine in the 7 days preceding nonemergent inpatient surgery in the American College of Surgeons National Surgical Quality Improvement Program database from 2005 to 2020. Multivariable logistic regression was used to examine the association between creatinine and 30-day mortality and major complications. RESULTS: Of 1,809,576 patients, 27.8% of males and 23.5% of females had low preoperative serum creatinine, 14.6% experienced complications, and 1.2% died. For males, compared with the reference creatinine of 0.85 to 1.04, those with serum creatinine ≤0.44 had 55% increased odds of mortality [ adjusted odds ratio (aOR), 1.55; 95% CI, 1.29-1.86] and 82% increased odds of major complications (aOR, 1.82; 95% CI, 1.69-1.97). Similarly, for females, compared with the reference range of 0.65 to 0.84, those with serum creatinine ≤0.44 had 49% increased odds of mortality (aOR, 1.49; 95% CI, 1.32-1.67) and 76% increased odds of major complications (aOR, 1.76; 95% CI, 1.70-1.83). These associations persisted for the total cohort, among those with mildly low albumin, and for those with creatinine values measured 8 to 30 days preoperatively. CONCLUSIONS: A low preoperative creatinine is common and associated with poor outcomes after nonemergent inpatient surgery. A low creatinine may help identify high-risk patients who may benefit from further evaluation and optimization.