Role of Serum Creatinine-to-Cystatin C Ratio in Predicting Postoperative Infectious Complications After Major Urologic Cancer Surgery

Background Sarcopenia has been linked to an increased risk of postoperative complications and poor prognosis in patients undergoing major surgery for urological cancer. The sarcopenia index has emerged as a potential marker of muscle mass. This study investigated the relationship between the sarcopenia index and the occurrence of postoperative infections in patients undergoing major urological surgery. Methods A total of 416 patients who underwent radical cystectomy, prostatectomy, nephrectomy, partial nephrectomy, or nephroureterectomy between April 2023 and May 2024 were retrospectively analyzed. The sarcopenia index was determined using the following formula: [(serum creatinine/serum cystatin C) ×100]. An optimal threshold for the sarcopenia index was established by using receiver operating characteristic curve analysis. The primary endpoint was the incidence of postoperative infectious complications, including pneumonia, urinary tract infections, and surgical site infections. Secondary endpoints were the incidence of urinary tract infection and total postoperative complications. Results Of the 416 included patients, 172 (41%) had a sarcopenia index below the determined threshold. Postoperative infectious complications were more in patients with lower sarcopenia index values than in those with higher values (11% vs. 3%, P  = 0.0014). However, no significant association was found between the sarcopenia index and secondary endpoints. Multivariate analysis identified a reduced sarcopenia index and radical cystectomy as independent predictors of postoperative infections. Conclusion Patients undergoing major urological cancer surgery with a lower sarcopenia index are at an elevated risk of developing postoperative infectious complications. The sarcopenia index may help clinicians predict postoperative infectious events and improve perioperative management.