Platelet to white blood cell ratio predicts 30-day postoperative infectious complications in patients undergoing radical nephrectomy for renal malignancy.

INTRODUCTION: We sought to examine the relationship between preoperative platelet to white blood cell ratio (PLT/WBC), a hematological marker of the systemic inflammatory response, and postoperative infectious complications following radical nephrectomy for localized renal cell carcinoma.

METHODS: We performed a retrospective cohort study of patients treated with radical nephrectomy for localized kidney cancer between January 1, 2005 and December 31, 2014 (n=6235) using the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database. Univariate and multivariate analyses were used to assess the association between PLT/WBC ratio and 30-day infectious complications, including surgical site infection, urinary tract infection (UTI), pneumonia, and sepsis. Secondarily, we examined major complications and bleeding requiring transfusion.

RESULTS: A lower PLT/WBC ratio was associated with an increased risk of sepsis, pneumonia, and UTI rates (p<0.05 for all). Furthermore, there was a significant trend of decreasing rates of sepsis and pneumonia with increasing PLT/WBC ratio across quintiles (p<0.05 for all). On multivariate analysis, patients with the lowest PLT/WBC ratios (Quintile 1) had a two-fold risk of having a postoperative infectious complication compared to patients in the highest quintile (odds ratio [OR] 2.01; 95% confidence interval [CI] 1.42-2.86; p<0.0001). Patients in Quintile 5 had a higher risk of requiring blood transfusion than those in Quintiles 2-4 (p<0.05 for all).

CONCLUSIONS: The PLT/WBC ratio represents a widely available and novel index to predict risk of infectious and bleeding complications in patients undergoing radical nephrectomy. External validation is required and the biological underpinning of this phenomenon requires further study.