The Controlling Nutritional Status Score and Postoperative Complication Risk in Gastrointestinal and Hepatopancreatobiliary Surgical Oncology: A Systematic Review and Meta-Analysis

Abstract
The controlling nutritional status (CONUT) score is associated with prognosis in gastrointestinal (GI) cancer patients, but the clinical significance of the CONUT score for postoperative short-term outcome remains controversial. The aim of this study was to investigate the impact of the CONUT score on postoperative outcomes in patients with GI and hepatopancreatobiliary (HPB) cancers. We conducted a systematic literature search of Embase, Medline Ovid, Web of Science, Cochrane CENTRAL, and Google Scholar. Meta-analyses were performed to estimate the pooled risk ratio (RR) for postoperative complications in patients with lower ­CONUT score versus higher CONUT score. Furthermore, we explored the most appropriate cutoff value of the CONUT score to predict postoperative complications. Ten retrospective studies (5,138 patients) were included in this meta-analysis. Patients with higher CONUT score had an increased risk of mortality (RR 5.38, 95% CI 2.19–13.2, p < 0.001, I2 = 0%), postoperative major complications (RR 1.56, 95% CI 1.05–2.33, p= 0.03, I2 = 79%), and overall complications (RR 1.38, 95% CI 1.16–1.63, p < 0.001, I2 = 6%). We found that the cutoff of CONUT ≤4 vs. CONUT ≥5 had the highest pooled RR compared with other cutoff values (RR 4.79, 95% CI 0.97–23.5, p= 0.05, I2 = 91%). In conclusion, the present study suggests that the preoperative CONUT score was associated with an increased risk of mortality and complications in GI and HPB surgical oncology. Patients with higher CONUT score as compared with those having a lower score had approximately a fivefold mortality risk and an increased risk up to 55% on major and overall complications after GI and HPB surgery. Our analysis indicates that the appropriate cutoff value of the CONUT score to predict postoperative major complications would be between 4 and 5. The preoperative evaluation of the CONUT score would be helpful for predicting the risk of postoperative outcomes.