Background: Bariatric surgery has become the most common and effective therapeutic option for obesity. However, it is associated with morbidity and complications. Identification of predictors for surgical complications is an unmet need.

Objectives: To determine a simple non-invasive parameter that predicts early postoperative complications following bariatric surgery.

Methods: In this retrospective study of all patients who underwent elective bariatric surgery at Nazareth Hospital EMMS during a 4-year period (2015–2018). We collected clinical and laboratory parameters and determined predictors of complications.

Results: A total of 345 patients underwent bariatric surgery during the study period. Of the patients, 51 experienced early post-bariatric surgery complications as compared to 294 patients who had no complications. Univariate analysis revealed that neutrophil-to-lymphocyte ratio (NLR) (odds ratio [OR] 1.912, P < 0.0001) and platelet to lymphocyte ratio (OR 1.015, P < 0.0001) were associated with post-bariatric surgery complications. In a multivariate logistic regression analysis, only NLR remained a significant predictor (OR 1.751, 95% confidence interval 1.264–2.425, P = 0.0008) with a receiver operating characteristic curve for NLR of 0.8404.

Conclusions: We found that the NLR predicts post bariatric surgery early complications. Further prospective studies are needed to validate our findings.