The Role of Body Mass Index Predicting Outcome of Percutaneous Nephrolithotomy

Abstract

Objective: The objective of this study is to evaluate the impact of body mass index (BMI) on clinical outcomes and safety profiles of percutaneous nephrolithotomy (PCNL). Materials and Methods: We retrospectively reviewed the patients who received PCNL between January 2015 and December 2016. A total of 182 consecutive patients were enrolled. The patients were categorized into three groups according to BMI (normal: BMI ≤24, overweight: 24 < BMI ≤27, obesity: BMI >27). The stone clearance rate, operation time, duration of hospital stay, postoperative analgesic use, and postoperation complications were compared among groups. The categorical variable was analyzed by Chi-square test, and the continuous variable was analyzed by Kruskal–Wallis test. The possible prognosticators for stone clearance were also analyzed using logistic regression method. Results: There were no significant differences among groups in terms of age, gender, stone character, stone size, and laterality. A higher proportion of hypertension was observed in the larger BMI groups and lower hemoglobin level in the smaller BMI group. No significant differences of stone clearance rate (66%, 76%, 70% in normal size, overweight, and obesity groups, respectively), duration of hospital stay, postoperative analgesic use, and complication rate were identified among groups. The most common complication was postoperative fever in overweight and obesity groups. Multivariable analysis showed the stone character was a significant prognosticator for stone clearance. Conclusion: BMI did not reveal the impact on the stone clearance, operative time, duration of hospital stay, postoperative analgesic requirement, and postoperative complication in patients undergoing PCNL.