The clinical research office of the endourological society percutaneous nephrolithotomy global study: Outcomes in the morbidly obese patient – a case control analysis

Abstract

Background: Efficacy and safety of percutaneous nephrolithotomy (PCNL) have been demonstrated in obese individuals. Yet, there is a paucity of data on the outcomes of PCNL in morbidly obese patients (body mass index [BMI] >40). Methods: Perioperative and stone-related outcomes following PCNL in morbidly obese patients was assessed using a prospective database administered by the Clinical Research Office of the Endourological Society (CROES). A multidimensional match of 97 morbidly obese patients with those of normal weight was created using propensity score matching. Student's t-test and Chi-square tests were used to assess for differences between the groups. Results: In total, 97 patients with a BMI >40 kg/m 2 were matched by stone characteristics with 97 patients of normal weight. The morbidly obese population demonstrated higher rates of diabetes mellitus (43% vs. 6%, p < 0.001) and cardiovascular disease (56% vs. 18%, (p < 0.001). Access was achieved more frequently by radiologists in the morbidly obese group (19% vs. 6%, p = 0.016). Mean operative duration was longer in the morbidly obese group (112 ± 56 min vs. 86 ± 43.5 min, p < 0.001). Stone-free rates were lower in the morbidly obese group (66% vs. 77%, p = 0.071). There was no significant difference in length of hospital stay or transfusion rate. Morbidly obese patients were significantly more likely to experience a postoperative complication (22% vs. 6%, p = 0.004). Interpretation: PCNL in morbidly obese patients is associated with longer operative duration, higher rates of re-intervention and an increased risk of perioperative complications. With this knowledge, urologists should seek to develop strategies to optimize the perioperative management of such patients.

Nephrolithiasis in the Obese Patient

“…A case-control analysis that matched 97 morbidly obese patients (BMI > 40 kg/m 2 ) with 97 normal-weight patients demonstrating a significant impact of BMI on PCNL outcomes [50]. This study showed that SFR decreased with an increase in BMI and this was associated with a higher risk of re-intervention.…”

Percutaneous nephrolithotomy in super obese patients (body mass index ≥ 50 kg/m2): overcoming the challenges

“…A number of mainly retrospective studies have evaluated PCNL outcomes in obese and morbidly obese patients, although to our knowledge there are no reports on outcomes in the super obese [9][10][11][12][24][25][26][27]. Interestingly, the definition of morbid obesity varies, with some studies using BMI ≥ 35 kg/m 2 as the threshold and others using BMI ≥ 40 kg/m 2 .…”

“…There is, however, less uniformity in the reported outcomes of complications, stone-free rates, operating times and need for auxiliary procedures. Results from the PCNL Global Study [10] and from Faerber and Goh [28] suggested a higher complication rate (22.1 vs 6.5%), lower stone-free rate (65.6 vs~79%), longer operating time (112 vs~80 min) and more frequent need for auxiliary procedures (28.1 vs 12.4%) in the morbidly obese vs normal weight patients [10,28]. This contrasts with a number of other retrospective studies, which found no significant association in these variables with BMI [9,11,12,26,27].…”

Percutaneous Nephrolithotomy in the Superobese: A Comparison of Outcomes Based on Body Mass Index

“…11 Several studies have documented the feasibility, safety, and efficacy of PCNL in obese patients. [12][13][14] However, limitations such as small sample size, 15 lack of comparator groups, 16,17 or few patients at BMI extremes 18 have led some experts to assert that alternative treatment modalities, namely flexible ureteroscopy, be considered first-line therapy. 19 Herein, we present our experience and outcomes following PCNL in patients across a wide range of BMI from a large, single-institutional contemporary dataset.…”