The effect of obesity on perioperative outcomes following percutaneous nephrolithotomy.

Research paper by Vincent V Trudeau, Pierre I PI Karakiewicz, Katharina K Boehm, Paolo P Dell'Oglio, Zhe Z Tian, Alberto A Briganti, Shahrokh F SF Shariat, Luc L Valiquette, Naeem N Bhojani

Indexed on: 04 Jun '16Published on: 04 Jun '16Published in: Journal of endourology / Endourological Society


Objectives To test if obesity predisposes to higher rates of adverse outcomes after percutaneous nephrolithotomy (PCNL). Material and Methods Within the Nationwide Inpatient Sample (NIS), we identified patients treated with PCNL between 1998-2010 for kidney stones. We examined the temporal trends in PCNL use and charges among obese and non-obese patients. We then tested the effect of obesity on perioperative complications, transfusions, length of stay (LOS) and total hospital charges (THC). LOS and THC were defined as a continuous variable and were also dichotomized according to the 75th percentile into prolonged LOS (pLOS) and increased THC (iTHC). Then, multivariable models were fitted. Results Overall, a weighted sample of 90 529 individuals treated with PCNL between 1998-2010 was examined. Of those patients, 9 300 were obese (10.3%). The proportion of PCNLs performed in obese patients increased throughout the years from 7.4 to 16.7% (p<0.001). Overall complication rates were 21.6 vs. 22.0% (p=0.3) and transfusion rates were 4.3 vs. 4.0% (p=0.1) for obese and non-obese patients, respectively. Obese patients had fewer genitourinary complications (13.4 vs 15.0%, p<0.001), but had higher rates of sepsis (1.7 vs 1.3%, p=0.009) as well as respiratory (3.0 vs 2.5%, p=0.002) and vascular complications (0.3 vs 0.2%, p=0.007). Conversely, pLOS (20.9 vs. 18.8%, p<0.001) and iTHC (30.8 vs 24.4%, p<0.001) were more frequently recorded in obese patients. In multivariable analyses, obesity was not associated with higher rates of overall complications (odds ratio (p= 0.3) nor with higher rates of transfusions (p=0.3). However, obesity was associated with pLOS (OR: 1.21, p=0.002), as well as iTHC (OR: 1.17, p=0.002). Conclusions PCNL in obese patients did not result in higher rates of individual complications or transfusions. However, it resulted in higher rates of pLOS and iTHC.

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