436 - Bariatric Surgery and Kidney-Related Outcomes

Bariatric Surgery and Kidney-Related Outcomes Alex R. Chang 1 , 2 , Morgan E. Grams 3 , 4 and Sankar D. Navaneethan 5 , 6 1 Kidney Health Research Institute, Geisinger Health System, Danville, Pennsylvania, USA; 2 Department of Epidemiology and Health Services Research, Geisinger Health System, Danville, Pennsylvania, USA; 3 Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University, Baltimore, Maryland, USA; 4 Divison of Nephrology, Johns Hopkins Uni- versity, Baltimore, Maryland, USA; 5 Selzman Institute for Kidney Health, Section of Nephrology, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA; and 6 Section of Nephrology, Michael E. DeBakey Veterans Affairs Medical Center, Houston, Texas, USA The prevalence of severe obesity in both the general and the chronic kidney disease (CKD) populations continues to rise, with more than one- fi fth of CKD patients in the United States having a body mass index of $ 35 kg/m 2 . Severe obesity has signi fi cant renal consequences, including increased risk of end-stage renal disease (ESRD) and nephrolithiasis. Bariatric surgery represents an effective method for achieving sustained weight loss, and evidence from randomized controlled trials suggests that bariatric surgery is also effective in improving blood pressure, reducing hyperglycemia, and even inducing diabetes remis- sion. There is also observational evidence suggesting that bariatric surgery may diminish the long-term risk of kidney function decline and ESRD. Bariatric surgery appears to be relatively safe in patients with CKD, with postoperative complications only slightly higher than in the general bariatric surgery popula- tion. The use of bariatric surgery in patients with CKD might help prevent progression to ESRD or enable selected ESRD patients with severe obesity to become candidates for kidney transplantation. However, there are also renal risks in bariatric surgery, namely, acute kidney injury, nephrolithiasis, and, in rare cases, oxalate nephropathy, particularly in types of surgery involving higher degrees of malabsorption. Although bariatric surgery may improve long-term kidney outcomes, this potential bene fi t remains un- proved and must be balanced with potential adverse events. Kidney Int Rep (2017) 2, 261 – 270; http://dx.doi.org/10.1016/j.ekir.2017.01.010 KEYWORDS: bariatric surgery; glomerular fi ltration rate; kidney; morbid obesity; obesity ª 2017 International Society of Nephrology. Published by Elsevier Inc. This is an open access article under the CC BY- NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). W orldwide, the prevalence of obesity (body mass index [BMI] $ 30 kg/m 2 ) in the general popu- lation has risen dramatically over the past few decades; this trend is paralleled in the chronic kidney disease (CKD) population. 1,2 Among adults with CKD in the United States, for example, the prevalence of obesity increased from 38.1% in 1999 to 2002 to 44.1% in 2011 to 2014 ( P ¼ 0.004 for linear trend) ( Figure 1 ). 2 The increase in obesity prevalence occurred primarily in World Health Organization (WHO) class II and III obesity 3 (BMI $ 35 and $ 40 kg/m 2 , respectively), which increased from 17.2% in 1999 to 2002 to 22.2% in 2011 to 2014 ( P ¼ 0.01 for linear trend). An increasing prevalence of obesity in the CKD population is of particular concern due to evidence of associations between higher BMI and adverse renal outcomes. In observational studies, obesity has been associated with higher risk of incident CKD and end-stage renal disease (ESRD), as well as neph- rolithiasis and renal cell cancer. 4 – 7 Potential mecha- nisms explaining the increased risk for CKD and ESRD include obesity-mediated hypertension, insulin resis- tance, glomerular hyper fi ltration, activation of the renin � angiotensin � aldosterone system, in fl ammation, and adipocytokine dysregulation. 8,9 On the other hand, the risk associated with obesity may be reversible: a randomized controlled trial of patients with type 2 diabetes demonstrated that weight loss decreased the risk of adverse CKD outcomes. 10 However, achieving sustained weight loss through lifestyle modi fi cation is challenging. Bariatric surgery is a proven, effective method for sustained weight loss and is becoming more common- place for patients with morbid or severe obesity. Consensus guidelines from a National Institutes of Health (NIH) conference include BMI $ 40 kg/m 2 or BMI $ 35 kg/m 2 with obesity-related comorbidity as approved clinical indications for bariatric surgery. 11 As a signi fi - cant proportion of patients with CKD may qualify for Correspondence: Alex R. Chang, 100 N Academy Avenue, Danville, Pennsylvania 17822, USA. E-mail: achang@geisinger. edu Received 23 January 2017; accepted 23 January 2017; published online 26 January 2017 Kidney International Reports (2017) 2, 261 – 270 261 WORLD KIDNEY DAY MINI SYMPOSIUM ON KIDNEY DISEASE AND OBESITY APRIL 2020 | The Surgical Technologist | 159