Laparoscopic sleeve gastrectomy prevents the deterioration of renal function in morbidly obese patients over 40 years.

BACKGROUND: Chronic kidney disease (CKD) risk has been associated with elevated body mass index (BMI), especially in morbidly obese subjects. Aging and obesity can play a synergic effect on accelerating the renal function deterioration. Bariatric surgery (mainly gastric bypass or biliopancreatic diversion) has demonstrated an improvement on renal function, but little is known about the potential effect of sleeve gastrectomy on renal function.
METHODS: A prospective observational study was performed. Between 2009 and 2013, 50 morbidly obese patients over 40 years underwent a laparoscopic sleeve gastrectomy (LSG) at our institution. Renal function was evaluated by serum creatinine, urea, and estimated glomerular filtration rate (eGFR), calculated using the MDRD-4 formula. All the variables were obtained at three times: on the first visit to the surgeon's office (baseline), the day before surgery (preoperative), and 12 months after surgery.
RESULTS: Fifty patients underwent a LSG, 44 females (88%) and 6 males (12%), with a mean age 49.2 ± 6.4 years and mean BMI of 48.4 ± 7.7 kg/m(2). MDRD-4 values presented a significant reduction (69.4 ml/min/m(2) at baseline vs 62.5 ml/min/m(2) preoperatively; CI95% (2.2-11.3 ml/min/m(2)); p = 0.01). Comparing pre- and postoperative values, a significant reduction could be determined in creatinine (0.89 mg/dl preoperatively vs 0.71 mg/dl postoperatively; p = 0.01), urea (36.1 mg/dl preoperatively vs 29.8 mg/dl postoperatively; p = 0.023), and a significant increase in MDRD-4 (62.5 ml/min/m(2) preoperatively vs 77.6 ml/min/m(2) postoperatively; p < 0.001).
CONCLUSION: In patients over 40 years, renal function is going to deteriorate as long as the excess of weight persists. Laparoscopic sleeve gastrectomy has shown to improve the renal function 12 months after surgery.