Kidney stones are common after bariatric surgery John C. Lieske, Ramila A. Mehta, Dawn S. Milliner, Andrew D. Rule, Eric J. Bergstralh, Michael G. Sarr  Kidney International  Volume 87, Issue 4, Pages 839-845 (April 2015) DOI: 10.1038/ki.2014.352 Copyright © 2015 International Society of Nephrology Terms and Conditions

Figure 1 Risk of new-onset nephrolithiasis after bariatric surgery. The risk of incident stones was greater after Roux-en-Y gastric bypass (RYGB) or malabsorptive bariatric procedures, compared with that in matched obese controls (P<0.001 overall). Patients with restrictive procedures were not at increased risk. Kidney International 2015 87, 839-845DOI: (10.1038/ki.2014.352) Copyright © 2015 International Society of Nephrology Terms and Conditions

Figure 2 Risk of new-onset chronic kidney disease (CKD) after bariatric surgery. The risk of incident CKD was greater after malabsorptive bariatric procedures compared with that in matched obese controls (P=0.004 overall). Patients were not at increased CKD risk after Roux-en-Y gastric bypass (RYGB) or restrictive procedures. Kidney International 2015 87, 839-845DOI: (10.1038/ki.2014.352) Copyright © 2015 International Society of Nephrology Terms and Conditions

Figure 3 Changes in urine oxalate and CaOx SS after surgery. (a) Urinary oxalate increased subtly in all cases over time after bariatric surgery (♦ solid diamonds, - - - - dashed line), and more dramatically in those who developed stones (Δ open triangles, ______ solid line). The mean urine oxalate was at the upper limit of the reference value (0.46mmol/day) at all time points in obese controls who developed stones (○ open circles, _. _. _. _ dash-dot line). (b) At all time points CaOx SS was highest in the post–bariatric-surgery patients who developed stones (Δ open diamonds, _____ solid line), but still at or above the reference mean (1.77 DG) in both obese controls with stones (○ open circles, _. _. _ dash-dot line) and in post–bariatric-surgery patients without stones (♦ solid diamonds, - - - - dashed line). Kidney International 2015 87, 839-845DOI: (10.1038/ki.2014.352) Copyright © 2015 International Society of Nephrology Terms and Conditions