The effect of biliopancreatic diversion surgery on renal function--a retrospective study

BACKGROUND: The prevalences of obesity and chronic kidney disease (CKD) have increased simultaneously. Should a pathophysiological relationship exist between the two conditions, bariatric surgery and associated weight loss could be an important intervention in extremely obese individuals to slow the progression of CKD.

METHODS: We conducted a retrospective analysis of 25 patients who had undergone biliopancreatic diversion (BPD) surgery for extreme obesity (body mass index >40 kg/m(2)), with mean follow-up of 4 years. We assessed pre- and post-surgery renal function, body weight and blood pressure (BP) obtained from electronic hospital and primary care records.

RESULTS: There was a significant reduction in mean body weight at 4 years by 50.3 kg (SD = 20.65). The creatinine and estimated glomerular filtration rate (eGFR) also improved significantly: serum creatinine reduced by 16.2 μmol/l (SD = 19.57) while the eGFR improved by 10.6 ml/min/m(2) (SD = 15.45). The greatest improvement in eGFR was in the group (n = 7) with eGFR ≤60 ml/min/m(2). A subset of patients (n = 11) had evaluable BP readings and had a reduction in BP of 17/10 mmHg (SD = 33/12).

CONCLUSIONS: This retrospective study demonstrates a clinically significant improvement in renal function following BPD. Several mechanisms including weight loss could account for the positive impact on renal function. The physiology underlying this improvement requires further study.