Urinary calculi and jejunoileal bypass operation. A long-term follow-up

Medical records of 56 patients who had undergone jejunoileal bypass (JIB) surgery because of morbid obesity were reviewed. The follow-up time varied from 3 to 25 years (average 16 years). Twenty-two of the 56 patients (39.3%) were found to have renal calculi. The interval between the operation and the occurrence or knowledge of the first stone formation ranged from some months to 19 years. The mean weight loss at 5 years was 36.5 kg. Renal function investigations showed no evidence that the jejunoileal bypass operation alters the renal function. The urinary excretion of oxalate was high: 1.112 mumol/24 h (normal range: 55-400 mumol/24 h), and citrate excretion was low: 1.48 mmol/24 h (normal range: 2-5 mmol/24 h). There was no difference in these respects between stone formers and non-stone formers.