Login to Access Video or Poster Abstract: MP12-07
Sources of Funding: None

Introduction

Gastric bypass surgery for obesity is known to be associated with post-operative hyperoxaluria, which can lead to urolithiasis and kidney damage. The objective of this study was to determine if markers of kidney injury correlated with urinary oxalate excretion. If so, such biomarkers might be early predictors of oxalate nephropathy.

Methods

Patients were recruited from 4 large academic centers > 6 months following completion of gastric bypass surgery. Patients provided a spot urine sample for analysis of three markers of kidney injury: 8-iso-Prostaglandin F2α, N-acetyl-β-D-Glucosaminidase, and Neutrophil gelatinase-associated lipocalin. Patients also provided 24 hour urine samples for stone risk analysis.

Results

46 study patients provided samples and the average age was 48.4 + 11.3. There were 40 women and 6 men. There was no difference in the level of any of the three inflammatory markers between the study group and the reference range generated from healthy non-hyperoxaluric subjects. Neither oxalate excretion nor supersaturation of calcium oxalate correlated with any of the injury markers There was no difference noted between those with hyperoxaluria (N=17) and those with normoxaluria (N=29) with respect to any of the injury markers (Table 1).

Conclusions

Though hyperoxaluria was common after bypass surgery, markers of kidney injury were not elevated after surgery. No correlation was found between urine oxalate excretion and any of the injury markers.

Funding

None