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Kidney Week

Abstract: SA-PO691

Characterization of a Cohort with Kidney Stones and Enteric Hyperoxaluria

Session Information

Category: Fluid, Electrolytes, and Acid-Base Disorders

  • 1102 Fluid, Electrolyte, and Acid-Base Disorders: Clinical

Authors

  • Ro, Han, Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States
  • Tatton, Ryan, Mayo Clinic, Scottsdale, Arizona, United States
  • O'Neill, Stephen Raul, Mayo Clinic, Scottsdale, Arizona, United States
  • Mehta, Ramila A., Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States
  • Lieske, John C., Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States
  • Keddis, Mira T., Mayo Clinic, Scottsdale, Arizona, United States
Background

Enteric hyperoxaluria (EH) is a risk factor for kidney stones. The relationship between risk factors and the natural history remains poorly defined. To address this knowledge gap, we created an EH patient registry.

Methods

The electronic medical record at all 3 Mayo Clinic sites was searched to identify patients with a known cause of EH, 24-hour urine oxalate (Uox) ≥40mg, and history of kidney stones. Symptomatic stone events were defined by the presence of renal colic, stone passage associated with urinary tract infection or hematuria, or procedure for stone removal.

Results

We report on data from the first 74 abstracted patients. The largest group of 34 (46%) had bariatric surgery (29 (85%) of these were Roux En-Y Gastric Bypass (RYGB)), 20 (28%) inflammatory bowel disease (IBD), 11 (15%) pancreatic insufficiency, 5 (7%) short bowel syndrome, 1 (1%) celiac, and 1 (1%) other fat malabsorptive conditions. Mean age at first stone diagnosis was 48.6 ±14.1 years and BMI 31.6±8.71 kg/m2. EH diagnosis was on average 8 years after first stone event and mean UOx was 65.3±30.9 mg/24 hr. Follow-up after EH diagnosis was available for 60/74 patients, 78% of whom had a prior stone event (average n=4, 45%>2 events). Those with bariatric surgery were more likely to be female (p=0.002), have a higher BMI (p<0.001), and experience asymptomatic kidney stones before surgery (p=0.02). After a median follow-up of 3 years, the 5-year cumulative stone event rate after EH diagnosis was 52.9% (Figure) and did not differ by EH cause.

Conclusion

EH patients experience a high rate of stone recurrence of up to 53% at 5 years regardless of underlying etiology. RYGB is the single most common cause, however other conditions associated with fat malabsorption are also common. These preliminary data strongly support continued efforts to develop a robust EH patient registry to identify specific phenotypic features that are associated with stone disease risk to inform study design for novel therapeutics.