Response to Dietary Oxalate after Bariatric Surgery

Response to Dietary Oxalate after Bariatric Surgery

Author Froeder, Leila Autor UNIFESP Google Scholar
Arasaki, Carlos Haruo Autor UNIFESP Google Scholar
Malheiros, Carlos Alberto Google Scholar
Baxmann, Alessandra Calabria Autor UNIFESP Google Scholar
Heilberg, Ita Pfeferman Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Santa Casa Med Sch
Abstract Background and objectives Bariatric surgery (BS) may be associated with increased oxalate excretion and a higher risk of nephrolithiasis. This study aimed to investigate urinary abnormalities and responses to an acute oxalate load as an indirect assessment of the intestinal absorption of oxalate in this population.Design, setting, participants, & measurements Twenty-four hour urine specimens were collected from 61 patients a median of 98 months after BS (post-BS) as well as from 30 morbidly obese (MO) participants; dietary information was obtained through 24-hour food recalls. An oral oxalate load test (OLT), consisting of 2-hour urine samples after overnight fasting and 2, 4, and 6 hours after consuming 375 mg of oxalate (spinach juice), was performed on 21 MO and 22 post-BS patients 12 months after BS. Ten post-BS patients also underwent OLT before surgery (pre-BS).Results There was a higher percentage of low urinary volume (<1.5 L/d) in post-BS versus MO (P<0.001). Hypocitraturia and hyperoxaluria (P=0.13 and P=0.36, respectively) were more frequent in BS versus MO patients. the OLT showed intragroup (P<0.001 for all periods versus baseline) and intergroup differences (P<0.001 for post-BS versus MO; P=0.03for post-BS versus pre-BS). the total mean increment in oxaluria after 6 hours of load, expressed as area under the curve, was higher in both post-BS versus MO and in post-BS versus pre-BS participants (P<0.001 for both).Conclusions the mean oxaluric response to an oxalate load is markedly elevated in post-bariatric surgery patients, suggesting that increased intestinal absorption of dietary oxalate is a predisposing mechanism for enteric hyperoxaluria. Clin J Am Soc Nephrol 7: 2033-2040, 2012. doi: 10.2215/CJN.02560312
Language English
Sponsor Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Grant number FAPESP: 2008/022794
CNPq: 475681/2007-0
Date 2012-12-01
Published in Clinical Journal of the American Society of Nephrology. Washington: Amer Soc Nephrology, v. 7, n. 12, p. 2033-2040, 2012.
ISSN 1555-9041 (Sherpa/Romeo, impact factor)
Publisher Amer Soc Nephrology
Extent 2033-2040
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000312111400018

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