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Abstract: PO0602

Effect of Hydroxycitrate (HCA) on Urine Chemistry in Calcium Kidney Stone Formers

Session Information

Category: Bone and Mineral Metabolism

  • 402 Bone and Mineral Metabolism: Clinical

Authors

  • Goldfarb, David S., NYU Langone Health, New York, New York, United States
  • Rohit, Kumar, Salem Health, Salem, Oregon, United States
  • Adiga, Avinash Govinda, University of Alabama, Tuscaloosa, Alabama, United States
  • Norris, Briony L., The Royal Melbourne Hospital, Melbourne, Victoria, Australia
  • Yang, Lee, LithoLink Corp, Chicago, Illinois, United States
  • Modersitzki, Frank, NYU Langone Health, New York, New York, United States
  • Bushinsky, David A., University of Rochester Medical Center, Rochester, New York, United States
  • Rimer, Jeffrey D., University of Houston, Houston, Texas, United States
  • Asplin, John R., LithoLink Corp, Chicago, Illinois, United States
Background

Potassium citrate is a mainstay of treatment to prevent recurrent calcium-containing kidney stones. However, it can increase urine pH and calcium phosphate (CaP) supersaturation (SS). HCA, extracted from Garcinia cambogia, is a potent inhibitor of calcium oxalate crystal growth in vitro and should not provide “potential base”, as citrate does. Urine excretion of HCA has not been well-studied.

Methods

We enrolled 2 groups: calcium stone formers (SF; n = 9) and non-stone forming (NSF, n = 9) controls (after excluding 2 SF and 2 NSF whose urine creatinine excretion on the 2 collections differed by more than 20%). Mean age 49.3 years. Thiazides and citrate were held for 2 weeks prior to study. Participants recorded a self-selected diet for 2 days and performed 24-hour urine collection on day 2. HCA was purchased online from Amazon.com (Super CitriMax Garcinia Cambogia); 2 caps = 900 mg of HCA. Participants took 900 mg 3 times daily orally for 7 days. Diet from days 1 and 2 was replicated on day 6 and 7 of the HCA arm of the study. 24-hour urine was collected on day 7. Urine was sent to Litholink, Inc. (Chicago, IL) for analysis. Urinary excretion of hydroxycitrate and citrate were measured using LC/MS.

Results

According to label, 6 pills would provide 2700 mg (13.2 mmol) of HCA per day; we measured content as 3198 mg (15.6 mmol). Citrate content is supposed to be 0, but we found 126 mg (0.66 mmol) per day. Both NSF and SF had appearance of HCA in the urine: 1.86 + 0.80 and 2.07 + 0.67 mmol/day (p = 0.56). Urine chemistry seen in Table 1. In NSF, pH and citrate did not change. In SF, pH increased, citrate did not. K went up in both groups.

Conclusion

Administration of HCA, a potential inhibitor of Ca stone formation, leads to significant urinary HCA excretion. Citrate excretion was not affected. Urine pH increased, suggesting some alkalinizing effect. The difference in NSF and SF may be due to the lower starting pH in SF. The effect of HCA on stone formation remains to be determined.

Urinary chemistry after HCA
 Baseline NSFHCA NSFp-valueBaseline SFHCA SFp-value
pH6.67 +/- 0.626.63 +/- 0.500.875.81 +/- 0.576.32 +/- 0.570.007
Citrate (mg/d)677 +/- 189662 +/- 1710.67520 +/- 288697 +/- 3300.12
K (meq/d)63 +/- 1981 +/- 100.00870 +/- 20100 +/- 270.003

Funding

  • Clinical Revenue Support