ORLANDO, FL USA (UroToday.com) - There is a known association between hypertension (HTN) and nephrolithiasis. Abnormalities in renal calcium metabolism in hypertensive patients can lead to increased urinary calcium excretion. The research group sought to evaluate differences in 24-hour urine parameters between patients with and without HTN in a large cohort of stone formers.
This retrospective study consisted of patients with a 24-hour urinalysis (Litholink®) available, and a history of HTN in the demographic data. Univariate t test and multivariate analysis were performed comparing the 24-hour urinalysis profiles of patients with HTN to that of normotensive patients.
A total of 1 115 patients were included, 442 (40%) had HTN and 673 (60%) did not. Univariate analysis revealed significantly greater urine sodium and potassium (p < 0.05), and significantly lower urine pH, calcium, supersaturation (SS) of calcium oxalate (CaOx) and SS calcium phosphate (all p < 0.05) in hypertensive patients. Multivariate analysis showed significantly lower calcium (mean difference=-20.13), citrate (-74.04), phosphate (-0.043), and SS CaOx (-0.648) in patients with HTN.
The research group showed significant lowered 24-hour urine calcium and SS CaOx in hypertensive patients on both univariate and multivariate analyses. In addition, they demonstrated significantly lower 24-hour urine citrate on multivariate analysis.
In conclusion, lower levels of stone inhibitors such as citrate may play a greater role in stone formation in patients with hypertension than deranged calcium metabolism. This finding might help the mitigation of nephrolithiasis in hypertensive patients.
Presented by Christopher Hartman, MD at the American Urological Association (AUA) Annual Meeting - May 16 - 21, 2014 - Orlando, Florida USA
New Hyde Park, NY USA
Written by Achim Lusch, MD, University of California (Irvine), and medical writer for UroToday.com