Recent and persistent hyponatremia are associated with an increased risk of kidney stones, according to investigators.
Naoto Tominaga, MD, PhD, of Georgetown University Medical Center in Washington, D.C., and colleagues compared 20,199 patients with kidney stones (cases) and 20,199 patients without kidney stones (controls) matched by age, sex, race, and encounter window. Compared with patients without a history of hyponatremia, those with recent and persistent hyponatremia had significant 2.0- and 6.2-fold increased odds of kidney stones, respectively, Dr Tominaga’s team reported online in PLOS One.
Based on prior research findings, Dr Tominaga’s team stated that increased urine calcium excretion is a potential common link between hyponatremia and kidney stones.
The study is the first to demonstrate an association between hyponatremia and kidney stones in a large US health system, according to the researchers.
The investigators analyzed patient data extracted from the MedStar Health system database, which contained more than 3.4 million unique patient records as of March 2016. Cases and controls had a mean age of 43.6 years. The groups were 48.7% female and 61.4% white. The mean encounter window was 1304 days.
Patients considered to have recent hyponatremia had at least 1 serum sodium level of less than 135 mEq/L within 30 days before the end of the encounter window. Patients classified as having persistent hyponatremia had at least 1 serum sodium level of less than 135 mEq/L within 30 days before the end of the encounter window and at least 2 serum sodium measurements of less than 135 mEq/L at least 1 year apart until 30 days before the end of the encounter window during the encounter window.
Tominaga N, Fernandez SJ, Mete M, et al. Hyponatremia and the risk of kidney stones: A matched case-control study in a large US health system. PLoS One. 2018;13(9):e0203942.