Elevated blood glucose levels, even within the nondiabetic range, are associated with an increased risk of kidney stones in men, but not women, according to investigators.
Seolhye Kim, MD, MSc, of the Center for Cohort Studies, Total Healthcare Center, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea, and colleagues studied 278,628 Korean adults without nephrolithiasis who underwent a comprehensive health examination from 2011 to 2017. The investigators examined the association of glucose level, glycated hemoglobin level (HbA1c), and Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) with kidney stone development.
Kidney stones developed in 6904 participants during a median follow-up of 4.2 years. Among men, glucose levels of 90 to 99, 100 to 125, and 126 mg/dL or higher had were significantly associated with a 10%, 11% and 27% increased risk of kidney stones, respectively, compared with a glucose levels below 90 mg/dL after multivariable adjustment, the investigators reported in the American Journal of Kidney Diseases. An HbA1c of 6.0% to 6.4%, and 6.5% or higher were significantly associated with an 18% and 20% increased risk of kidney stones, respectively, compared with an HbA1c less than 5.7%. In addition, compared with men in the lowest HOMA-IR quintile, those in the highest quintile had a significant 18% increased risk of kidney stones.
“Although not fully understood, insulin resistance is one of several key pathophysiologic features underlying the association between glycemic dysregulation in the prediabetic stage and nephrolithiasis,” the authors wrote.
The study revealed no significant association between glycemic status and kidney stone risk among women. This finding may relate to the protective effects of estrogen, according to the investigators, who noted that most women in the study were premenopausal.
In their discussion of study limitations, the investigators pointed out that they were unable to consider dietary information, which can influence both glycemic status and stone formation. “Thus, we cannot exclude the possibility of some unmeasured or residual confounding factors in the association between glycemic status and nephrolithiasis risk.” In addition, they lacked data on stone composition, specific stone types, or urine chemistry. “Thus, we could not determine what type of nephrolithiasis was affected by glycemic status and insulin resistance.”
Kim S, Chang Y, Jung HS, et al. Glyemic status, insulin resistance, and the risk of nephrolithiasis: A cohort study [published online June 10, 2020]. Am J Kidney Dis. 2020.