Obesity, Diabetes May Elevate Risk of Kidney Stones

The prevalence of kidney stone disease is increasing alongside the spread of obesity, type 2 diabetes mellitus (T2DM), and metabolic syndrome (MetS).

To investigate the potential associations among the presence and severity of T2DM, glycemic control, and insulin resistance (IR) with kidney stone disease, researchers at Stanford University in California performed a cross-sectional analysis of all adult participants in the 2007—2010 National Health and Nutrition Examination Survey (NHANES).

The patients included in the analysis had a self-reported history of kidney stone disease, T2DM, T2DM-related medication usage, and diabetic comorbidity. The researchers estimated IR using fasting plasma insulin (FPI) levels, and they classified glycemic control through glycosylated hemoglobin A1c (HbA1c) and fasting plasma-glucose levels (FPG). Their findings were adjusted for age, sex, race/ethnicity, smoking history, body mass index (BMI), laboratory values, and MetS components.

The analysis found patients who reported a history of T2DM and insulin use had a more than double risk of developing kidney stones. Those with FPG levels 100—126 mg/dL and >126 mg/dL also had increased odds of having kidney stones, though elevated HbA1c bore the strongest association with kidney stone disease. Because this study was cross-sectional in design and all data was self-reported by patients, causal inference was limited.

The researchers estimated 43% of the roughly 3.1 million kidney stone episodes among US diabetics are related to T2DM, while another 680,000 cases may result from poor glycemic control.

“Our study suggests that the severity of T2DM — as measured by glycemic control and IR — is an important risk factor for kidney stone disease,” the authors concluded. “Future studies comparing treatment strategies in T2DM should aim to include kidney stones as an outcome of interest to test the hypotheses.”