Diabetic Severity and Risk of Kidney Stone Disease

BackgroundThe prevalence of kidney stone disease is rising along with increasing rates of obesity, type 2 diabetes mellitus (T2DM), and metabolic syndrome.ObjectiveTo investigate the associations among the presence and severity of T2DM, glycemic control, and insulin resistance with kidney stone disease.Design, setting, and participantsWe performed a cross-sectional analysis of all adult participants in the 2007–2010 National Health and Nutrition Examination Survey (NHANES). A history of kidney stone disease was obtained by self-report. T2DM was defined by self-reported history, T2DM-related medication usage, and reported diabetic comorbidity. Insulin resistance was estimated using fasting plasma insulin (FPI) levels and the homeostasis model assessment of insulin resistance (HOMA-IR) definition. We classified glycemic control using glycosylated hemoglobin A1c (HbA1c) and fasting plasma-glucose levels (FPG).Outcome measurements and statistical analysisOdds ratios (OR) for having kidney stone disease were calculated for each individual measure of T2DM severity. Logistic regression models were fitted adjusting for age, sex, race/ethnicity, smoking history, and the Quételet index (body mass index), as well as laboratory values and components of metabolic syndrome.Results and limitationsCorrelates of kidney stone disease included a self-reported history of T2DM (OR: 2.44; 95% confidence interval [CI], 1.84–3.25) and history of insulin use (OR: 3.31; 95% CI, 2.02–5.45). Persons with FPG levels 100–126 mg/dl and >126 mg/dl had increased odds of having kidney stone disease (OR 1.28; 95% CI, 0.95–1.72; and OR 2.29; 95% CI, 1.68–3.12, respectively). Corresponding results for persons with HbA1c 5.7–6.4% and ≥6.5% were OR 1.68 (95% CI, 1.17–2.42) and OR 2.82 (95% CI, 1.98–4.02), respectively. When adjusting for patient factors, a history of T2DM, the use of insulin, FPI, and HbA1c remained significantly associated with kidney stone disease. The cross-sectional design limits causal inference.ConclusionsAmong persons with T2DM, more-severe disease is associated with a heightened risk of kidney stones.