The Effect of Disease Severity on 24-Hour Urine Parameters in Kidney Stone Patients with Type 2 Diabetes

Objective To characterize the changes in urine composition associated with increasing severity of diabetes, we analyzed urine composition relative to glycated hemoglobin (HbA1c) and treatment strategy in a largely minority population. Methods Patients treated for kidney stones between 2001 and 2013 at a single tertiary institution and had 24-hour urine collections were included in the study. Patients with type 1 diabetes or taking either thiazide diuretics or alkalinizing agents were excluded. Analysis was performed in IBM SPSS Statistics version 20 using multivariate regression, and Kruskal-Wallis testing was used. Results Nine hundred fifty-five patients were included in this study - 268 (28%) with type 2 diabetes mellitus, of whom 53 (19.8%) used insulin. Patients with diabetes had lower urine pH, calcium, and phosphate when compared with the control group, but no significant differences were found between the diabetes groups. Multivariate analysis found that HbA1c had a positive correlation with citrate (P =.008), creatinine (P =.037), urine volume (P =.044), and a trend toward a positive association with urinary calcium calcium (P =.064). Insulin use did not have a significant relationship with urinary parameters but trended toward an inverse relationship with calcium (P =.051). pH was not a significant predictor of any urine constituent. Conclusion In an ethnically diverse inner city patient population, patients with diabetes mellitus type 2 who use insulin have no significant differences in urine parameters when compared with those on oral hypoglycemics. Worsening glucose control as measured by HbA1c levels predicts increased urine citrate and volume.