Dyslipidemia and kidney stone risk.

OBJECTIVE

We studied the impact of dyslipidemia on 24-hour urinalysis and stone composition.

METHODS

We retrospectively identified patients with nephrolithiasis who underwent 24-hour urinalysis and lipid profile evaluation within 3 months. Patients were divided into groups based on total cholesterol, high density lipoprotein, nonhigh density lipoprotein and triglycerides. The groups were compared based on demographic data, diabetes, hypertension and each component of 24-hour urinalysis and stone composition. Multivariate analysis and linear regression were performed to control for potential confounders, including age, gender, body mass index, diabetes and hypertension.

RESULTS

A total of 2,442 patients with a mean age of 51.1 years were included in study. On multivariate analysis patients with high total cholesterol had significantly higher urinary potassium and calcium, those with low high density lipoprotein or high triglycerides had significantly higher urinary sodium, oxalate and uric acid with lower pH, and those with high nonhigh density lipoprotein had higher urinary sodium and uric acid. Regarding stone composition, high total cholesterol and triglycerides were significantly associated with a higher uric acid stone rate (p = 0.006 and <0.001, respectively). Linear regression showed a significant association of nonhigh density lipoprotein with higher urinary sodium (p = 0.011) and uric acid (p <0.001) as well as triglycerides and higher uric acid (p = 0.017), and lower urinary pH (p = 0.005).

CONCLUSIONS

There is a link between dyslipidemia and kidney stone risk that is independent of other components of metabolic syndrome such as diabetes and obesity. Specific alterations in the patient lipid profiles may portend unique aberrations in urine physicochemistry and stone risk.