Summary

Background:

The prevalence and etiology of nephrolithiasis vary, depending on geography, gender and ethnicity. 

Objectives:

To analyze the demographic data of return nephrolithiasis patients in a tertiary care center.

Methods:

We retrospectively reviewed our prospective registry database of return patients seen at our outpatient clinic for nephrolithiasis. Data included gender, age at first visit, age at first stone event, body mass index (BMI), self-reported hypertension, diabetes mellitus (DM), and hyperlipidemia. All patients were seen at least twice and had undergone a metabolic workup. 

Results:

A total of 260 return patients were seen during the period 2010–2015. The male:female ratio was 3.1:1. Mean age at the first stone event was 44.1 years. Median time elapsed since the first stone event to medical evaluation was 5 years (interquartile range 1–12 years). Hypertension was reported by 33.1% of the patients, DM by 23.5% and hyperlipidemia by 30.4%. All three diseases were reported by 11.5% of patients. The metabolic abnormalities detected were hypocitraturia (60%), low urine volume (LUV) (60%), hypercalciuria (40.8%), hyperoxaluria (24.2%), hyperuricosuria (16.5%) and hyperuricemia (13.5%). Stone compositions from most to least frequent were calcium-oxalate (81%), calcium-phosphate (11.9%) and uric acid (7.1%). We also found that 24.6% were obese (BMI ≥ 30 kg/m2) and showed higher rates of hypertension, DM, hyperlipidemia, hyperuricemia and hyperuricosuria compared with non-obese patients. Significantly higher rates of obesity and LUV were detected in females compared with males. Patients over age 45 had lower rates of hyperuricemia compared with patients ≥ 45 years old (P = 0.038).

Conclusions:

Factors related to nephrolithiasis can potentially differ among populations and countries. Our findings emphasize the significance of individualized national health programs to address local issues.