Metabolic evaluation in urolithiasis – study of the prevalence of metabolic abnormalities in a tertiary centre

INTRODUCTION: Metabolic abnormalities are one of the most important risk factors for urinary stone disease. Our objective was to determine the prevalence of metabolic abnormalities in patients referred to the urolithiasis outpatient clinic of a tertiary centre. MATERIAL AND METHODS: We performed a cross-sectional study evaluating 67 patients referred to the urolithiasis outpatient clinic. Metabolic evaluation was performed, including one 24-hour urine sample. RESULTS: Metabolic abnormalities could be identified in 92.5% patients. Almost a quarter of the patients had only one metabolic abnormality and 67.6% had more than one abnormality. The most prevalent metabolic abnormalities were hypercalciuria (54.5%), hyperoxaluria (34.7%) and hyperuricosuria (32.3%). Patients with hypercalciuria were older (54.7 vs. 47.8 years, p = 0.018) and family history of stone disease was significantly more frequent among patients with hyperoxaluria (71.4% vs. 28.6%, p = 0.013). There was a positive linear relationship between body mass index (BMI) and urinary calcium (r = 0.247, p = 0.048) and a negative linear relationship between BMI and urinary pH (r = −0.254, p = 0.046). CONCLUSIONS: Given the high prevalence of metabolic abnormalities, metabolic evaluation should be performed in every patient with urolithiasis evaluated in a tertiary setting.