Comparative study of 24-h and fasting urine pH evaluation in patients with urinary lithiasis using potassium citrate

• Grant number: 13/18584-9
• Support Opportunities: Regular Research Grants
• Start date: February 01, 2014
• End date: April 30, 2015
• Field of knowledge: Health Sciences - Medicine
• Principal Investigator: Paulo Roberto Kawano
• Grantee: Paulo Roberto Kawano
• Host Institution: Faculdade de Medicina (FMB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Associated researchers: Carmen Regina Petean Ruiz Amaro ; João Luiz Amaro

Abstract

The prevalence of urinary tract lithiasis (UTL) varies from 1 to 20%, depending on the diagnostic method used; and it has been increasing worldwide, with recurrence rates of 50% after 10 years and 75% after 20 years of the first episode. Classically, analysis of calculi composition and physicochemical properties of 24-hour urine samples are considered the most important auxiliary tools in the investigation and identification of etiologic factors of UTL. However, recent research suggests that the urinary pH determination in fasting urine samples could be as accurate as the dosage usually performed in 24-hour urine samples. Objective: To compare urinary pH determinations in a single fasting urine sample with the 24-hour urine, in order to standardize the optimal methodology for monitoring the urinary pH in patients with urolithiasis in use of potassium citrate. Patients and methods: We will prospectively evaluate 130 patients with urolithiasis followed at the Ambulatório de Metabolismo do HCFMB - UNESP. Patients over 18 years-old, with a CT-confirmed diagnosis of UTL and receiving treatment with potassium citrate, will be included (Group 1). Recurrent urinary tract infection, chronic antibiotic therapy and creatinine clearance <60 ml / min will be exclusion criteria. For the urinary pH analysis, two different methodologies will be employed: classical analysis by pH test tape and digital pH-meter reading. In order to better evaluate the urinary pH in normal people, 20 healthy volunteers older than 18 years-old (not suffering from kidney stones or other comorbidities) will be evaluated with the same proposed methodology. In both groups, demographic data such as age, gender, weight, height and body mass index (BMI) will be analyzed. Additionally, in group 1, further data regarding the main disease and related concomitant pathologies will be considered. (AU)