Metabolic risk factors in patients with struvite stone

• Grant number: 16/17398-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2016
• End date: October 31, 2017
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Alexandre Danilovic
• Grantee: Isabela Akemi Wei
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Urolithiasis is the second most common cause of nephrectomy. Loss of renal function because of obstruction or infection is the most prevalent cause for nephrectomy in these patients. However, patients submitted to nephrectomy due to struvite stones may also have metabolic risk factor for calcium or uric acid stones that may lead to recurrence of stones in the remaining kidney. Objective: This research aims to evaluate the metabolic risk factors incidence for urolithiasis in patients submitted to nephrectomy as a result of magnesium ammonium phosphate stones and the impact on renal function due to recurrence of stones in the remaining kidney. Methods: Electronic charts of 156 patients submitted to nephrectomy due to urolithiasis between 2006 and 2013 at our Institution will be retrospectively evaluated. All patients will be analyzed by their gender, age, pre existence of comorbidities suchlike diabetes mellitus, systemic arterial hypertension and dyslipidemia, pre operative serum creatinine, serum creatinine 3, 6 , 12 months and in the last medical appointment after nephrectomy and metabolic risk factors for urolithiases such as hypercalciuria (>300 mg/24h), hypocitraturia (<300 mg/24h), hypernatriuria (>220mEq/24h), hyperoxaluria (>40 mg/24h), hyperuricosuria (>750 mg/24h), hypercystinuria (>67 mg/24h), hyperuricemia (>45 mg/dL), hypercalcemia (>10,2 mg/dL), PTH (10-65 pg/mL), serum and urinary pH and average urine flow rates from at least two samples will be analyzed so an association can be identified between metabolic risk factors and struvite stones in these patients. The comorbities will be classified according to the Charlson Comorbidity Index and the ASA Classification (American Society of Anesthesiologists). The Glomerular Filtration Rate (GFR), estimated by the Modification of Diet in Renal Disease (MDRD), stable for over 60 days will be used de determine the chronic renal disease stage. The stratification of the renal stage will be made according to The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI) stratification. A multivariate logistic regression model will be used to identify the recurrence of urolithiasis in the remaining kidney predictors. (AU)