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Cystatin C measurement leads to lower metformin dosage in elderly type 2 diabetic patients
Author(s) -
Šálek Tomáš,
Adamíková Alena
Publication year - 2019
Publication title -
basic and clinical pharmacology and toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.805
H-Index - 90
eISSN - 1742-7843
pISSN - 1742-7835
DOI - 10.1111/bcpt.13132
Subject(s) - cystatin c , medicine , renal function , metformin , creatinine , kidney disease , urology , dosing , diabetes mellitus , type 2 diabetes mellitus , type 2 diabetes , epidemiology , endocrinology
The aim of this study was to provide evidence for the hypothesis that estimated glomerular filtration rate from serum Cystatin C ( eGFR cys) is better to be determined for all elderly type 2 diabetes mellitus (T2 DM ) patients based on eGFR cys upward and downward reclassification rate for hypothetical metformin dose reduction by eGFR cys at the GFR decision point of 45 mL /min/1.73 m 2 . A total of 265 consecutive T2 DM elderly patients (age range 65‐91 years) from outpatient diabetic clinic were included in the study. The Kidney Disease Improving Global Outcomes ( KDIGO ) guidelines for metformin dosing were strictly followed. Estimated glomerular filtration rate from serum creatinine ( eGFR crea) led to results of metformin eligibility. Each of the results of eGFR crea‐based eligibility was further compared to eGFR cys‐based eligibility. Creatinine was measured by enzymatic method standardized against international reference material SRM 967. Cystatin C was determined by method traceable to DA ERM 471 international standard. eGFR crea and eGFR cys were calculated according to Chronic Kidney Disease Epidemiology Collaboration ( CKD ‐ EPI ) equations. A downward reclassification rate was higher than upward reclassification rate (31 vs 3, respectively; P < 0.0001). The median ( IQR ) eGFR crea was higher than eGFR cys (73 (58‐85) vs 63 (50‐75) mL /min/1.73 m 2 , respectively; P < 0.0001). eGFR cys reclassified significant proportion of patients with T2 DM from metformin eligible CKD stages to less or non‐eligible stages. The downward reclassification was more frequent in patients older than 80 years ( P < 0.01). Cystatin C‐based eGFR selects more complicated patients, where lower doses of metformin are possibly advisable. We recommend calculating both eGFR crea and eGFR cys for metformin dosing in elderly patients with T2DM.