Common Measurement of Kidney Function Altered by Poor Glycemic Control

MedicalResearch.com Interview with:
Eiji Ishimura, MD, PhD, FASN, FACP
Osaka City University Hospital
Professor,Department of Nephrology
Osaka, JAPAN

MedicalResearch.com: What are the main findings of the study?

Dr. Ishimura: Poor glycemic control is a major factor in the overestimation of glomerular filtration rate (GFR) in diabetic patients. We found this simple conclusion by directly measuring GFR by use of inulin clearance. We have created new formulae to accurately assess the GFR in diabetic patients, with the correction of hemoglobin A1C (HbA1C) or glycated albumin (GA) as followings;

1)      eGFRcr corrected by HbA1c=eGFRcr / (0.428 + 0.085 × HbA1c)

2)      eGFRcr corrected by GA=eGFRcr / (0.525 + 0.028 × GA)


MedicalResearch.com: Were any of the findings unexpected?

Dr. Ishimura: All findings in our study were unexpected. Previously, most of nephrologists and diabetologists have known that eGFR in diabetic pateints are inaccurate. Unexpectedly, we found the major reason of inaccuracy of eGFR was the single factor of poor glycemic control. Simple correction of eGFR by hemoglobin A1C levels or glycated albumin levels was found to lead corrected eGFR values to very useful, feasible, accurate values of measured GFR (inulin clearance).

MedicalResearch.com: What should clinicians and patients take away from your report?

Dr. Ishimura:  Clinicians and patients have to know that eGFR in diabetic patients is inaccurate without correction by hemoglobin A1C or glycated albumin. They should  use eGFR corrected by hemoglobin A1C in future clinical practice, in order to know true accurate GFR.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Dr. Ishimura: We have created the new formulae of eGFR corrected by hemoglobin A1C or glycated albumin in 80 Japanese patients.  Further studies are needed to validate the formulae in other population in other countries, utilizing large number of patients.  However, we are sure that our formulae of eGFR corrected by hemoglobin A1C or glycated albumin are accurate and clinically useful.

Citation:

Poor Glycemic Control Is a Major Factor in the Overestimation of Glomerular Filtration Rate in Diabetic Patients

Diabetes Care. 2014 Mar;37(3):596-603. doi: 10.2337/dc13-1899. Epub 2013 Oct 15.

Tsuda A1, Ishimura E, Ohno Y, Ichii M, Nakatani S, Machida Y, Mori K, Uchida J, Fukumoto S, Emoto M, Nakatani T, Inaba M.