A cross-sectional survey of chronic kidney disease and diabetic kidney disease in Japanese type 2 diabetic patients at four urban diabetes clinics.

OBJECTIVE: Management of chronic kidney disease (CKD) is a critical issue in public health in attempt to prevent kidney failure and dialysis dependency. Since 1998, diabetes mellitus has been the leading cause of dialysis dependency in Japan. Previous reports demonstrated that the prevalence of CKD in diabetic patients was high; however albuminuria was not always present. This cross-sectional survey was performed 1) to indicate the prevalence of CKD and co-morbid illness in diabetic patients seen at diabetic clinics, and 2) to demonstrate the relationship between estimated glomerular filtration rate (eGFR) and urine albumin to creatinine ratio (ACR).

PATIENTS AND METHODS: A total of 288 consecutive adult type 2 diabetic patients seen at four diabetic clinics in the Tokyo Metropolitan Area were enrolled in November 2007. We excluded patients with kidney failure. Estimated GFR was calculated by the MDRD Study equation with the Japanese coefficient.

RESULTS: Patients had a mean age (+/- SD), 61 (+/- 12); male, 58%; mean BMI, 25.2 kg/m(2) (+/- 5.2); and mean HbA(1c), 7.1% (+/- 1.3). The prevalence of CKD stage 3 was 38% (109/288) with 64% (70/109) of them being normoalbuminuric. Co-morbid illnesses, including hypertension (p<0.001) and old stroke (p=0.02), were significantly higher in CKD stage 3 patients.

CONCLUSION: Our patients were relatively young and obese, reflecting urban clinical settings. The prevalence of CKD stage 3 patients was high. Clinicians need to check both eGFR and ACR to avoid underdiagnosis of CKD and diabetic kidney disease.