Prevalence of diabetic nephropathy in primary care type 2 diabetic patients with hypertension: data from the Korean Epidemiology Study on Hypertension III (KEY III study)

Background. The prevalence of albuminuria is known to be higher in hypertensive compared to normotensive non-diabetic patients. In addition, systolic blood pressure (BP) is found to be an independent risk factor for albuminuria in type 2 diabetes mellitus (T2DM). Based on these findings, the prevalence of albuminuria is expected to be higher in T2DM with hypertension relative to T2DM without hypertension, but it has been largely unexplored. Methods. Prevalence rates of microalbuminuria, macroalbuminuria and renal insufficiency (RI) were investigated among 3738 hypertensive T2DM patients from 350 nationwide primary care clinics. Independent factors associated with albuminuria and RI were also characterized. Results. Clinical and laboratory data of 3712 patients were included in the analysis. BP was controlled in only 1164 patients (31.4%). There were 2595 normoalbuminuric patients (70.6%), and microalbuminuria and macroalbuminuria were present in 850 (23.1%) and 230 (6.3%), respectively. The prevalence of RI was 32.1% based on estimated glomerular filtration rate (eGFR) by Modification of Diet in Renal Disease formula. Systolic BP correlated significantly with the natural logarithmic values of urinary albumin-to-creatinine ratio (ACR) (R = 0.16, P < 0.0001). Multivariate logistic regression analysis revealed that male sex, the duration of diabetes, systolic BP, glycated hemoglobin and eGFR were significant independent factors associated with the presence of albuminuria, while advanced age, female sex, the duration of diabetes and urinary ACR were significant independent risk factors for RI. Conclusions. A significant proportion of T2DM patients with hypertension had albuminuria and RI, and the duration of diabetes mellitus rather than the duration of hypertension was a significant independent factor associated with albuminuria and RI.