The impact of metabolic and blood pressure control on incidence and progression of nephropathy. A 10-year study of 385 type 2 diabetic patients.

The aim of the present study was to find clinical parameters affecting incidence and progression of nephropathy in type 2 diabetic patients. A prospective study for 10 years was performed in 385 type 2 diabetic patients (diabetes diagnosis > or =30 years) attending a hospital-based outpatient clinic. Medical risk indicators like diabetes duration, HbA(1c), and blood pressure were related to the development and progression of diabetic nephropathy. The 10-year incidence of microalbuminuria was 38% (n=95) and that of macroalbuminuria was 10% (n=26). Out of 103 patients with microalbuminuria, 38 developed macroalbuminuria. In 252 normoalbuminuric patients, the mean of the HbA(1c) (P<.05) levels obtained during the study were associated with a doubling of the fractional albumin clearance. In contrast, blood pressure levels, age, diabetes duration, type of diabetes treatment, BMI, and gender were not (Cox regression analysis). Among 133 patients with micro- or macroalbuminuria, 22 more than doubled their serum creatinine level, in contrast to only 6 of 252 patients without. With Cox regression analysis, systolic (P<.01), but not diastolic, blood pressure or HbA(1c) levels or the above mentioned risk factors were associated with a doubling in serum creatinine. A total of 19 patients developed uremia during the study, out of whom 6 were in need of dialysis and 1 has had a renal transplantation, and 14 (74%) died. HbA(1c) (P<.05) and systolic blood pressure (P<.001) levels were associated with development of uremia, but not diastolic blood pressure or the other parameters mentioned above. This study shows that poor metabolic control is associated with development and high blood pressure with progression of nephropathy in type 2 diabetic patients.