Published in:
Open Access 01-05-2011 | Article
Low transition rate from normo- and low microalbuminuria to proteinuria in Japanese type 2 diabetic individuals: the Japan Diabetes Complications Study (JDCS)
Published in: Diabetologia | Issue 5/2011
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Aims/hypothesis
The aim of the study was to determine the transition rate and factors associated with the progression of normo- and low microalbuminuria to diabetic nephropathy (overt proteinuria).
Methods
For 8 years we prospectively observed 1,558 Japanese patients with type 2 diabetes mellitus whose basal urinary albumin:creatinine ratio (UACR) had been measured as <17.0 mg/mmol at entry. The incidence of nephropathy (UACR >33.9 mg/mmol) was determined by measuring UACR twice a year.
Results
Progression to nephropathy occurred in 74 patients. The annual transition rate was 0.67%, and was substantially higher for the low-microalbuminuric group than for the normoalbuminuric group (1.85% and 0.23%, respectively; hazard ratio for the low-microalbuminuric group 8.45, p < 0.01). The hazard ratio for an HbA1c of 7–9% or ≥9% was 2.72 (p < 0.01) or 5.81 (p < 0.01) relative to HbA1c <7.0%, respectively. In comparison with individuals with a systolic blood pressure (SBP) of <120 mmHg, the hazard ratios for patients with an SBP of 120–140 mmHg or ≥140 mmHg were 2.31 (p = 0.06) and 3.54 (p < 0.01), respectively. Smoking also affected progression to proteinuria (hazard ratio 1.99, p < 0.01). In contrast, 30.3% of the low-microalbuminuric group returned to normoalbuminuria (i.e. were in remission).
Conclusions/interpretation
These results suggest that if patients with type 2 diabetes mellitus are receiving treatment from diabetologists for hyperglycaemia and hypertension when they are in the early stages of nephropathy (i.e. normo- or low microalbuminuria), their rate of transition to proteinuria is considerably lowered, and that differentiating patients with low microalbuminuria from those with high microalbuminuria might be clinically useful.
Trial registration
UMIN Clinical Trials Registry C000000222
Funding
The study was funded by the Ministry of Health, Labour and Welfare, Japan.