Albumin excretion rate and its relation to kidney disease in non-insulin-dependent diabetes mellitus.

OBJECTIVE

To estimate the occurrence of increased albumin excretion rate (AER) and its significance as a marker of diabetic kidney disease in non-insulin-dependent diabetic subjects.

DESIGN

Population-based, controlled cross-sectional study.

SETTING

A primary health care centre in the city of Tampere, south-west Finland.

SUBJECTS

Consecutive, recently diagnosed (n = 150) and long-term (n = 146) middle-aged non-insulin-dependent diabetic subjects. Matched non-diabetic control subjects (n = 150).

MAIN OUTCOME MEASURES

Albumin excretion rate, fractional AER, microalbuminuria (AER 30-300 mg 24 h-1), clinical nephropathy (AER exceeding 300 mg 24 h-1) and kidney biopsy in diabetic subjects with an AER exceeding 100 mg 24 h-1.

RESULTS

Mean (+/- standard deviation [SD]) 24-h AER was increased in recently diagnosed diabetic subjects, 54 (111) mg, and long-term diabetic subjects, 134 (479) mg, compared to non-diabetic control subjects, 16 (19) mg. The fractional AER was 7.5 (18.3) x 10(-6) in recent diabetic subjects, 53.1 (306.9) x 10(-6) in long-term diabetic subjects and 2.8 (3.7) x 10(-6) in non-diabetic control subjects. Microalbuminuria was found in 8% of non-diabetic subjects, in 29% of recent and in 27% of long-term diabetic subjects. The prevalence of clinical nephropathy was 7% in long-term and 4% in recent diabetic subjects, whilst no non-diabetic subject had nephropathy. In 12 of 16 eligible kidney biopsies, diabetic glomerulosclerosis was found, in four subjects the finding was normal.

CONCLUSIONS

The AER is clearly increased in recent non-insulin-dependent diabetic subjects and further increased in diabetic subjects with a mean disease duration of 10 years. An increased AER in non-insulin-dependent diabetic subjects suggests diabetic kidney disease.