Increased angiotensin-converting enzyme activities in diabetes mellitus: analysis of diabetes type, state of metabolic control and occurrence of diabetic vascular disease.

Serum angiotensin-converting enzyme activities were measured in 41 type 1 diabetics (16.4 +/- 4.0 U/ml), in 40 type 2 diabetics (15.0 +/- 5.2 U/ml) and in 52 controls (13.0 +/- 2.7 U/ml, mean +/- SD). Twenty six (32%) of 81 patients presented with serum angiotensin-converting enzyme activities above the normal range. No relation between serum angiotensin-converting enzyme activities and the presence or lack of diabetic vascular diseases in type 1 and type 2 diabetics could be detected. No significant differences in serum angiotensin-converting enzyme activities were found when comparing various types of diabetic vascular disease (retinopathy, neuropathy, renal failure, arterial vascular disease, diabetic vascular disease, coronary artery disease). However, mean serum angiotensin-converting enzyme activities were significantly increased in diabetics with retinopathy when compared with controls (p less than 0.0005). Correlation between metabolic long term control as determined by measuring glycohaemoglobin (HbA1) concentrations and serum angiotensin-converting enzyme activities could not be established. Serum angiotensin-converting enzyme activities did not show any correlations with duration of diabetes, age or sex of patients. A representative number of diabetics (32%) showed elevated serum angiotensin-converting enzyme activities, but a correlation with diabetic vascular disease, metabolic control or type of disease could not be established.