Diabetics with normal coronary arteries: Clinical features and prognosis

Background: Diabetic patients comprise a large proportion of patients referred for coronary angiography. Only a minority of these patients will be found to have normal coronary arteries. Aim: To characterize diabetic patients who have angiographically normal coronary arteries. Methods: Case-control study based on a computerized database. Results: Using our computerized database, 13,342 consecutive patients referred for coronary angiography were identified. Diabetes mellitus was diagnosed in 24% of cases. Angiographically normal coronary arteries were found in 151 (5%) and 1228 (12%) of diabetic and non-diabetic patients, respectively (p<0.01). Diabetic patients with angiographically normal coronary arteries were matched with 155 diabetic patients who were catheterized on the same day but were found to have coronary artery disease. The median follow-up period was 1,774 days. The age of the diabetic patients with normal coronary arteries and diabetic patients with coronary artery disease was 5710 and 6410 years old respectively (p<0.01). A total of 39% and 60% of diabetic patients with normal coronary arteries and with coronary artery disease respectively were males, (p<0.01). Dyslipidemia was diagnosed in 66 (43%) of the diabetic patients with normal coronary arteries and 87 (57%) of the diabetic patients with coronary artery disease (P<0.01). After controlling for age and sex, the finding of normal coronary arteries was associated with decreased mortality (OR: 0.47, 95% CI 0.23 to 0.95). Conclusions: In diabetic patients referred for angiography it is unusual to find angiogrtaphically normal arteries. These patients have a relatively benign prognosis, as opposed to diabetic patients with evident coronary disease.