Undiagnosed coronary artery disease in long-term type 1 diabetes. The Dialong study.

AIMS: We studied the total prevalence of obstructive coronary artery disease (CAD), undiagnosed CAD and absent CAD in persons with ≥45-year duration of type 1 diabetes (T1D) versus controls, and associations with mean HbA1c , LDL-cholesterol and blood pressure over 2-3 decades.

METHODS: We included 76% (n = 103) of all persons with T1D diagnosed ≤1970 attending a diabetes center and 63 controls without diabetes. We collected 20-30 years of HbA1c , LDL-cholesterol and blood pressure measurements. Participants without previously diagnosed coronary heart disease (CHD) underwent Computed Tomography Coronary Angiography (CTCA). Undiagnosed obstructive CAD was defined as any coronary stenosis >50% on CTCA, absent CAD as no detected plaque, and total obstructive CAD as either obstructive CAD on CTCA or previous CHD diagnosis.

RESULTS: The prevalence of undiagnosed, absent and obstructive CAD was 24% (21/88), 16% (14/88) and 35% (36/103) in T1D versus 10% (6/60), 50% (30/60) and 14% (9/63) in controls (all p < 0.05). Mean HbA1c was associated with undiagnosed obstructive CAD (OR 2.30 95% C.I. 1.13-4.69), while mean LDL-cholesterol was inversely associated with absent CAD (0.12, 0.04-0.43).

CONCLUSIONS: The prevalence of undiagnosed obstructive CAD was high (24%) in this cohort of long-term survivors with T1D. Mean LDL-cholesterol and HbA1c were associated with CAD.