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Undiagnosed CAD prevalence elevated in long-term type 1 diabetes

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February 7, 2019

LDL cholesterol and HbA1c levels in adults with type 1 diabetes may be associated with coronary artery disease, which is highly prevalent in older adults with type 1 diabetes, according to findings published in the Journal of Diabetes and its Complications.

“Persons with [type 1 diabetes] live much longer today, resulting in an ageing group of people with [type 1 diabetes]. There is a high prevalence of cardiovascular disease in long-term [type 1 diabetes]. However, the prevalence of undiagnosed CAD in this group is not known,” Kristine Bech Holte, MD, a research fellow in the department of endocrinology, morbid obesity and preventive medicine at Oslo University Hospital in Norway, and colleagues wrote. “The pathophysiology, age of diagnosis, lipid profile and the features of coronary atherosclerosis differ between [type 1 diabetes] and [type 2 diabetes]. Therefore, it is essential to study CAD in persons with [type 1 diabetes] rather than extrapolating data from studies on [type 2 diabetes], to guide clinical decision-making.”

Holte and colleagues recruited participants from the Dialong study, which included adults with type 1 diabetes who were diagnosed at the Norwegian Diabetics’ Centre in Oslo, Norway, before 1971 (n = 88; mean age, 61.5 years; mean BMI, 25.8 kg/m2; 53% women). The researchers also included a control group, which was mainly made up of spouses and friends of the participants (n = 60; mean age, 62.3 years; mean BMI, 25.5 kg/m2; 57% women). Data from the Dialong study included HbA1c values between 1980 and 2015 and LDL cholesterol values between 1983 and 2015.

All participants underwent CT coronary angiography to assess CAD status. The presence of a stenosis resulting in more than a 50% lumen reduction in one or more coronary arteries equated to undiagnosed obstructive CAD. If a participant had no plaque in the coronary arteries, they were considered to have absent CAD. Total obstructive CAD required previous coronary heart disease or obstructive CAD. Lastly, clinically significant CAD was characterized by a stenosis that required revascularization therapy, the researchers wrote.

Undiagnosed obstructive CAD was more prevalent in the diabetes group compared with the control group (24% vs. 10%; OR = 2.8; 95% CI, 1.06-7.5). Prevalence was also higher for total obstructive CAD in the diabetes group compared with the control group (35% vs. 14%; OR = 3.22; 95% CI, 1.43-7.27). Clinically significant CAD was identified in 12.5% of the diabetes group and 3% of the control group (OR = 4.1; 95% CI, 0.88-19.4). Conversely, 50% of participants in the control group exhibited absent CAD compared with 16% of the diabetes group (OR = 0.19; 95% CI, 0.09-0.41), according to the researchers.

Undiagnosed obstructive CAD was associated with mean HbA1c (OR = 2.3; 95% CI, 1.13-4.69), whereas an inverse relationship was discovered between mean LDL cholesterol and absent CAD (OR = 0.12; 95% CI, 0.036-0.43).

“Worse long-term control of LDL [cholesterol] was inversely associated with having absent CAD, and mean HbA1c was associated with undiagnosed obstructive CAD, confirming the importance of strict glucose and lipid control in [type 1 diabetes],” the researchers wrote. “The present study also adds to the argument of evaluating persons with long-term [type 1 diabetes] with poor lipid and glycemic control for obstructive CAD with CT [coronary angiography].” – by Phil Neuffer

Disclosures: The authors report no relevant financial disclosures.

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