Patients with uncontrolled type 2 diabetes (T2D), specifically those with inadequate glycaemic control, may have a higher incidence of myocardial ischaemia and risk of coronary artery disease (CAD), according to a study presented at SPCRS 2017.

“CAD is the leading cause of mortality among patients with T2D. Patients with this disease usually have myocardial ischaemia that are silent and in advanced stage when symptoms manifest,” said lead author Dr Henry Canizares from the Division of Nuclear Medicine at the Philippine Heart Center in Quezon City, Philippines.

The researchers retrospectively analysed 206 patients with T2D (75 percent male), but no history of any cardiac events, who underwent myocardial perfusion scintigraphy (MPS) using thallium-201 or technetium-99m sestamibi within 18 months. Participants were divided into two groups: adequate (n=114, mean age 58.2 years, HbA_1c <7.0 percent) and inadequate glycaemic control (n=92, mean age 60.2 years, HbA_1c ≥7.0 percent). [SPCRS 2017, abstract D-69]

Compared with patients who had an HbA_1c level of <7.0 percent, patients with an HbA_1c level of ≥7.0 percent had a significantly higher incidence of mild and moderate to severe myocardial ischaemia (16.30 percent vs 9.65 percent and 36.96 percent vs 11.40 percent, respectively).

Individuals with myocardial ischaemia who had an HbA_1c level of ≥7.0 percent had a higher risk of CAD compared with those with HbA_1c <7.0 percent (67.1 percent vs 32.9 percent, odds ratio [OR], 4.27, 95 percent confidence interval [CI], 2.32–7.85).

Moreover, patients with an HbA_1c level of ≥7.0 percent for more than 10 years had a further increased risk of CAD than those with an HbA_1c level of <7.0 percent (OR, 7.26, 95 percent CI, 2.10–25).

“Inadequate glycaemic control and its duration equates to more MPS defects,” Canizares noted.

In addition, a direct positive weak association to abnormal MPS results (r=0.3279; p<0.0001) was noted in patients with an HbA_1c level of ≥7.0 percent, which means that with higher HbA_1c levels, the more MPS defects will be observed, said Canizares.

The findings were consistent with a previous study showing that higher abnormal MPS and risk of CAD were observed in patients with T2D who had a long-term inadequate glycaemic control. [Clin Cardiol 2012;35:565-569] 

“The result of this study suggests early aggressive glycaemic control and possible incorporation of stress MPS in clinical practice guidelines in screening for CAD among this population. Stress MPS can be very helpful in early detection and prevention of complication for CAD through a noninvasive method,” said Canizares.