Noninvasive CAD Screening May Reduce Cardiac Events in Individuals With Asymptomatic Diabetes

Noninvasive coronary artery disease (CAD) screening in individuals with asymptomatic diabetes may reduce cardiac events such as nonfatal myocardial infarctions (MIs) and heart failure (HF) hospitalizations, according to a study published in the European Heart Journal of Cardiovascular Imaging.

Researchers conducted a systematic review of the literature and meta-analysis of randomized controlled trials (RCT) to determine whether noninvasive screening for CAD would improve cardiac outcomes in asymptomatic individuals with diabetes.

Two investigators identified a total of 5 RCTs with a globally low risk for study bias, containing 3299 individuals who were randomly assigned to 1 of 2 groups: a screening group (n=1652) or a control group (n=1647). The number of cardiac events experienced on follow-up in these individuals totaled 189 (5.7%) at an average of 4.1 years.

Results showed that all combined cardiac events were significantly reduced by 27% in individuals who were noninvasively screened for CAD (relative risk [RR], 0.73; 95% CI, 0.55-0.97; P =.028; I²=36%; number needed to screen, 56); however, there was no observed reduction in cardiac death as a result of screening (RR, 0.92; 95% CI, 0.53-1.60; P =.77; I²=39%). Despite being the driving force behind this observed reduction, when observed individually, the decreases noted in nonfatal MIs and HF were nonsignificant.

Analyses of medication use showed no significant effect of screening; however, there was an increase use of statins in individuals who underwent noninvasive CAD screening (RR, 1.05; 95% CI, 0.99-1.10; P =.092; I²=31%).

When 2 non-RCTs were included in the analysis with the 5 RCTs, a stronger reduction of 42% in overall cardiac events was observed (RR, 0.58; 95% CI, 0.37-0.91; P =.017; I²=66%; number needed to screen, 35), which was driven by a now statistically significant reduction in nonfatal MIs (RR, 0.52; 95% CI, 0.32-0.84; P =.008, I²=31%).

Researchers concluded that despite demonstrating an overall significant reduction in cardiac events with noninvasive screening, the study results are not strong enough to recommend the standardization of noninvasive CAD screening in individuals with asymptomatic diabetes, as the significance of the findings fell short when cardiac events were assessed separately in each individual trial, and overall mortality was not significantly affected. These findings could potentially be explained by a type II statistical error as a result of undersampling in the individual studies, and justify the need for larger scale studies.

Reference

Clerc OF, Fuchs TA, Stehli J, et al. Non-invasive screening for coronary artery disease in asymptomatic diabetic patients: a systematic review and meta-analysis of randomised controlled trials [published online February 14, 2018]. Eur Heart J Cardiovasc Imaging. doi: 10.1093/ehjci/jey014