Severity of coronary artery disease and retinal microvascular signs in patients with diagnosed versus undiagnosed diabetes: cross-sectional study.

Background: There is increasing evidence that a considerable proportion of patients with diabetes remain undiagnosed and untreated, however, it is unclear whether this is associated with more severe coronary artery disease (CAD) and microvasculature changes compared with diagnosed patients. We assessed CAD extent and severity, along with changes to the retinal microvascular structure in participants with undiagnosed versus diagnosed type 2 diabetes.

Methods: Participants of the Australian Heart Eye Study were stratified into participants with previously diagnosed diabetes (n=489), undiagnosed diabetes (n=76) and no diabetes (n=1,112). Retinal vessel caliber was measured from digital retinal images. Extent and severity of CAD was assessed using Extent and Gensini scores from angiography findings, respectively.

Results: Participants with undiagnosed and diagnosed diabetes versus those with no diabetes (reference group) had increased odds of being in the highest quartile of Gensini scores, multivariate adjusted odds ratios (OR) =7.02 [95% confidence interval (CI), 2.04-24.1] and OR =2.76 (95% CI, 1.67-4.55), respectively. Participants with undiagnosed and diagnosed diabetes versus those with no diabetes also had increased odds of being in the highest quartile of Extent scores, multivariate adjusted OR =7.63 (95% CI, 2.15-27.10) and OR =3.72 (95% CI, 2.22-6.27), respectively. No significant differences were observed in retinal vessel caliber between participants with undiagnosed versus diagnosed diabetes.

Conclusions: The present study demonstrated that participants with undiagnosed diabetes compared to those with previously diagnosed diabetes, had a stronger likelihood of having more severe and extensive CAD. However, retinal microvascular signs did not differ by diabetes status.