The relationship between carotid disease and retinopathy in diabetes: a systematic review

Abstract

Background: Since studies of the relationship between carotid disease and diabetic retinopathy (DR) have shown apparent inconsistencies, the aim of this study was to conduct a systematic review of available published data. Methods: Electronic databases were searched independently by two reviewers, according to an iterative protocol, for relevant articles. The search term used was "diabetes AND (carotid disease OR intima-media OR carotid plaque OR carotid stenosis OR carotid arterial disease OR carotid artery disease OR carotid atherosclerosis) AND (retinopathy OR diabetic retinopathy)". Results: From 477 publications, 14 studies were included. There were differences in the variables used as markers of carotid disease and DR across the included studies. Ten studies used carotid disease as the dependent variable, and the remainder used DR. All but one study involved cross-sectional data. Most studies reported a statistically significant association between at least one parameter of carotid disease as assessed by ultrasound and DR presence or severity. Only four studies reported no significant association. A common limitation was the use of convenience participant sampling. Conclusions: There appears to be an increased likelihood of DR when there is ultrasonographic evidence of carotid disease, and vice versa. The available studies suggest that there may be a direct relationship between DR and carotid macrovascular disease and/or that these complications co-exist due to shared risk factors. If carotid disease is detected, retinal assessment should be performed. If DR is identified, intensive cardiovascular disease risk management should be considered. Additional longitudinal studies are needed to assess the directionality of the association.

Retinal dysfunction induced in a mouse model of unilateral common carotid artery occlusion

“…In human, CCAO or CCAS is a devastating cause of ocular ischemic syndrome ( Faries et al, 2006 ). Ocular ischemia resulting from CCAO or CCAS has gradually received attention in that several ocular disorders, such as ischemic optic neuropathy, diabetic retinopathy and glaucoma, are suggested to be involved with cardiovascular diseases-associated retinal ischemic states ( Chou et al, 2018 ; Drinkwater, Davis & Davis, 2020 ; Harris et al, 1999 ; Osborne et al, 2004 ). Therefore, CCAO or CCAS has been attempted to develop animal models for such retinal ischemic diseases.…”

The association between carotid disease, arterial stiffness and diabetic retinopathy in type 2 diabetes: the Fremantle Diabetes Study Phase II

“…A community‐based study which excluded people with prior cardiovascular disease showed that any diabetic retinopathy was associated with CCA IMT >1 mm (OR 1.84) and the presence of carotid plaque 19 . Other clinic‐ and hospital‐based studies have found a similar positive association with IMT, 10,13 no association with IMT but positive associations with other measures of carotid disease, 20–22 and no association with any measure of carotid disease 5,23 …”

“…The results of studies assessing the association between diabetic retinopathy and carotid disease have been inconsistent 5 . This could reflect differences in participant sources, selection criteria, techniques of vascular assessment, and/or the availability of explanatory and confounding variables.…”

Featureless retina in diabetic retinopathy: Clinical and fluorescein angiographic profile

“…[ 22 ] However, the literature is equivocal about the exact nature of carotid vascular parameters associated with the presence or severity of DR as most of the studies have been cross-sectional. [ 23 ] We performed Doppler imaging of the internal carotid artery only in the cases with angiographic features of ocular ischemic syndrome, which was an exclusion criterion ( supra vide ), and therefore could not correlate this parameter with asymmetric DR in this series. These shortcomings need to be addressed by a larger, longitudinal study of FLR with noninvasive wide-angle diagnostic imaging and a more detailed systemic assessment to assess its natural course and long-term prognosis.…”