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Retinal Microvascular Signs and Disability in the Cardiovascular Health Study

DH Kim, PHM Chaves, AB Newman... - Archives of ..., 2011 - Am Med Assoc Objective To study the associations of retinal microvascular changes, which are associated with systemic conditions and cognitive decline, with disability in performing activities of daily living (ADL). Design Prospective cohort study of 1487 community-dwelling participants in ...

The strengths of this study are the prospective follow-up (up to 7.8 years); standardized assessments; and consistent findings from several post hoc analyses under different assumptions. A limitation of this study is selection bias, because participants who did not have gradable retinal photographs were more likely than those who did to be older, female, and black and to have more vascular risk factors and diseases.20 If sicker individuals who did not have retinal photography were more likely to have retinal signs and to develop ADL disability during the follow-up, a selection bias could occur and underestimate the association between retinal signs and ADL disability. In CHS, retinal photography, carotid ultrasonography, and brain MRI were taken near the end of in-person follow-up assessment in 1997-1999. Thus, we used prevalent measures of executive function, gait speed, and depressive mood instead of incident measures. This is an important limitation in interpreting our mediation analysis. In addition, residual confounding cannot be excluded, despite our efforts to adjust for potential confounders that were selected based on biological plausibility. For instance, ankle-arm index, which may be associated with both retinal signs and ADL disability, was not measured at baseline for this analysis. In addition, decreased vision could explain some of the association between retinal signs and disability. Finally, low prevalence of individual retinal signs resulted in 95% C Is that were too wide to exclude a modest association. Despite limited power, we found a significant association of high burden of retinal signs with disability. A larger study with more events is needed to evaluate the effects of individual retinal signs, which will further strengthen our study.