Frailty, visual impairment, and risk of cardiovascular disease mortality: The 1997-2000 National Health Interview Survey

Background: Visual impairment (VI) has been associated with an increased risk of cardiovascular disease (CVD) mortality in adults. However, it is not clear if this association is a marker for frailty.

Method: The National Death Index linkage through 2002 with participants of the 1997-2000 National Health Interview Survey was performed (2,300 CVD deaths among 121,481 participants). A frailty indicator was created by summing responses to 12 questions measuring physical functioning and activities of daily living (range=0-48). Two questions were used to classify VI status: “Do you have any trouble seeing, even when wearing glasses or contact lenses?” and “Are you blind or unable to see at all?” Multivariable Cox regression models included age, gender, race/ethnicity, education, smoking status, alcohol use, VI, and frailty status.

Results: The prevalence of participants reporting no VI, some VI, and severe VI were 89.8%, 9.7%, and 0.5%, respectively. In the multivariable hazard model those with mild (1-13) and moderate/severe frailty (14-48) scores at baseline were at significantly increased risk of CVD death relative to those reporting no difficulties: hazard ratio (HR)=1.95; [95% confidence interval=1.68-2.26] and HR=4.78 [4.11-5.56], respectively. Both mild/moderate and severe visual impairment remained associated with a significantly increased risk of CVD death (HR=1.22 [1.08-1.37] and HR=1.62 [1.22-2.16], respectively). There were no interactions between VI and frailty.

Conclusion: Control for baseline frailty levels reduced, but did not eliminate the association between VI and CVD mortality. Interventions designed to reduce frailty and/or VI may also lower CVD mortality risk in community-residing adults.