Income disparity and incident cardiovascular disease in older Americans

To examine the association between income and cardiovascular disease (CVD) in community-dwelling older adults.

Of the 5795 Medicare-eligible community-dwelling older Americans aged 65-100 years in the Cardiovascular Health Study (CHS), 4518 (78%) were free of baseline CVD, defined as heart failure, acute myocardial infarction, stroke, or peripheral arterial disease. Of them, 1846 (41%) had lower income, defined as a total annual household income <$16,000. Using propensity scores for lower income, estimated for each of the 4518 participants, we assembled a matched cohort of 1078 pairs balanced on 42 baseline characteristics. Outcomes included centrally adjudicated incident CVD and mortality.

Matched participants (n = 2156) had a mean age of 73 years, 63% were women, and 13% African American. During an overall follow-up of 23 years, incident CVD, all-cause mortality and the combined endpoint of incident CVD or mortality occurred in 1094 (51%), 1726 (80%) and 1867 (87%) individuals, respectively. Compared with the higher income group, hazard ratio (HR) for time to the first occurrence of incident CVD in the lower income group was 1.16 with a 95% confidence interval (CI) of 1.03 to 1.31. A lower income was also associated with a significantly higher risk of all-cause mortality (HR, 1.19; 95% CI, 1.08-1.30), and consequently a higher risk of the combined endpoint of incident CVD or death (HR, 1.20; 95% CI, 1.09-1.31).

Among community-dwelling older Americans free of baseline CVD, an annual household income <$16,000 is independently associated with significantly higher risks of new-onset CVD and death.