OBJECTIVES: Age and comorbidities are independent risk factors for mortality in adults with heart failure (HF). This study explored the modifying effect of age on the association between comorbidities and all-cause mortality among a national sample of adults with HF.

METHODS: This was a retrospective cohort study based on public-use data of the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2010, on adults who self-reported as having been diagnosed with HF. The outcome of the study was all-cause mortality. The primary independent variable was type of comorbidity (non-cardiovascular, cardiovascular and mixed). Descriptive statistics were used to describe the relationship between comorbidity and variables of interest. Age-stratified multivariate Cox Proportional Hazards models were used to assess the association of comorbidity with all-cause mortality overall and by age strata (≤60, 61–70,71–80, and >80 years old).

RESULTS:The study included 926 HF subjects: mean age was 68 years, and 42% died during follow-up. The age-specific all-cause mortality rates of subjects ≤60, 61 – 70, 71 – 80, and > 80 years of age, were 20%, 28%, 48% and 82% respectively. In the overall cohort, subjects with non-cardiovascular and mixed comorbidities had a higher risk of all-cause mortality than those with cardiovascular comorbidities (HR=2.0,95%CI=1.2-3.2 and HR=1.6, 95% CI=1.1-2.2 respectively). The risk of all-cause mortality for mixed comorbidities compared to cardiovascular comorbidities was higher for subjects 61-70 years of age (HR=5.4, 95% CI=1.4-19.7), but lower for subjects >80 years of age (HR=0.5,95%CI=0.4-0.8).

CONCLUSIONS: We found an association of higher risk of all-cause mortality with mixed and non-cardiovascular comorbidities compared to cardiovascular comorbidities in different age-groups. These findings may help to inform clinicians and health care providers on the management of HF patients with comorbidities and of different age groups.