UCLA

Background:

The morbidity, mortality and costs associated with hypertension and heart failure in the US are enormous. In the US population, the positive role of having a usual source of care (USOC) on the receipt of preventative services is known. However, associations between USOC and hypertension control and whether a differential association across age groups exists is unknown in the US population.

Heart failure affects patients in myriad ways: economically, physically, socially and emotionally. Heart failure negatively impacts health-related quality of life (HRQOL), but age-related differences in HRQOL (and specifically emotional health) are unknown. Finally, studies are mixed on whether increased monitoring and nurse coaching can impact emotional health post-discharge in recently hospitalized heart failure patients.

Methods:

To assess the relationship between USOC and hypertension control, I use data from the National Health and Nutrition Examination Survey (NHANES) from 2007-2012. I utilize multivariable logistic regression to evaluate the association between having a USOC and hypertension control. The differential effect of USOC on hypertension control by age is assessed using predicted marginal effects for various age groups within this model and then analyzing pairwise comparisons of the marginal effects.

To examine age-related differences in emotional health in recently hospitalized heart failure patients, I analyze longitudinal data from the BEAT-HF study—a multicenter trial comparing the impact of wireless remote monitoring and nurse coaching versus usual care on emotional health for patients hospitalized with heart failure. Multivariable linear regression and mixed effects models are utilized to evaluate whether there are baseline and longitudinal differences in emotional health across age groups. To analyze whether the association between age and emotional health outcomes is mediated by physical health and/or social health I use a multi-step regression model allowing for cross-equation error correlation (“seemingly unrelated regression”) and structural equation modeling. To assess the intervention effect on emotional health in the study, I utilize mixed effects linear regression controlling for treatment arm and hospital level random effects.

Results:

In adjusted analyses, those with a USOC had a higher odds of hypertension control [OR=3.89, 95%CI (2.15-6.98)]. The marginal effect of having a USOC is associated with a 30 percentage-point higher probability of controlled blood pressure compared to those without a USOC [marginal difference in probability=0.30, 95%CI (0.19-0.41)]. In tests of pairwise comparisons of marginal effects, there was a 7-8 percentage point difference in marginal effect of USOC on hypertension control in the youngest group (compared to all middle age groups) which was statistically significantly lower. In terms of the US population this difference amounts to 70,000-80,000 fewer young individuals with controlled hypertension per million individuals with hypertension. There was also a 3-4 percentage point difference in marginal effect in the oldest age group (compared to all middle age groups) which was statistically significantly lower. This difference amounts to 30,000-40,000 fewer older individuals with controlled hypertension per million in the US hypertension population.

In the BEAT-HF trial, older individuals had better emotional health in multivariable linear regression models controlling for demographic and clinical characteristics [lower scores indicating better emotional health; β=-1.9, 95% CI (-3, -0.8)]. The effect of age on emotional health was partially mediated by physical health in all models (Barron and Kenney multi-step regression, seemingly unrelated regression with simultaneous regression equations and correlated error terms, and structural equation modeling). The mixed effects analysis for the intervention’s effect on emotional health showed a small but statistically significant effect at 180 days [=-1.3, 95%CI(-2.2, -0.02)]. By Cohen’s rules of thumb the standardized difference in groups approaches a “small” effect size (adjusted effect size(ES)=0.17 vs. “small” ES=0.2), but is below it. In mixed effects models using tests of interaction, there was no differential effect of treatment by age or social isolation.

Conclusion:

Having a usual source of care is significantly associated with improved hypertension control in the US population. The variation in the association across age groups has important implications in targeting age-specific anti-hypertensive strategies to reduce the burden of hypertension in the US population.

Older patients with heart failure in this study have better emotional health than younger patients. This may be related to increased coping or acceptance of limitations, since older patients overall had more comorbidities and a higher proportion of NYHA class III heart failure. Both treatment and control groups had improved emotional health scores in the post-discharge period, but the telemonitoring and nurse coaching intervention had small positive effects on emotional health at 180 days. Treatment non-adherence may have minimized the effect on emotional health, but this large-scale randomized controlled trial likely gives an accurate assessment of the real-world effect of telemonitoring and nurse coaching on a broad heart failure population.