Mortality and hospitalizations are the accepted benchmarks used to measure the efficacy of heart failure treatments, but another factor — health literacy — appears to play a key role in outcome.
In a systematic review of 15 heart failure studies that included evolution of health literacy, inadequate health literacy was “statistically associated with mortality (RR: 1.41;95% CI: 1.06-1.88) and hospitalizations (RR: 1.12; 95% CI: 1.01-1.25),” wrote Matteo Fabbri, MD, of the department of health sciences research at the Mayo Clinic in Rochester, Minnesota, and colleagues in JACC Heart Failure.
The researchers searched Embase, MEDLINE, PsycINFO, and EBSCO CINAHI databases to identify studies that “evaluated health literacy among patients with HF and assessed mortality, hospitalizations, and ED visits for all causes with no exclusion by time, geography, or language.” From a list of 1,585 studies that met their baseline criteria, they selected 87 for full-text review, which yielded 15 studies that were included in the systematic review — 11 observational studies and four interventional studies.
They conducted a quantitative meta-analysis of findings from 10 of the 11 and the four interventional studies, adjusting “results for the main demographic (age, sex, education) and clinical confounders, including comorbidities …,” they wrote.
Looking just at mortality and inadequate health literacy in the observational studies, they identified five studies that had a combined enrollment of 6,491 heart failure patients, including 20% with inadequate health literacy. “Mortality was strongly associated with inadequate health literacy.” they found. “In particular, we first combined unadjusted RRs for each study, finding a 67% increased risk of mortality… When we considered the adjusted RRs from each individual study, the association with mortality decreased, although it remained statistically significant (RR: 1.41; 95% CI: 1.06-1.87; I2 = 77%).”
Of interest, one of the studies included in the mortality analysis was conducted outside of the United States. In that study, which was conducted in Spain, there was no association between health literacy and mortality. “This could reflect 2 factors: the cohort of patients with HF was much older than those of other studies, and the study was conducted in Spain, in an inherently different care delivery system, underscoring the need for further studies to be conducted outside the United States. Mortality had high statistical heterogeneity, possibly due to the different populations of the study,” they wrote.
In their analysis of hospitalizations, they found close to a 20% unadjusted increased risk for hospitalizations among heart failure patients with inadequate health literacy, and when the results were adjusted, the increased risk was lower but “remained statistically significant.”
They also looked at emergency department visits, but only four studies had data on this metric and they found no statistically significant associations.
The four interventional studies all included interventions aimed at improving patients’ health literacy, and in two of those four studies, health outcomes were improved.
Fabbri and colleagues suggested a number of possible explanations, or mechanisms, to explain why health literacy affects outcomes, including an obvious one: persons with inadequate health literacy may have less access to health care services, and when they do access such services, they may have less opportunity to “engage in effective physician/patient communication. This could be due to several reasons. For example, patients with inadequate health literacy might be less likely to seek clarifications, possibly because of feelings of shame of their literacy status.”
The authors argued that, given the “staggering mortality and hospitalization burden of heart failure,” their findings have important clinical implications and point to the need for evaluation of health literacy in this patient population.
Among the limitations noted by Fabbri et al was the inability to “statistically evaluate publication bias because of the limited number of studies for each outcome.” Moreover, the studies included evaluated health literacy using a variety of tools rather than a standard measurement. “Finally, it was not always clear if the assessment of health literacy took place in the outpatient or inpatient setting, which may have influenced the measurement,” they wrote.
Nonetheless, the authors noted that the study is “the first systematic review to quantify the magnitude of the association between inadequate health literacy and hospitalizations and ED visits. Moreover, we were able to combine the adjusted results, giving a more accurate measure of these associations… These findings have important clinical and public health implications and support the deployment of interventions to improve health literacy to improve outcomes among patients living with HF.”
Be aware that an inadequate level of health literacy is associated with higher risk for mortality and hospitalizations in patients with heart failure.
Screening for inadequate health literacy and developing interventions to improve health literacy may improve outcomes for patients living with heart failure.
Peggy Peck, Editor-in-Chief, BreakingMED™
The study was funded by the National Center for Advancing Translational Sciences, a component of the National Institutes of Health (NIH), and the National Heart, Lung and Blood Institute.
Fabbri had no disclosures.
Cat ID: 3
Topic ID: 74,3,730,3,6,192,925