Low health literacy linked to high mortality in HF patients
MedWire News: Study findings show that the less able patients with heart failure (HF) are to understand basic health information, the higher their risk for all-cause mortality.
A group of researchers led by Pamela Peterson (Denver Health Medical Center, USA) conducted a retrospective cohort study of outpatients with HF to investigate the association between health literacy, all-cause mortality, and all-cause hospitalization.
The study, published in JAMA, included 1494 HF patients who were identified between January 2001 and May 2008, and underwent follow-up for a median of 1.2 years. Their health literacy was assessed using a survey which comprised 3 screening questions scored on a 5-point summed health literacy scale. The outcomes of interest were all-cause mortality, measured by comparing Kaiser Permanente of Colorado (KPCO) databases and death certificates, and all-cause hospitalization, identified using claims data.
Of the 1494 participants, 17.5% obtained a score greater than 10, indicating low health literacy. These patients were older, more likely to be of low socioeconomic status and to have co-existing illnesses such as diabetes, hypertension, and stroke, and less likely to have a high-school education than patients with adequate health literacy. Adequate health literacy was indicated by a summed total score of 10 or lower.
During follow-up 124 patients died, 17.6% of whom were from the low health literacy group. Kaplan-Meir analysis showed that the unadjusted rate of mortality was higher among the low health literacy group than the adequate literacy group (unadjusted hazard ratio [HR]=2.96). There were also 366 hospitalizations, with 30.5% from the low health literacy group. The unadjusted rate of hospitalization was also found to be higher in this group (HR=1.45).
Peterson et al found that after adjusting for demographic variables, socioeconomic status, education, comorbid conditions, year of cohort entry, and left ventricular ejection fraction, low health literacy was independently associated with an increased risk for mortality (17.6% vs 6.3%, HR=1.97,) but was not associated with all-cause hospitalization (30.5% vs 23.2%, HR=1.05).
Using stratified analyses, the team found that low health literacy was not significantly associated with hospitalization among those patients living independently (29.8% vs 19.5%, HR=1.33 [95% confidence interval: 0.98-1.80]), but was associated with a lower risk for hospitalization among those patients living in nursing facilities or receiving hospice care (33.3% vs 57.4%, HR=0.57; p=0.006 for interaction).
"This finding supports efforts to determine whether interventions to screen for and address low health literacy can improve health outcomes in patients with heart failure," the researchers conclude.
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By Piriya Mahendra