Vaccinations in Decline at Heart Failure Hospitalizations at GWTG-HF Centers

August 09, 2018

The proportion of patients hospitalized with heart failure (HF) who received influenza and pneumococcal vaccinations fell off significantly between the 2012 and 2017 flu seasons at centers participating in an HF registry, with those who actually declined vaccination jumping by about a third.

Vaccination refusals made up almost one fourth of those eligible for vaccination.

Rates of vaccination varied by hospital and were highest at centers that also led the field on other HF-care quality measures.

The finding of "increasing refusal rates and stagnant to declining vaccination rates over the past five years is grounds for significant public health concern," write the authors, led by Ankeet S. Bhatt, MD, MBA, Duke University, Durham, North Carolina, in a report published August 8 in JACC: Heart Failure.

The analysis looked only at patients with HF who were eligible for vaccination and without contraindications at 392 hospitals participating in the Get With The Guidelines–Heart Failure (GWTG-HF) quality improvement program of the American Heart Association.

The increasing vaccination-refusal rates might be related to "some of the noise that comes out regarding vaccinations having certain risks," senior author Adrian F. Hernandez, MD, MHS, also from Duke University, said to theheart.org | Medscape Cardiology, referring to abundant but usually misguided news and social media reports claiming serious side effects or complications from vaccinations.

"But what people forget is that the benefit of influenza vaccination far outweighs the risk," he said. The health profession can help change that by "providing more education about the benefits-to-risks for vaccination."

Also, "each time there's an encounter with the health system, that's a chance to change care and improve health. Often in the past people have only thought about vaccination as an outpatient issue, but we certainly can be thinking about it across the spectrum of encounters from hospital to home," Hernandez said.

That one in four patients in the analysis declined vaccinations "to me is just shocking and concerning, given how much we know about the potential benefits of flu vaccination in this particular population, and how vulnerable these patients are, and that the guidelines recommend them," Jacob A. Udell, MD, MPH, said in an interview.

That vaccination rates are declining in patients with HF exacerbations "means that we're losing the battle, the message, for the hearts and minds of these patients, literally. And we have to do a better job," said Udell, from the University of Toronto, Ontario, Canada, who isn't connected with the current analysis.

Vaccination and Clinical Outcomes

Provocatively, and at odds with earlier observational studies, neither influenza nor pneumococcal vaccinations were associated with improved 1-year mortality or hospitalization rates in a subgroup of the total cohort with data linked to Medicare claims. 

But the authors and Udell downplayed the significance of those findings, emphasizing that the analysis was heavily confounded and not of a representative patient sample.

As the paper notes about the outcomes findings, said Udell, "there are many reasons as to why we have to take it with a grain of salt." For example, the analysis doesn't account for whether the patients were vaccinated after discharge but during the same flu season. And Medicare patients likely differ from the broader hospitalized HF population in important ways, as do GWTG-HF patients.

"We're not really seeing a large representative sample of the community that comes to the hospital with heart failure. We're seeing the tip of the iceberg, those patients who were in the heart failure registry and then declined or got vaccinated," Udell said.

"I'm not surprised that they didn't find an effect on outcomes, given all the caveats to start with."

Still, an accompanying editorial calls the lack of effect from vaccination on clinical outcomes one of the "main findings" of the analysis that "come with the strength of the largest contemporary HF sample already evaluated to address immunization efficacy."

But the editorialists, Luis Beck da Silva, MD, ScD, and Luis Eduardo Rohde, MD, ScD, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil, also point out confounders that could explain the observed lack of clinical effect.

Among them, they write, are that patients declining vaccination were excluded from outcomes analysis, as well as that the nonvaccinated patients tended to be sicker than vaccinated patients but "presumably could get greater benefit with immunization."

The outcomes analysis was for "informational purposes only," said Hernandez. "We didn't have enough data to account for the confounding that likely exists for those getting vaccinated or not," he agreed.

Vaccination and Other Quality Measures

About half of the almost 629,000 patients with an HF hospitalization from October 2012 to March 2017 were included in the vaccination trends analysis, the report notes. Excluded were those who died in-hospital, were discharged to hospice, left against medical advice, or were managed with palliative care only.

The vaccination-rate cohort also excluded patients who declined vaccination (40,072 for influenza and 55,705 for pneumococcal vaccination) and who had contraindications to vaccination.

Throughout the study period, the rate of influenza vaccination was 68% overall but decreased from 70% in the 2012-2013 flu season to 66% in the 2016-2017 flu season (P < .001). The rate of refusal of influenza vaccination increased over that period from 18% to 25% (P < .001).

The overall rate of pneumococcal vaccination was 66% but decreased from 71% to 60% from 2013 to 2016, and refusals of pneumococcal vaccination increased from 17% to 19% (P < .001 for both trends).

For the cohorts eligible for influenza and pneumococcal vaccinations, 91% and 92%, respectively, received "defect-free care" during their hospitalizations, meaning their care fulfilled all of five GWTG-HF performance measures: discharge prescription of an angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker for left ventricular ejection fraction less than 40%; discharge prescription of a β-blocker under the same circumstance; complete discharge instructions; performed or planned LVEF assessment; and smoking cessation counseling.

In multivariable analysis, defect-free care was significantly more likely at centers in the top influenza vaccination-rate quartile than in the bottom quartile: odds ratio (OR), 2.72 (95% confidence interval [CI], 1.88 - 3.94; P < .001). The same pattern was seen for pneumococcal vaccination: OR, 4.52 (95% CI, 3.06 - 6.68; P < .001).

In a subgroup of 64,614 vaccination-eligible patients matched to their fee-for-service Medicare claims data, the rate of vaccination was 89% for influenza and 86% for pneumococcal. Neither type of vaccination was significantly predictive of mortality or rehospitalization at 1 year.

Table. One-Year Outcomes Hazard Ratios by Type of Vaccination in Patients Hospitalized With HFa

Endpoints Hazard Ratio (95% CI)
Flu Vaccination Pneumococcal Vaccination
Death from any cause 0.96 (0.89 - 1.03); P = .25 0.95 (0.89 - 1.01); P = .08
Any hospitalization 0.97 (0.92 - 1.03); P = .36 1.01 (0.97 - 1.06); P = .62
aAdjusted for demographics; medical history (including atrial fibrillation, chronic obstructive pulmonary disease or asthma, diabetes, hypertension, coronary or peripheral vascular disease, stroke, cardiac implantable device therapies, anemia, renal function, depression, valvular heart disease, ischemic heart disease, smoking status, history of HF and ventricular dysfunction); and hospital characteristics (including whether teaching hospital, number of beds, US region, rural vs urban, cardiac surgery services, interventional and heart transplant capability, and number of cardiac intensive care beds).

 

Hernandez reiterated that the analysis wasn't designed to give a reliable picture of outcomes after vaccination in these patients. That, he said, will require randomized controlled trials, such as the ongoing Influenza Vaccine to Effectively Stop Cardiothoracic Events and Decompensated Heart Failure (INVESTED) trial.

INVESTED, for which both Hernandez and Udell are leading investigators, is comparing a standard-dose quadrivalent influenza vaccination against an experimental high-dose trivalent preparation in an estimated 9300 patients with a history of myocardial infarction or HF.

The primary endpoint is death from any cause or "cardiopulmonary hospitalization." Primary outcomes are expected in 2 years.

There's no placebo control group, so the trial won't clarify whether a flu shot is more cardioprotective than no flu shot in such patients.

However, said Udell, if INVESTED shows a significant reduction in hard clinical endpoints with one of the two vaccinations, in might help convince clinicians and the public of vaccination's importance as a cardiovascular treatment, and boost vaccination rates.

GWTG-HF has been funded through support from Medtronic, GlaxoSmithKline, Ortho-McNeil, and the American Heart Association Pharmaceutical Roundtable. Hernandez discloses research support from AstraZeneca, Bristol-Myers Squibb, GlaxoSmithKline, Luitpold Pharmaceuticals, Merck, and Novartis and honoraria from Bayer, Boston Scientific, and Novartis. Bhatt reports no relevant relationships. Disclosures for the other authors are in the report. Udell  disclosed research support from AstraZeneca, Janssen, Novartis, and Sanofi and honoraria from Amgen, Boehringer-Ingelheim, Janssen, Merck, Novartis, and Sanofi. Da Silva and Rohde report that they have no industry relationships or other financial disclosures.

JACC Heart Failure. Published August 8, 2018. Abstract, Editorial

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