[Secondary prevention of coronary artery disease. Flu vaccinations and new evidence of the role of infection in acute coronary syndromes]

Influenza vaccination in north Indian patients with heart failure

Background

No data exists regarding the uptake of influenza vaccination in patients with heart failure (HF) in India. The present study was designed to assess the uptake, knowledge, attitude and practices of the Indian HF patients towards influenza vaccination.

Methods and results

Five-hundred patients with acute/chronic HF were approached for a personal interview and responses to an interview recorded in a pre-defined questionnaire depicting their knowledge, attitudes and practice regarding influenza vaccination. Of the 500 approached, 320 (64%, 174 male, age 3–90 years) consented to participate in the survey. Only 7.5% (n = 24) knew of influenza as an illness with adverse potential consequences for themselves or their family. Seventeen (5.3%) were aware of potentially serious nature of influenza and 40 (12.5%) knew of the availability of a vaccine against it and its local availability. However only 14 (4.4%) had actually received the vaccine 1–2 times in the past 5 years. Only 21 (6.56%) had been prescribed influenza vaccine by their respective physicians. Reasons for declining vaccination included misperceptions about safety and efficacy of the vaccine. Most of the participants, however, had not been prescribed vaccination at all.

Conclusions

Poor influenza vaccination rates in HF mandate intense efforts to improve vaccination rates.

Influenza vaccines for preventing cardiovascular disease

BACKGROUND

This is an update of the original review published in 2008. The risk of adverse cardiovascular outcomes is increased with influenza-like infection, and vaccination against influenza may improve cardiovascular outcomes.

OBJECTIVES

To assess the potential benefits of influenza vaccination for primary and secondary prevention of cardiovascular disease.

SEARCH METHODS

We searched the following electronic databases on 18 October 2013: The Cochrane Library (including Cochrane Central Register of Controlled Trials (CENTRAL), Database of Abstracts of Reviews of Effects (DARE), Economic Evaluation Database (EED) and Health Technology Assessment database (HTA)), MEDLINE, EMBASE, Science Citation Index Expanded, Conference Proceedings Citation Index - Science and ongoing trials registers (www.controlled-trials.com/ and www.clinicaltrials.gov). We examined reference lists of relevant primary studies and systematic reviews. We performed a limited PubMed search on 20 February 2015, just before publication.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of influenza vaccination compared with placebo or no treatment in participants with or without cardiovascular disease, assessing cardiovascular death or non-fatal cardiovascular events.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by The Cochrane Collaboration. We carried out meta-analyses only for cardiovascular death, as other outcomes were reported too infrequently. We expressed effect sizes as risk ratios (RRs), and we used random-effects models.

MAIN RESULTS

We included eight trials of influenza vaccination compared with placebo or no vaccination, with 12,029 participants receiving at least one vaccination or control treatment. We included six new studies (n = 11,251), in addition to the two included in the previous version of the review. Four of these trials (n = 10,347) focused on prevention of influenza in the general or elderly population and reported cardiovascular outcomes among their safety analyses; four trials (n = 1682) focused on prevention of cardiovascular events in patients with established coronary heart disease. These populations were analysed separately. Follow-up continued between 42 days and one year. Five RCTs showed deficits in at least three of the risk of bias criteria assessed. When reported (seven studies), vaccination provided adequate immunogenicity or protection against influenza. Cardiovascular mortality was reported by four secondary prevention trials and was significantly reduced by influenza vaccination overall (risk ratio (RR) 0.45, 95% confidence interval (CI) 0.26 to 0.76; P value 0.003) with no significant heterogeneity between studies, and by three trials reporting cardiovascular mortality as part of their safety analyses when the numbers of events were too small to permit conclusions. In studies of patients with coronary heart disease, composite outcomes of cardiovascular events tended to be decreased with influenza vaccination compared with placebo. Generally no significant difference was found between comparison groups regarding individual outcomes such as myocardial infarction.

AUTHORS' CONCLUSIONS

In patients with cardiovascular disease, influenza vaccination may reduce cardiovascular mortality and combined cardiovascular events. However, studies had some risk of bias, and results were not always consistent, so additional higher-quality evidence is necessary to confirm these findings. Not enough evidence was available to establish whether influenza vaccination has a role to play in the primary prevention of cardiovascular disease.

Vacunación antigripal en pacientes con síndromes coronarios agudos: beneficio del tratamiento en diferentes subgrupos

BACKGROUND

The first prospective clinical Flu Vaccination in Acute Coronary Syndromes (FLUVACS) Trial has provided some evidence that flu vaccination together with standard therapy may be useful during the winter season to reduce the risk of death and major cardiac events in patients with acute myocardial infarction.

PATIENTS AND METHOD

Information available in the FLUVACS database was analyzed to evaluate the efficacy of flu vaccination in different subgroups. Logistic regression was used to identify features related with better therapeutic results.

RESULTS

Flu vaccination was effective in reducing the incidence of the composite endpoint (death, nonfatal myocardial reinfarction or recurrent angina prompting urgent revascularization) in most subgroups at 6 months after inclusion. The regression model showed a greater benefit of flu vaccination in patients with no ST-segment elevation or older than 65 years, nonsmokers and patients with a TIMI risk score higher than 6.

CONCLUSIONS

Our data suggest that vaccination for secondary prevention of flu during the acute phase of myocardial infarction may be effective in a broad range of patients with acute coronary artery disease, regardless of their initial clinical risk.