Flu Vaccinations Underwhelming Among Hospitalized Pneumonia Patients

is associated with a reduced risk of hospital readmission for pneumonia, according to a new study from Mount Sinai.

In new data presented at the CHEST 2019 Annual Meeting in New Orleans, a team of investigators led by Kam Sing Ho, MD, from Mount Sinai St. Luke’s and Mount Sinai West, found that nearly 12% of patients admitted with community-acquired pneumonia (CAP) were re-admitted within 30 days—nearly all of their reasons being for pneumonia, again.

In order to determine an association between in-hospital influenza vaccination on 30-day readmission, morbidity, mortality, and healthcare resource among hospitalized patients with CAP, the team conducted a retrospective study including the AHRQ-HCUP Nationwide Readmission Database from 2014.

Investigators identified adults with a principal CAP diagnosis and a vaccination procedure using ICD-9 codes. Primary outcome was all-cause readmission rates within 30 days of patient discharge, while secondary outcomes included reasons for readmission, readmission mortality rate and morbidity, and hospitalization length of stay and total costs.

Ho and colleagues identified 825,906 hospital admissions in which the primary diagnosis was CAP. Of those, just 1.91% (n = 14,047) resulted in an in-hospital flu vaccination. In 1:1 pairing of CAP patients with and without flu vaccination, investigators reported an overall 30-day readmission rate of 11.9%—with pneumonia constituting the cause of hospitalization in 98.1% of the cases.

Patients readmitted reported a twice greater mortality (7.69% vs 3.32%; P <.001), and 489,247 days were associated with hospital readmission. The economic burden reached $1 billion in costs, and $3.67 billion in charges.

In-hospital flu vaccination (HR .821; 95% CI, 0.69 — 0.98; P <.02), advanced age, Medicare coverage, atrial fibrillation, acute respiratory failure, and in-hospital oxygen use were all associated with greater risks of patient readmission.

In the 2009-2010 flu season, the H1N1 pandemic emphasized a greater burden of secondary infections driven by pneumonia, Ho and colleagues noted. Influenza and pneumococcal disease co-occurrence has been well established, and currently accounts for nearly half of all seasonal flu deaths in the US.

“Although the beneficial effects of flu vaccine are well described, this is regarded as a primary care driven service,” investigators wrote. “Only 1.91% of patients received it during their index admission for CAP, which indicates and underutilized service with significant implications on hospital readmission and mortality.”

The study, “Missed Opportunities for In-Hospital Vaccination? Influenza Vaccination Reduces 30-Day Readmission Among Patients with Community Acquired Pneumonia: A Propensity Score Match Analysis,” was presented at CHEST 2019.