Prevalence and disparities in influenza vaccination among patients with COPD: A French nationwide population study

Despite concordant international recommendations, many surveys found disappointing rates of influenza vaccination in at-risk populations, ranging from 23% in overall COPD population to more than 70% in more severe COPD subjects. Therefore, we assessed the proportion of French COPD patients non-vaccinated for influenza and their clinical and socio-demographic factors.

This was a national retrospective study based on the French health insurance database. We identified "diagnosed COPD", defined as subjects hospitalized at least once in 2017 with a principal or associated diagnosis of COPD, and "suspected COPD" as those who were prescribed at least thrice long-acting bronchodilators (LAB), after exclusion of patients with a principal diagnosis or secondary associated diagnosis of asthma or cystic fibrosis, patients deceased before the influenza season and patients hospitalized in long-term or in palliative care unit. Multivariate logistic regression was used to assess the association between patients' characteristics and the lack of influenza vaccination.

From the national database, 1 474 396 subjects were identified as "suspected COPD" of whom 528 114 were excluded because of previous diagnosis of asthma or cystic fibrosis, and 350 566 as "diagnosed COPD". Among the 1 296 848 patients included, 646 687 patients (53.3%) were vaccinated against influenza. Non-vaccinated subjects were significantly younger (62.1 vs 71.6 years old), more often women (47.9% vs 43.1%) and had fewer comorbidities assessed by Charlson's index (3.0 ± 2.2 vs 4.3 ± 2.1). Lack of vaccination was also associated with a lower LAB usage. Also, non-vaccinated subjects neither had severe exacerbation during the study period. Besides there was a significant heterogeneity in vaccination rate by geographic region, from 47% to 57%. In multivariate analysis, variables independently associated with the lack of influenza vaccination were female gender, younger age, fewer comorbidities and lower socio-economic level.

This study using the French exhaustive health insurance database shows that influenza vaccination among COPD patients remains dramatically low and must become a high-priority public-health strategy.