Influenza vaccination coverage and related factors among Spanish patients with chronic obstructive pulmonary disease

Abstract

This study sought: to describe influenza vaccination coverages among COPD patients treated in a primary-care setting; and to analyse the factors linked to compliance with vaccination recommendations.

This was a descriptive study in a primary-care (PC) setting. Each of the 2422 randomly selected medical practitioners included in the study was required to recruit five COPD patients. Information was drawn from patients’ clinical histories and personal interviews. As the dependent variable, we took the answer (yes or no) to the question, “did you have an influenza vaccination in the most recent campaign?”; and as independent variables, we analysed socio-demographic data, health-status related variables, lifestyles and history of pneumococcal vaccination.

A total of 10,711 patients were enrolled 87.2% reported having been vaccinated in the most recent campaign. In conclusion, Spanish COPD patients treated in a primary-care setting can be said to enjoy good vaccine coverages against the influenza virus. More frequent contact with the general practitioner and a history of pneumococcal vaccination increase the likelihood of being vaccinated considerably, and measures should be implemented with the aim of improving coverages among younger subjects and those who lead less healthy lifestyles.

Introduction

Sufferers from chronic obstructive pulmonary disease (COPD) are a target group for influenza vaccination because they run a high risk of suffering influenza-induced complications [1]. The importance of COPD sufferers as a target group derives from the disease's high prevalence and the fact that risk of influenza-related hospitalisation and death has been shown to be high among such persons at any age [2], [3], [4], [5], [6].

Worldwide prevalence of COPD has been estimated at 9.34/1000 cases among men and 7.33/1000 cases among women of all ages [2]. In the United States, 10.2 million adults (5.9% of the adult population) were estimated to be affected by COPD in 1997 [3]. In Spain, a prevalence of 9.1% (95% CI: 8.1–10.2%) in the general population aged 40–69 years was reported by the IBERPOC study [4].

The effectiveness of influenza vaccination in patients with chronic respiratory diseases has been demonstrated by clinical trials and observational studies [7], [8], [9], [10], [11]. A recently published clinical trial reported an overall vaccine efficacy of 76% in terms of reducing the appearance of acute respiratory episodes among patients diagnosed with COPD, based on figures of 84, 45 and 85% for subjects with mild, moderate and severe COPD respectively [7]. A cohort study analysed influenza vaccination among persons over the age of 65 years with chronic pulmonary disease, and observed significant reductions in pneumonia- and influenza-related hospitalisations (RR 0.48; 95% CI: 0.28–0.82) and mortality (RR 0.30; 95% CI: 0.21–0.43) during the influenza seasons among vaccinated subjects [9]. Vaccination was also associated with a lower number of outpatient visits due to pneumonia and other respiratory processes [9].

As is the case in most developed countries, the Ministry of Health and Consumer Affairs in Spain recommends annual influenza vaccination for subjects who suffer from COPD, irrespective of their age, and administers the vaccine free of charge [1], [12].

A number of authors have stressed the usefulness and importance of the study of influenza vaccine coverages and (predictive or determining) factors associated with such vaccination [13], [14], [15], [16], [17].

Coverage studies enable compliance with prevailing guidelines to be ascertained, associated factors studied, and non-complying subjects characterised and identified [13], [14], [15], [16], [17]. Furthermore, these studies are of help for the purposes of drawing up appropriate strategies to improve goals, provide data in support of decision-making and manage vaccination programmes [13], [14], [15], [16], [17]. Among its priority goals, the WHO's global agenda for influenza surveillance and control includes developing and implementing methods for measurement of and feedback about the progress of national and local programmes for influenza control, including vaccine use [18], [19].

In Spain and the remaining European countries alike, most data on influenza coverage tends to focus on subjects aged 65 years and over [12], [16]. In a recent study, in which 26 European countries were asked about vaccine coverages among groups deemed to be at risk for having associated chronic diseases, regardless of age, only 3 countries had official data [16].

The most recent study conducted in Spain indicates that among subjects with associated chronic diseases (respiratory and heart diseases, and diabetes), coverages are 40.7 and 60.3% for the 50–64 and over-64 age groups, respectively [20].

Similarly, studies on vaccination-related factors undertaken in Spain to date have fundamentally centred on the general population, and the over-64 age group in particular [20], [21], [22], [23], [24], [25], [26].

This study sought: to describe influenza vaccination coverages among COPD patients treated in a primary-care setting; and to analyse the factors linked to compliance with vaccination recommendations.