Abstract
The aim of this study is to compare influenza vaccination coverage among Spaniards aged 40 y or over who suffer from chronic obstructive pulmonary disease (COPD) with those without this illness to identify the factors that influence vaccination uptake among patients with COPD.
Data was extracted from the European Health Survey performed in Spain in 2009/10, and analyzed data on 15,355 Spaniards (≥ 40 y of age), of whom 1,309 (8.2% 95%CI 7.7–8.7) had COPD was used. We considered the answer (yes/no) to the question about whether or not the interviewed person had been vaccinated against influenza in the previous flu season. We used the answer to this question as the dependent variable. For independent variables, we analyzed social demographic characteristics, health related variables, and the utilization of health care services.
Vaccination coverage among patients with COPD is 49.4% (95% CI: 46.3–52.5%) and 21.3% (95% CI: 20.7–21.9) among people without (p < 0.001). The probability of being vaccinated is three times greater for COPD patients (crude OR = 3.0, 95% CI: 2.6–3.5). Among COPD patients the uptake of vaccination increased with age. Other factors associated with an increase in vaccination coverage were: being male, perceiving one’s health as fair or poor, not smoking, and having seen a doctor during the previous month.
The rate of flu vaccination among adult Spaniards with COPD is lower than desired. Urgent strategies for increasing vaccination coverage are necessary for COPD sufferers aged under 65 of age and those with unhealthy lifestyles.
Introduction
Influenza has a high morbidity and mortality rate and leads to an increased risk of complications in those at risk.Citation1 The at risk group includes those who are older than 64 or who, though younger than 65, have certain chronic illnesses, such as COPD.Citation1,Citation2
COPD causes high mortality in developed countries, and is the fourth leading cause of death in Europe and in the United States of America.Citation3 In Spain, COPD is estimated to affect 9% of the population over 40 and 20% of the population over 65.Citation4 Lenglet et al.Citation5 have observed that in Spain, the second leading cause of hospital admissions for flu complications is COPD, preceded only by pneumonia.
In Canada, Schanzer et al.Citation6 observed that approximately 4,000 of the deaths that occur each year are attributable to influenza (a rate of 14 per 100,000 subjects), and of these deaths, 50% are patients with chronic pulmonary disease. The death rate is 12 times higher among patients with chronic pulmonary disease than among individuals who do not have this disease.Citation6
Annual influenza vaccination is the most important preventive measure recommended by public health authorities for all high risk subjects, with the objective of avoiding more serious complications, hospital admissions, and deaths.Citation7,Citation8 Studies performed in Spain and HollandCitation9,Citation10 have shown that there is a significant statistical relationship between vaccination and a decreased risk of death, these studies find a decrease of approximately 23%. Several studies have demonstrated the effectiveness of vaccination; specifically how it reduces the number of hospital admissions by 50–60% and mortality by up to 80% in older patients and those with COPD.Citation11-Citation15
The Spanish Ministry of Health, Social Welfare, and Equality recommends vaccination for all people over 64 y of age, for patients of any age with chronic illnesses, for care providers who look after people at higher risk of complications, and for health care workers.Citation16 Since 1992, influenza vaccines are offered free of charge.Citation16
The WHO, the European Union, and many authors agree that an important public health priority is the collection of national level data such as coverage and uptake predictors. This data are important as it informs quality decision making around the establishment of vaccination programs in different countries.Citation17-Citation21
In Spain, previous studies using representative samples of patients with chronic pulmonary diseases have shown vaccination coverage to be between 41% and 87%.Citation22-Citation25
Using data obtained from the European Health Survey for Spain (EHS) the objectives of our study are:
1. To compare influenza vaccination coverage among Spaniards aged 40 y or older who have COPD vs. individuals without the disease.
2. To determine the factors which influence the rate of vaccination among patients with COPD.
Results
Using the 2009 EHS database (n = 22,188), we analyzed the records of 15,355 people aged 40 y or older. A total of 1,309 people were identified as having COPD. Thus, the point prevalence of COPD was 8.2% (95%CI 7.7–8.7). shows the distribution of our study variables among patients with COPD and those who do not have the disease.
Table 1. Distribution according to the characteristics of the study participants, with and without COPD, by selected variables. EHS 2009
The patients with COPD were significantly older, included a higher percentage of men, had a lower educational level, as well as a lower monthly income than those who did not have the disease. 72.3% perceived their health as fair or poor in contrast with 37.6% of those without the disease. The prevalence of ex-smokers and obese subjects was significantly greater among patients with COPD, while the rate of physical exercise was lower. There was no significant difference with regard to alcohol consumption. All of the chronic illnesses analyzed and the variable related to the use of health care services showed significantly higher percentages among patients with COPD. and show influenza vaccination coverage in relation to the different variables analyzed.
Table 2. Influenza vaccination coverage according to social demographic variables, self rated health and tabaco use among adults with and without COPD. EHS 2009
Table 3. Influenza vaccination distribution according to lifestyle variables, chronic contitions and health service utilization among adults with and without COPD. EHS 2009
The percentage of patients with COPD who reported being vaccinated during the previous flu season was 49.4% (95% CI: 46.3–52.5%) vs. 21.3% (95% CI: 20.7–21.9) of those who did not have the disease (p < 0.001). The probability of being vaccinated is 3 times higher among patients with COPD (crude OR = 3.0 95% CI: 2.6–3.5).
The bivariate analysis for coverage among patients with COPD showed that the percentage of vaccinated patients increased significantly with age, and was highest for those patients 75 y of age or older, with vaccination rates reaching 78.2%. However, vaccination coverage was significantly lower among patients with a higher level of education and higher monthly income. There was no significant gender difference among patients with COPD.
We observed significantly higher vaccination percentages among patients with COPD who reported being non-smokers or ex-smokers compared with smokers and, among those who perceived their health as fair or poor, as well as among those who did not take part in regular physical activity.
Vaccination coverage was also significantly higher among patients with COPD who had comorbidities such as asthma, heart disease and/or stroke or diabetes, and among those who had recently sought medical attention.
Results of the multivariate analysis are shown in .
Table 4. Predictors for influenza vaccination among adult Spaniards with COPD. EHS 2009
Among COPD patients the following five factors (predictors) are independently and significantly associated with a greater probability of being vaccinated: (1) being between 65 and 74 y of age [this vaccination rate is almost 6 times (OR = 5.7) that of patients between 40 and 64 y of age]; (2) twice as many men as women are vaccinated (OR = 0.5); (3) Perceiving one’s health as fair or poor asalmost twice as many patients who perceived their health as fair or poor were vaccinated compared with those who did not perceive their health as fair or poor (OR = 1.7); (4) Being a non-smoker or an ex-smoker as non-smokers and ex-smokers were vaccinated at twice the rate of smokers (OR = 0.5); (5) those who had seen a doctor during the previous month had a vaccination rate almost double (OR = 1.7) that of those who had not sought medical attention.
Discussion
On 22 December 2009, the Council of the European Union adopted a recommendation encouraging member states to implement action plans to improve seasonal influenza vaccination coverage The main objective is to reach the WHO target of 75% vaccination coverage of risk groups by the 2014–2015 winter season. (www.epha.org/IMG/pdf/Council_Reccomendation_on_seasonal_flu_vaccine.pdf) Our principal finding is that influenza vaccination coverage among Spanish COPD patients aged over 40 y is below WHO desirable levels.
We have estimated that more than half of COPD patients (50.6%) are not vaccinated, and thus lack protection against influenza. This is extremely important because influenza infections are associated with high mortality and hospitalisation rates among COPD patients.Citation5,Citation6
Several studies consider the coverage and the predictors for influenza vaccination among patients with chronic pulmonary disease.Citation9,Citation23,Citation24,Citation26-Citation33
UK primary care consultation databases indicate that in lung disease patients influenza vaccination coverage was 36.1% among patients over 65 y of age vs. 23.8% among patients younger than 65.Citation27,Citation29 Another study in four European countries performed through telephone surveys, observed the following influenza vaccination rates among subjects older than 15 y of age with lung disease: 8% in Poland, 11% in Sweden, 20% in Germany and 30% in Spain.Citation28
In other Mediterranean European countries such as France, the 2009 annual vaccination coverage among asthma/COPD patients was 36.4% for those under the age of 65 vs. 63.3% for those over this age.Citation30
In Italy, a survey which interviewed 5935 COPD patients (aged between 15–102 y) between 2004–2005 found an overall influenza vaccine coverage of 30.5% among adults and 74.8% among older people.Citation31 Finally, data from Greece suggests that this country has lower coverage rates among all high risk (< 20% for chronic lung disease) groups than other European countries.Citation32
Several studies have been performed in Spain using primary care databases,Citation9,Citation26 and have shown influenza vaccination coverage among COPD patients at 66.8% and 64.4%, respectively, for patients over 65.
Data obtained from Spanish National Health Surveys in 2003 show vaccination coverage among COPD patients over 65 y of age at 77.8%Citation24; in 2006 rates were 77.4%Citation23. In our study which used the 2009 EHS data we found the rate to be 77.8%. From this data it can be deduced that vaccination coverage has remained stable in the last few years in Spain.
If we compare these results with those from other developed countries, we see that vaccination coverage in Spain is probably among the highest.Citation17,Citation24,Citation29-Citation36 We believe that the possible reasons for such high coverage among the older Spanish population may be as a consequence of; (1) a well-organized public health service that provides vaccination free of charge to this age group; (2) the effect of annual mass media campaigns (TV, radio, newspapers); (3) good promotion of vaccination campaigns by health care workers.Citation7,Citation22-Citation26
Several published articles specifically analyze the factors associated with a greater probability of influenza vaccination among individuals who have chronic lung disease.Citation22,Citation24,Citation25,Citation34-Citation36
The progressive increase in influenza vaccination coverage according to patient age among subjects with chronic pulmonary disease or other high risk conditions in the Spanish population can be seen in the various studies performed in Spain,Citation7,Citation24,Citation25 just as is seen in Canada, US, Germany and in other European countries within their populations.Citation33-Citation37 In both CanadaCitation33,and Germany, the vaccination rate among chronic lung disease patients increases along with patient ageCitation33,Citation35,Citation36 . In Spain it has also been demonstrated that patient vaccination coverage increases after the age of 65, and we believe that this is primarily due to the recommended vaccination of the entire population aged 65 y or more, rather than the physical condition of patients, the severity of their illnesses, or the presence of other risk factors.Citation22-Citation26
Regarding the factors we have studied related to vaccination, the multivariate analysis of COPD patients shows that more men than women are vaccinated. This result is consistent with earlier studies performed in Spain, which also found a higher rate of vaccination among men with chronic pulmonary disease,Citation22-Citation25 and work by Schoefer et al. in Germany.Citation36 However, Vozoris et al. in Canada found a higher percentage of vaccination among women.Citation33 Further studies are needed to explain these differences.
In our study, we also observed higher vaccination rates among COPD patients who are non-smokers or ex-smokers, among patients who perceive their health as fair or poor, among those who have comorbidities, and among those who had recently sought medical attention. These findings coincide with results found in earlier studies.Citation23-Citation25,Citation33,Citation36
Possible explanations for higher coverage among ex-smokers include that those who have stopped smoking may be those with more severe COPD requiring more frequent or intense advice to uptake vaccination or that they may be more concerned with the consequences of a flu infection. Alternatively, physicians may avoid recommending vaccination to those COPD patients who do not comply with smoking cessation recommendations. Finally, based on the “Health Belief Model” it follows that smoking patients believe; (1) that influenza is not dangerous; (2) that influenza vaccines are not effective and; (3) that compared with non-smokers they are not more susceptible to the disease All this highlights the necessity of information and health promotion initiatives targeted to these patients.Citation38
The multivariate analysis shows that having visited the doctor in the month prior to vaccination, or of perceiving one’s health as fair or poor, or of having received a recommendation from the doctor to get vaccinated all have a positive influence on vaccination uptake. These findings coincide with results obtained in earlier studies.Citation20,Citation22,Citation24,Citation35 Another study performed by Blank PR et al.337 in five European countries, in which the authors studied the principal factors that motivate subjects to get vaccinated, showed that the most important factor is a recommendation by a health care professional.
The significance of medical advice in ensuring influenza vaccination has also been highlighted in other Spanish studies.Citation7,Citation22-Citation26 Therefore, the role of health care workers in increasing vaccination uptake in high risk populations is essential. Improving the knowledge of HCWs on the effectiveness, security and importance of influenza vaccination is an important strategy for increasing vaccine coverage. Another organisational strategy to consider with proven effectiveness in enhancing vaccination coverage, is giving financial incentives to physicians.Citation39
In light of these results, we conclude that vaccination strategies with demonstrated effectiveness in improving coverage among high risk groups should be implemented urgently among COPD patients. Such strategies include telephone calls or personal letters, the use of databases to identify high risk patients, improving medical record keeping, designing vaccination schedules and educating patients regarding vaccinations.Citation21,Citation40-Citation42
Campaigns should also be directed at patients and designed to increase their knowledge concerning the safety, effectiveness, and benefits of vaccination.Citation40-Citation42
Finally, lowering the recommended age for universal vaccination is a public health strategy that we should consider. The evidence for this change in age limit has been argued by several authors and is based on the limited success of previous prevention policies to improve coverage among high risk groups of people under 65 y. Furthermore, several studies have shown that an age-based vaccination strategy is more effective than one based on diagnosis or clinical characteristics.Citation43-Citation46
Our study has several limitations. First of all, the validity of the questions used by the EHS to classify COPD patients’ vaccination status has not been evaluated. However, several studies comparing patient answers to medical questions with information in patient medical records show a high degree of sensitivity and agreement.Citation47,Citation48 Second, the information obtained may be subject to memory errors or the desire to provide socially acceptable answers. Third, the information regarding relevant variables such as pharmacologic treatment, the use of other recommended vaccinations (pneumococcal vaccine) or the duration and severity of the COPD, are not included in the EHS and may act as confounding factors. In conclusion, the rate of flu vaccination among adult Spaniards with COPD is lower than the desired WHO target. Urgent strategies for increasing vaccination coverage are necessary for COPD sufferers aged under 65 and for those with unhealthy lifestyles.
Materials and Methods
A cross sectional epidemiological study on influenza vaccination was performed using individual patient data obtained from the European Health Survey for Spain conducted in 2009.
The European Health Interview Survey (EHIS) is a comprehensive and coordinated survey performed within the European Union countries every five years (1st wave: 2007–2009) under the responsibility of Eurostat. The aim of this project is to provide nationwide representative data of non-institutionalised people aged 16 y or over living in each country permitting comparison between different European populations.Citation49
Tri-stage sampling was used, with stratification of the items in the first stage (census sections) having a probability proportional to the size of the section (Stratum used: over 500,000 inhabitants; 500,000–100,000 inhabitants; 50,000 a 100,000 inhabitants; 20,000–50,000 inhabitants; 10,000–20,000 inhabitants and less of 10,000 inhabitants)The items in the second stage (family dwelling) were selected using a systematic sampling with random starting and equal probability for selection for each family dwelling in the section. Family dwelling refers to households where one or more individuals live. If two or more families live in the same household they would be considered as two or more independent family dwellings (this was extremely infrequent). The estimated number of family dwellings in each census section was provided by the National Institute of Statistics (INE). The total number of census sections selected after stratification were 1,927 with 12 households for each, so finally the total number of households was 23,124. In the third stage all adults (> 15 y) living in the selected family dwelling were eligible to participate in the survey but among those only one was randomly selected to complete the questionnaire. Therefore all those living in the family dwelling had an identical probability of participating.
The information was compiled between April, 2009 and March 2010. The questionnaire for data collection was administered by an interviewer at the household.
The inclusion criteria for the EHS included: age over 15 y, residing in the household at the time the survey was conducted and providing informed consent. Exclusion criteria were: not being able to understand or answer the questions or no one else in the household was qualified to complete the questionnaire for the person selected. Details of the EHS methodology are available elsewhere.Citation50
The total EHS sample was 22,188 individuals, for study purposes we selected all Spaniards aged over 40 y recorded in this database (15,355).
In our study, subjects were classified as COPD patients if they responded affirmatively to at least one of the following questions: “Has a doctor diagnosed you as having COPD?” “Have you taken medication for COPD in the last two weeks?” Information on influenza vaccination uptake was self-reported and collected using the question “Have you received the influenza vaccine in the previous season?” The vaccination status was not verified using documentary evidence.
Vaccination information refers exclusively to seasonal influenza vaccine (pandemic influenza was available in Spain from November 2009), and this was explicitly explained to the subject during the interview.
As independent variables, we analyzed: (a) social demographic characteristics (age, gender, marital status, age at completion of formal education, and monthly income); (b) health related variables (self-rated health, diabetes, heart disease and/or stroke, depression and/or anxiety, obesity, tobacco use, alcohol consumption, physical exercise) and (c) the utilization of health care services (visits to the doctor in the last four weeks, hospital admissions in the last 12 mo, emergency room visits in the last 12 mo).
| Abbreviations: | ||
| Chronic obstructive pulmonary disease | = | COPD |
Acknowledgments
This study forms part of a research project funded by “Carlos III Institute FIS” grant PS09/01609.
Statistical analysis
First, we estimated the prevalence of Spanish adult COPD sufferers, described their distribution according to the study variables, and compared these figures against those for the non COPD population. Second, we estimated and compared vaccination coverage, among COPD and non COPD sufferers, according to social demographic characteristics, health related variables and utilization of health care services. Crude Odds Ratios with 95% confidence intervals were estimated to compare coverage among those with and without COPD using bivariate logistic regression.
The χ2 statistical method was used for bivariate comparison of proportions, and statistical significance was set at two-tailed α < 0.05.
Third, multivariate logistic regression models were generated so that, by using influenza vaccination as the dependent variable, we could determine which of the variables covered was independently associated with influenza vaccination (predictors) among COPD sufferers. In the model we included those variables that yielded a significant association in the bivariate analysis.
Estimates were made using the “svy” (survey commands) functions of the STATA program, which enabled us to incorporate the sampling design and weights into all our statistical calculations (descriptive, Chi-square, logistic regression).
Disclosure of Potential Conflicts of Interest
No potential conflicts of interest were disclosed.All information regarding health related variables, including morbidity, lifestyle or health service utilization, was self-reported and was not checked with any other documentary source.
Following Spanish legislation, it was not necessary to have ethics committee approval as this analysis was conducted on de-identified, public-use data sets.
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