In recent years, healthcare providers have become more aware of the importance of educating patients with chronic diseases,1 both because of increasing interest from the patients themselves in learning about their condition, and because agents have gradually recognized that standards of treatment improve among chronic patients who are able to participate in their own care.2,3 Moreover, the availability of the Internet and smartphones have greatly increased patients’ access to health information4,5 and allowed the introduction of a new more participative and personalized care model.6

Studies have shown that individuals with chronic obstructive pulmonary disease (COPD) who receive education have a better health-related quality of life and a lower rate of hospitalization.7 Yet, surprisingly, most publications measure health outcomes in terms of hospitalizations, exacerbations, and quality of life, while the patient's knowledge of their disease is not measured either before or after participating in training programs.7,8

Several English language questionnaires have been developed that use both open-ended and leading questions to determine COPD education among patients,8–13 but until now the Spanish translations of these instruments have not been validated, nor have equivalent tools been published.

In order to provide an instrument for measuring COPD education among Spanish-speaking patients, we aimed to validate the Chronic Obstructive Pulmonary Disease Knowledge Questionnaire (COPD-Q)9 in a group of both hospitalized patients and outpatients attending hospitals in Spain. COPD-Q was designed for patients with a low general level of health literacy, a situation applicable to 50% of both the general population and COPD patients.14,15 While health literacy may affect the patient's knowledge of their diseases,13 the 13 items of the COPD-Q refer to basic knowledge that should, in principle, be routinely transmitted by healthcare professionals, and should not depend on the ability of the individual to obtain information from other sources. For this reason, we also examined differences in knowledge depending on the level of health literacy.

A total of 59 patients were enrolled, of whom 30 had low health literacy. Mean level of obstruction among the patients was severe (FEV1 43.6±18%) and the mean age was about 70 years (Table 1). Women accounted for 20% of the population (Table 1). No significant differences were observed in the general characteristics of the low and high literacy groups (Table 1), but those with lower literacy tended to be younger.

No differences were observed in EPOC-Q scores between the 2 groups (Table 1). The overall mean number of correct answers was 8.3 (SD 0.77) and the median was 8 (interquartile range of 2) (Fig. 1). None of the patients answered all items incorrectly – the minimum number of right answers was 3 – and 1 patient (1.5%) answered all 13 questions correctly (Fig. 2). The distribution of the number of correct answers was normal (P=.491) (Fig. 2). Almost all respondents (93%) knew that “people with COPD may feel short of breath”, and that “people with COPD should have a flu shot every year” (91%); in contrast, more than half believed that “people can stop taking their long-acting breathing medications (inhaler) when their COPD symptoms get better” and that “COPD can be reversed (it can go away or be cured)” (Table 2).

Fig. 1.

Box diagrams of COPD-Q scores of health literacy measured using the SAHLSA questionnaire and the cut-off point of 37 proposed by the authors.16

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Fig. 2.

Distribution of absolute frequency of right answers for each item.

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Women answered a mean of 9.2 (2.0) EPOC-Q questions correctly and men 8.1 (1.8) (P=.629); hospitalized patients answered 8.5 (1.7) questions correctly, and outpatients 8.2 (2.1) (P=.38); smokers answered 8.0 (1.9) questions correctly and non-smokers 8.9 (1.8) (P=.801). There was no significant correlation between EPOC-Q score and age, hospital center, or years since COPD diagnosis.

The internal consistency of EPOC-Q is high (Cronbach's alpha=0.825). In general, the reproducibility of each item, measured using the kappa index, was good (between 0.61 and 0.8) and in some cases excellent (between 0.81 and 1) (Table 3). Intraclass correlation coefficient between the first and second total scores was very high: 0.842 (0.745–0.904), P<.001.

The translation of the COPD-Q9 to Spanish, the EPOC-Q, is easy to administer and, in the opinion of experts and patients, all questions are easily understood. High internal consistency (Cronbach's alpha=0.825) was observed and reproducibility was good (intraclass correlation coefficient=0.842).

Although the COPD-Q was originally designed to evaluate patients with low health literacy, the EPOC-Q appears to function equally well in patients with higher health literacy, probably because, as we supposed, understanding of the items comes from information regularly imparted by healthcare professionals to all their patients.

There was only a small percentage of extreme scores (floor and ceiling effects), although most of the participants answered 2 questions correctly. One of them, “people with COPD may feel short of breath”, forms part of the daily experience of the severe COPD patient. Even so, this item should not be excluded, as it may be relevant if the questionnaire is administered to patients with milder forms of the disease, with other diseases, or healthy subjects. The other questionnaire item correctly answered by nearly all patients (“People with COPD should have a flu shot every year”) indicates a high awareness regarding influenza vaccination, which contrasts with the lack of knowledge about the benefit of maintenance therapy.

Internal consistency and reliability are similar to those of the original validation in English (Cronbach's alpha for the original: 0.72; and intraclass correlation coefficient: 0.9 [0.76–0.96]9). However, mean scores were slightly, but significantly higher (P<.001) (mean difference of 0.8 and pooled standard deviation of 1.5 points).

This study has some limitations. As no reference model for assessing COPD knowledge is available, the metrics of the English and Spanish versions cannot be compared. We believe that the differences found represent real differences in knowledge between our sample and that of the original validation, but transcultural differences cannot be fully ruled out. This uncertainty is inevitable when subjective variables are compared between 2 cultures, but this is the case for the majority of commonly used questionnaires translated from English and validated in Spanish. The EPOC-Q does not require the patient to make quantitative evaluations, since the items are answered Yes, No, or Don’t know, thus reducing cultural subjectivity. The questions are simple and were considered appropriately phrased and understandable by a panel of native-speaking experts and patients in both languages.9 It was also impossible to verify the validity of the criterion, i.e., the correlation with other ways of measuring the same construct, since no other scales of COPD knowledge have been validated in Spanish. However, the floor and ceiling effects are low, and it is our impression, based on our daily practice, that the percentage of correct answers to each question reflects what patients know and do not know about their disease. The sensitivity of the questionnaire to intervention was not evaluated, but this validation is generally performed once the questionnaire is considered acceptable from a psychometric point of view, and begins to be used by other researchers in their studies.

The practical implications of having a validated translation of the COPD-Q are clear, since this tool can be used to obtain an objective and comparable measurement of the knowledge of COPD and the impact of specific patient education. The EPOC-Q may also be useful for designing training programs tailored to address gaps in the knowledge of individual patients, taking into account that, to our knowledge, no other similar evaluation instrument has been published.

In short, the 13-item EPOC-Q questionnaire is a valid instrument that is useful and reliable for measuring COPD knowledge among patients with any level of health literacy.

The authors declare that they have no conflict of interest with the contents of this article.