[Validation of the Spanish version of the Chronic Obstructive Pulmonary Disease-Population Screener (COPD-PS). Its usefulness and that of FEV₁/FEV₆ for the diagnosis of COPD].

BACKGROUND AND OBJECTIVES

The chronic obstructive pulmonary disease (COPD) is a highly undiagnosed disease. The use of short screening questionnaires designed to detect chronic airflow obstruction may help to the early diagnosis of COPD.

PATIENTS AND METHOD

This was an observational, cross-sectional epidemiological study aimed to validate the translated into Spanish version of the COPD-PS questionnaire. Socio-demographic and clinical data of participants were collected, as well as their answers to the COPD-PS and EQ-5D questionnaires. The ratio FEV(1)/FEV(6) was measured with the COPD-6 device. The psychometric properties of the questionnaire and the diagnostic yield of the FEV(1)/FEV(6) ratio were analysed, both referred to the gold standard of post-bronchodilator FEV(1)/FVC < 0.7.

RESULTS

Ten primary care centers participated in the study and included 94 controls and 79 cases with chronic airflow obstruction. Questionnaire characteristics were: feasibility, 2.3% of participants did not answer at least one item; mean time to fill the questionnaire was 47.7 seconds; 4.7% of individuals had a 0 score. Validity, moderate correlation with EQ-5D scores and moderate-high with FEV(1); the scores of COPD-PS were related to all parameters associated with COPD. A cut off of 4 units had the best sensitivity/specificity ratio and correctly classified 78% of participants. For the FEV(1)/FEV(6) ratio, a cut off of 0.75 correctly classified 85% of individuals.

CONCLUSIONS

The COPD-PS questionnaire demonstrated good psychometric properties. A cut off score of 4 has excellent predictive value. A ratio of 0.75 in the FEV(1)/FEV(6) provides an excellent correlation with the ratio FEV(1)/FVC and is useful for the identification of individuals with chronic airflow obstruction.