[The Spanish translation and evaluation of a quality-of-life questionnaire in patients with chronic obstructive pulmonary disease].

The Chronic Respiratory Disease Questionnaire (CRDQ), proposed by Guyatt et al, is a specific instrument used to assess quality of life in patients with chronic obstructive pulmonary disease (COPD). Our aim was to translate the questionnaire and validate it so that it could then be used as a measurement instrument in programs of respiratory rehabilitation. Sixty-five patients with COPD who were candidates for breathing therapy were enrolled in the study. Mean age was 64 +/- 7 years and all had severe air flow limitation, with FEV1 33 +/- 13% over reference values but not respiratory failure (pO2 70 +/- 10 mmHg). The questionnaire was subjected to a process of translation/back translation and disagreements over wording were discussed by a panel of bilingual speakers and the author himself. The validation process involved the following steps: 1) a comprehension study with a group of 5 patients, which revealed no special difficulties; 2) analysis of internal consistency or reliability by way of Crombach's alpha coefficient, which gave and overall score of 0.92 and area scores of 0.51 for dyspnea, 0.8 for fatigue, 0.86 for emotional factors and 0.84 for disease control, and 3) analysis of correlation between various lung function parameters and exercise test results (6 min of increasing effort and a stationary cycle), which showed weak but statistically significant correlations that were comparable to those found by the author of the original CRDQ.(ABSTRACT TRUNCATED AT 250 WORDS)