Questionnaires in Multidimensional Assessment of Chronic Obstructive Pulmonary Disease: Two Sides of the Same Coin

Abstract

In recent decades, the diagnosis of chronic obstructive ulmonary disease (COPD) has been veering from simple oneimensional schemes to more complex strategies based on ultidimensional approaches or on phenotypes. The latest update f the GOLD1 strategy recommends the use of three questionnaires or the assessment of the patient’s situation: the COPD Assessment est (CAT),2 the modified Medical Research Council (MRC) dyspnea cale,3 and the Clinical COPD Questionnaire (CCQ).4 The inclusion of hese three different questionnaires in the GOLD strategy to assess he impact of the disease in patients has provoked an interesting ebate on the multidimensional assessment of the disease. In order to verify the equivalence of these questionnaires, sevral authors have conducted observational studies, describing a eality that was intuitively perceived by the clinician: the results f these questionnaires, while individually valid in assessing the mpact of the disease, are not superimposable. In this respect, some tudies have highlighted a lack of agreement between CAT and RC,5 while others report the discrepancies between the MRC nd the St. George’s respiratory questionnaire.6 The differences are educed by changing the cutoff for the MRC questionnaire in the OLD classification. Thus, Jones et al.7 suggest that if patients with nd without dyspnea (MRC grade 0) are separated, the distribuion of patients over the various GOLD types is very similar to that btained using CAT with the current cutoff values. The idea behind these studies is that if the classification perentages with both scales in a given patient cohort agree, then they ould all be used interchangeably for categorizing COPD patients. owever, as Jones et al.7 point out, concordance in the distribuion of GOLD types does not necessarily mean that patients who btain the same scores on the different questionnaires using these ew cutoff values will be exactly the same. In this respect, it should