Variación en la clasificación gold de los pacientes con epoc en dependencia de la escala de síntomas que se utilice

Abstract

ABSTRACT Introduction: Chronic obstructive pulmonary disease (COPD) is characterized by persistent airflow limitation. FEV₁ and FVC are not good predictors of exercise tolerance, dyspnea, and quality of life. Reports from the Global Lung Disease Organization (GOLD) proposed in 2017 a new classification for COPD that combines the symptoms and the risk of exacerbation. To assess symptoms, GOLD 2017 recommends using the Modified Medical Research Council Scale (mMRC) or the COPD Assessment Test (CAT). The main objective of our study is to determine if the assignment of a patient to a group could change depending on the symptom scale used. Other objectives to be analyzed are the concordance that exists between both methods (mMRC and CAT) and to evaluate if a score of 2 in the mMRC dyspnoea scale and a score of 10 in the CAT are equivalent. Methods: Observational study of subjects with COPD. Patients were categorized into groups: A: low risk, fewer symptoms; B: low risk, more symptoms; C: high risk, fewer symptoms; D: high risk, more symptoms. Subjects were classified twice according to and the COPD Assessment Test (CAT) and the Modified Medical Research Council Scale (mMRC). Patients with a current diagnosis of asthma, active lung infection, and interstitial lung disease were excluded. A correlation and agreement analysis was performed. A ROC curve was generated to find the CAT score that best matched the mMRC scale. Results: A total of 169 subjects were included with a mean age of 67.64 years and 68.8% were male. In our cohort, the subjects presented a mean CAT of 12.08 and a mean score on the mMRC scale of 1.09. Of the total of our sample, 126 subjects (74.6%) presented low risk according to GOLD criteria (number of exacerbations and hospitalizations). Using the mMRC dyspnoea scale to classify patients into ABCD groups we obtained that 108 (63.9%) were assigned to group A, 18 (10.7%) to group B, 25 (14.8%) to group C and 18(10.7%) to group D. When we classified the patients according to the CAT questionnaire we obtained that 61 (36.1%) were assigned to group A, 65 (38.5%) to group B, 12 (7.1%) to group C and 31 (18.3%) to group D (Figure 4). When analyzing the concordance between both GOLD groups, we obtained a value from κ of 0.492, which corresponds to a moderate concordance. In conclusion, the use of an assessment method used to measure symptoms, either the mMRC dyspnea scale or the CAT questionnaire, varies the percentage of patients assigned to one or another COPD severity category according to the GOLD guideline. These assessment methods cannot be understood as equivalent and that the cut-off point of 10 on the CAT questionnaire is not similar to a dyspnea score of 2. These data would support the idea of redefining new cut-off points and making appropriate modifications in the next GOLD update.