Evaluation of criteria for clinical control in a prospective, international, multicenter study of patients with COPD

Background The concept of clinical control in COPD has been developed to help in treatment decisions, but it requires validation in prospective studies. Method This international, multicenter, prospective study aimed to validate the concept of control in COPD [control = stability (no exacerbations or impairment in CAT scores) + low impact (low level of symptoms)]. Data from the screening visit was used to: investigate the level of control, compare characteristics of patients according to the control status, and perform a sensitivity analysis of the levels of control using either clinical criteria or questionnaires (COPD Assessment Test –CAT- or Clinical COPD Questionnaire –CCQ-). Results A total of 314 patients were analysed, mean age was 68.5 years and mean FEV1 was 52.6% of predicted. According to the prespecified criteria 21% of patients were classified as controlled, all of them with mild/moderate COPD (Body mass index, Obstruction, Dyspnea and Exacerbations, –BODEx-index <5). A high level of dyspnea, a high CAT score or an exacerbation in the previous 3 months were found, using univariate analysis, to be the main reasons for patients not being classified as controlled. Multivariate analysis showed that female sex, chronic bronchitis and having exacerbations in the previous year were associated with uncontrolled COPD. Changing the severity cut off of BODEx from 5 to 3 did not change significantly the percentage of patients fulfilling the criteria of control. Conclusions The proposed criteria of control were only fulfilled by 21% of patients. The suggested cut offs and their predictive value for poor outcomes need to be refined in prospective studies.