Changes in Control Status of COPD Over Time and Their Consequences: A Prospective International Study

Introduction: Control status may be a useful tool to assess response to treatment at each clinical visit in COPD. Control status has demonstrated to have long-term predictive value for exacerbations, but there is no information about the short-term predictive value of the lack of control and changes in control status over time. Method: Prospective, international, multicenter study aimed at describing the short-term (6 months) prognostic value of control status in patients with COPD. Patients with COPD were classified as controlled/uncontrolled at baseline and at 3,6-month follow-up visits using previously validated criteria of control. Moderate and severe exacerbation rates were compared between controlled and uncontrolled visits and between patients persistently controlled, uncontrolled and those changing control status over follow-up. Results: A total of 267 patients were analyzed: 80 (29.8%) were persistently controlled, 43 (16%) persistently uncontrolled and 144 (53.7%) changed control status during follow-up. Persistently controlled patients were more frequently men, with lower (not increased) body mass index and higher FEV₁(%). During the 6 months following an uncontrolled patient visit the odds ratio (OR) for presenting a moderate exacerbation was 3.41 (95% confidence interval (CI) 2.47–4.69) and OR = 4.25 (95%CI 2.48–7.27) for hospitalization compared with a controlled patient visit. Conclusions: Evaluation of control status at each clinical visit provides relevant prognostic information about the risk of exacerbation in the next 6 months. Lack of control is a warning signal that should prompt investigation and action in order to achieve control status.