Efficacy of standard rehabilitation in COPD outpatients with comorbidities.

ABSTRACT: A prospective study was performed to confirm the prevalence pattern of the most frequent co-morbidities and to evaluate whether characteristics of patients, specific comorbidities and increasing number of comorbidities are independently associated with poorer outcomes in a population with complex chronic obstructive pulmonary disease (COPD) submitted for pulmonary rehabilitation (PR). 316 outpatients (mean¡SD age 68¡7 yrs) were studied. The outcomes recorded were comorbidities and proportion of patients with a pre-defined minimally significant change in exercise tolerance (6-min walk distance (6MWD) +54 m), breathlessness (Medical Research Council (MRC) score -1 point) and quality of life (St George’s Respiratory Questionnaire -4 points). 62% of patients reported comorbidities; systemic hypertension (35%), dyslipidaemia (13%), diabetes (12%) and coronary disease (11%) were the most frequent. Of these patients, .45% improved over the minimum clinically important difference in all the outcomes. In a logistic regression model, baseline 6MWD (OR 0.99, 95% CI 0.98–0.99; p50.001), MRC score (OR 12.88, 95% CI 6.89–24.00; p50.001) and arterial carbon dioxide tension (OR 1.08, 95% CI 1.00–1.15; p50.034) correlated with the proportion of patients who improved 6MWD and MRC, respectively. Presence of osteoporosis reduced the success rate in 6MWD (OR 0.28, 95% CI 0.11–0.70; p50.006). A substantial prevalence of comorbidities in COPD outpatients referred for PR was confirmed. Only the individual’s disability and the presence of osteoporosis were independently associated with poorer rehabilitation outcomes. KEYWORDS: Comorbidities, minimum clinically important difference, outcomes, rehabilitation Comorbidities are usually defined as chronic clinical conditions associated with a disease process and are particularly relevant in elderly patients [1–4]. Chronic obstructive pulmonary disease (COPD), a common disease in the older population, is often associated with comorbidities [5–8], sharing systemic pathological features with some of them [6, 9]. In this complex condition, comorbidities per se represent an important determinant of healthrelated quality of life [10, 11] and clinical outcomes [12]. Pulmonary rehabilitation (PR) is the only nonpharmacological and comprehensive intervention showing a marked efficacy on the individual’s functions in symptomatic COPD patients of all grades of severity [13, 14]. In a retrospective study on a wide cohort of unselected complex COPD inpatients admitted to a single centre for a standard PR course, we were able to show the pattern of prevalence of comorbidities and their impact on rehabilitation outcomes [15]. In particular, half of these patients reported at least one associated chronic disease, and the presence of combined metabolic and/or heart diseases reduced the PR success rate in terms of exercise tolerance and quality of life. Therefore, our study has been designed prospectively to confirm the prevalence pattern of the most frequent comorbidities and to evaluate whether baseline characteristics of patients, specific comorbidities or increasing number of comorbidities are independently associated with poorer outcomes in a population of COPD patients referred to a standard outpatient PR programme.