Efficacy of standard rehabilitation in COPD outpatients with comorbidities

ABSTRACT: A prospective study was performed to confirm the prevalence pattern of the mostfrequent co-morbidities and to evaluate whether characteristics of patients, specific comorbiditiesand increasing number of comorbidities are independently associated with poorer outcomes in apopulation with complex chronic obstructive pulmonary disease (COPD) submitted for pulmonaryrehabilitation (PR).316 outpatients (mean¡SD age 68¡7 yrs) were studied. The outcomes recorded werecomorbidities and proportion of patients with a pre-defined minimally significant change inexercise tolerance (6-min walk distance (6MWD) +54 m), breathlessness (Medical ResearchCouncil (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 logisticregression 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 associatedwith poorer rehabilitation outcomes.KEYWORDS: Comorbidities, minimum clinically important difference, outcomes, rehabilitationComorbidities are usually defined aschronic clinical conditions associatedwith a disease process and are particularlyrelevant in elderly patients [1–4]. Chronicobstructive pulmonary disease (COPD), a commondisease in the older population, is oftenassociated with comorbidities [5–8], sharingsystemic pathological features with some of them[6, 9]. In this complex condition, comorbidities perse represent an important determinant of healthrelatedquality of life [10, 11] and clinical outcomes[12].Pulmonary rehabilitation (PR) is the only nonpharmacologicaland comprehensive interventionshowing a marked efficacy on theindividual’s functions in symptomatic COPDpatients of all grades of severity [13, 14].In a retrospective study on a wide cohort ofunselected complex COPD inpatients admitted toa single centre for a standard PR course, we wereable to show the pattern of prevalence ofcomorbidities and their impact on rehabilitationoutcomes [15]. In particular, half of these patientsreported at least one associated chronic disease,and the presence of combined metabolic and/orheart diseases reduced the PR success rate interms of exercise tolerance and quality of life.Therefore, our study has been designed prospectivelyto confirm the prevalence pattern of themost frequent comorbidities and to evaluatewhether baseline characteristics of patients, specificcomorbidities or increasing number ofcomorbidities are independently associated withpoorer outcomes in a population of COPDpatients referred to a standard outpatient PRprogramme.