Role of comorbidities in a cohort of patients with COPD undergoing pulmonary rehabilitation

Abstract

Background: Chronic obstructive pulmonary disease (COPD) is often associated with other chronic diseases. These patients are often admitted to hospital based rehabilitation programmes. Objectives: To determine the prevalence of chronic comorbidities in patients with COPD undergoing pulmonary rehabilitation and to assess their influence on outcome. Design: Observational retrospective cohort study. Setting: A single rehabilitation centre. Patients: 2962 inpatients and outpatients with COPD (73% male, aged 71 (SD 8) years, forced expiratory volume in 1 s (FEV 1 ) 49.3 (SD 14.8)% of predicted), graded 0, 1 or >2 according to the comorbidity categories and included in a pulmonary rehabilitation programme. Measurements: The authors analysed the number of self-reported comorbidities and recorded the Charlson Index. They then calculated the percentage of patients with a predefined positive response to pulmonary rehabilitation (minimum clinically important difference (MCID)), as measured by improvement in exercise tolerance (6 min walking distance test (6MWD)), dyspnoea (Medical Research Council scale) and/or health related quality of life (St George's Respiratory Questionnaire (SGRQ)). Results: 51% of the patients reported at least one chronic comorbidity added to COPD. Metabolic (systemic hypertension, diabetes and/or dyslipidaemia) and heart diseases (chronic heart failure and/or coronary heart disease) were the most frequently reported comorbid combinations (61% and 24%, respectively) among the overall diseases associated with COPD. The prevalence of patients with MCID was different across the comorbidity categories and outcomes. In a multiple categorical logistic regression model, the Charlson Index (OR 0.72 (96% CI 0.54 to 0.98) and 0.51 (96% CI 0.38 to 0.68) vs 6MWD and SGRQ, respectively), metabolic diseases (OR 0.57 (96% CI 0.49 to 0.67) vs 6MWD) and heart diseases (OR 0.67 (96% CI 0.55 to 0.83) vs SGRQ) reduced the probability to improve outcomes of rehabilitation. Conclusions: Most patients with COPD undergoing pulmonary rehabilitation have one or more comorbidities. Despite the fact that the presence of comorbidities does not preclude access to rehabilitation, the improvement in exercise tolerance and quality of life after rehabilitation may be reduced depending on the comorbidity.Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality.

Objectively identified comorbidities in COPD: impact on pulmonary rehabilitation outcomes

“…Osteoporosis, heart disease and metabolic disease have been shown to be positively or negatively associated with changes in 6MWD and SGRQ scores following PR [3,4]. We were not able to corroborate these findings.…”

“…The deleterious effects of comorbid chronic obstructive pulmonary disease (COPD) and obstructive sleep apnoea (OSA) have long been recognised and are frequently encountered as a clinical scenario [1,2]. Although continuous positive airways pressure can be used in order to abolish upper airways obstruction in OSA, it can have adverse effects on pulmonary mechanics in patients with airways obstruction [3]. Auto-titrating modes of noninvasive ventilation (NIV) that monitor tidal volume, respiratory rate and upper airway patency and can vary back up rate, inspiratory and expiratory positive airway pressure (IPAP and EPAP, respectively) may have clinical benefits.…”

“…We were not able to corroborate these findings. In our study, comorbidities were assessed using objective measures, while most previous studies used "self-reports" or data from medical records [3,4]. Moreover, previous studies used a different threshold to classify an improvement in 6MWD as clinically relevant (i.e.…”

“…Moreover, previous studies used a different threshold to classify an improvement in 6MWD as clinically relevant (i.e. 54 m) [3,4].…”

The importance of components of pulmonary rehabilitation, other than exercise training, in COPD

“…Furthermore, there is now recognition of the prevalence of multi-comorbidity amongst people with COPD. That is, more than half of all people with COPD who have been referred to a pulmonary rehabilitation programme have at least one other chronic condition [30] and, therefore, medication burden in this group is likely to be high. Among elderly adults who have been prescribed multiple medications, nonadherence to pharmacotherapy regimens is problematic [31], which, in turn, increases the risk of hospitalisation and mortality [32].…”