Epidemiology and clinical impact of major comorbidities in patients with COPD

Abstract

Comorbidities are frequent in chronic obstructive pulmonary disease (COPD) and significantly impact on patients' quality of life, exacerbation frequency, and survival. There is increasing evidence that certain diseases occur in greater frequency amongst patients with COPD than in the general population, and that these comorbidities significantly impact on patient outcomes. Although the mechanisms are yet to be defined, many comorbidities likely result from the chronic inflammatory state that is present in COPD. Common problems in the clinical management of COPD include recognizing new comorbidities, determining the impact of comorbidities on patient symptoms, the concurrent treatment of COPD and comorbidities, and accurate prognostication. The majority of comorbidities in COPD should be treated according to usual practice, and specific COPD management is infrequently altered by the presence of comorbidities. Unfortunately, comorbidities are often under-recognized and under-treated. This review focuses on the epidemiology of ten major comorbidities in patients with COPD. Further, we emphasize the clinical impact upon prognosis and management considerations. This review will highlight the importance of comorbidity identification and management in the practice of caring for patients with COPD.

Keywords: cardiovascular disease; chronic bronchitis; emphysema; mortality; prevalence.

Figure 1

Prevalence of comorbidities in COPD. Notes: Comorbidities with a prevalence of 5% or more are shown. Prevalence is calculated as a weighted average based on study sample size. ^aComorbidities with a significant increase in mortality risk compared with patients with COPD without the comorbidity; ^bcomorbidities with a significantly increased prevalence in patients with COPD compared with the general population. Data from many studies.,,,,–,–,,,,–,,, Abbreviations: AAA, abdominal aortic aneurysm; BPH, benign prostatic hypertrophy; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular accident; DVT, deep vein thrombosis; GERD, gastroesophageal reflux disease; PHT, pulmonary hypertension.

Figure 2

Interplay between COPD, major comorbidities, and symptoms. Notes: Dyspnea and cough are central features of many comorbidities. The varied ways in which COPD and the comorbidities themselves interact together are displayed. Thus, clarifying the exact cause of these symptoms (or more likely which combination of comorbidities are involved and to what extent) in such patients can be challenging. Abbreviations: COPD, chronic obstructive pulmonary disease; GERD, gastroesophageal reflux disease, IHD, ischemic heart disease; PHT, pulmonary hypertension.

Figure 3

Impact of COPD and comorbidities on mortality. Notes: The impact of each comorbidity on the mortality risk of patients with COPD is demonstrated. For example, for patients with COPD the HR of all-cause mortality associated with concurrent pulmonary hypertension (versus those with COPD alone) is 1.27–1.4. Where available for each comorbidity the reverse is also shown. For example, in patients with pulmonary hypertension the HR of all-cause mortality associated with concurrent COPD (versus those with pulmonary hypertension alone) is 1.59. ^aThis HR was not significant after adjustment for confounding risk factors. Data taken from multiple studies.,,,– Abbreviations: COPD, chronic obstructive pulmonary disease; HR, hazard ratio.

Figure 4

Comorbidities checklist. Notes: This list includes the major comorbidities, as defined by those of high prevalence or significant impact on quality of life or mortality. It may assist the physician in screening for comorbidities in the outpatient setting. Abbreviations: CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; GERD, gastroesophageal reflux disease.