Frequency of Comorbidities in Chronic Obstructive Pulmonary Disease, and Impact on All-cause Mortality: A Population-based Cohort Study

Background: In chronic obstructive pulmonary disease (COPD), the role of specific comorbidities on all-cause mortality is of major interest particularly with a database representative of the beneficiaries covered by the French health system. We investigated the frequency and the role of major comorbidities on all-cause mortality in a population-based cohort of COPD patients, and whether this impact was modulated by gender.

Methods: A historical cohort was identified in the French claims data. Patients aged ≥45 years were selected in 2006 from the French national claims data (1/97(th) random sample) by at least one of the following criteria: (a) COPD-related hospitalisations, (b) long-term disease status for COPD, (c) dispensations of bronchodilators. Cardiovascular diseases, diabetes, depression and cancer were defined by specific therapy and/or long-term disease status. The impact of comorbidities on mortality was investigated during a seven-year follow-up period (2007-2013), using Cox models.

Results: In 4,237 patients (mean age 68 years, 55% males, mean annual death-rate 4.9%), cardiovascular diseases, diabetes, depression and cancers were identified in 68.7%, 15.2%, 14.2% and 10.6% of patients, respectively. Associations with mortality were significant for cardiovascular diseases (HR = 1.2, 95%CI = [1.0-1.4]), diabetes (HR = 1.2, 95%CI = [1.0-1.4]), depression (HR = 1.4, 95%CI = [1.2-1.6]) and cancers (HR = 1.6, 95%CI = [1.4-1.9]), with no difference between genders.

Conclusions: In the French population, major comorbidities are common in COPD, particularly cardiovascular diseases that occur in over two thirds of patients. The impact of comorbidities on mortality was not related to their prevalence, with cancer having the largest impact.