Asthma–COPD Overlap Associated With High Rates of Comorbid Conditions

Comorbid conditions such as diabetes, cardiovascular disease, and eczema are highly common in individuals with asthma and chronic obstructive pulmonary disease (COPD) syndrome (asthma—COPD overlap), according to a new study published in the Annals of the American Thoracic Society.

Asthma—COPD overlap is when an individual presents symptoms and characteristics of both asthma and COPD. It has been long recognized in clinical practice, but such individuals are often excluded from clinical studies, which makes evaluating and managing this population difficult.

The term “Asthma COPD Overlap Syndrome” was first proposed in 2014 by the Global Initiative for Asthma (GINA) and the Global Initiative for Chronic Obstructive Lung Disease (GOLD) in a joint statement. GINA and GOLD mapped out 11 clinical characteristics that can be used to help identify asthma—COPD overlap, such as age, comorbid conditions, and lung function. Other groups have since issued varying criteria for the diagnosis of asthma–COPD overlap, so the prevalence of asthma–COPD overlap is unclear and varies depending on the criteria.

The study, which was conducted by the Respiratory Effectiveness Group (REG), included 2165 individuals over the age of 40 with at least 2 outpatient primary care visits over a 2-year period. The data was collected from the United Kingdom’s Optimum Patient Care Research Database. Patients were sorted in 3 groups: COPD only, both asthma and COPD, and asthma only. The criteria for asthma—COPD overlap was defined as being at least 40 years old, being a current or former smoker, and post-bronchodilator airflow limitation.

Asthma—COPD overlap’s overall prevalence in the study population was 20%. Of the individuals with asthma–COPD overlap, investigators found that the majority were men with a mean age of 70 years. All the patients were smokers (73% were former smokers, 27% were current smokers) and 66% were overweight or obese. In term of comorbid diseases, 53% had diabetes, 36% had cardiovascular disease, 21% had rhinitis, 30% had hypertension, and 23% had eczema.

Asthma—COPD overlap was most prevalent in the group of patients diagnosed with both asthma and COPD (32%). This is significantly higher than the 20% diagnosed with asthma–COPD overlap in the group just diagnosed with COPD. In the asthma only group, 14% were diagnosed with asthma–COPD overlap.

“Our observations suggest that the source population from which individuals with [asthma—COPD overlap] are identified may contribute to heterogeneity, in estimates of prevalence, demographics, clinical characteristics, and healthy outcomes” the report stated. “Additional studies are needed to confirm this.”

Reference

Krishnan JA, Nibbler A, Chisholm A, et al. Prevalence and characteristics of asthma-COPD overlap in routine primary care practices [published online June 4, 2019]. Ann Am Thorac Soc. doi: 10.1513/AnnalsATS.201809-607OC.