Clinical characteristics of the asthma–COPD overlap syndrome – a systematic review

Abstract

Background and objectiveIn recent years, the so-called asthma–chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) has received much attention, not least because elderly individuals may present characteristics suggesting a diagnosis of both asthma and COPD. At present, ACOS is described clinically as persistent airflow limitation combined with features of both asthma and COPD. The aim of this paper is, therefore, to review the currently available literature focusing on symptoms and clinical characteristics of patients regarded as having ACOS.MethodsBased on the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, a systematic literature review was performed.ResultsA total of 11 studies met the inclusion criteria for the present review. All studies dealing with dyspnea (self-reported or assessed by the Medical Research Council dyspnea scale) reported more dyspnea among patients classified as having ACOS compared to the COPD and asthma groups. In line with this, ACOS patients have more concomitant wheezing and seem to have more cough and sputum production. Compared to COPD-only patients, the ACOS patients were found to have lower FEV1% predicted and FEV1/FVC ratio in spite of lower mean life-time tobacco exposure. Furthermore, studies have revealed that ACOS patients seem to have not only more frequent but also more severe exacerbations. Comorbidity, not least diabetes, has also been reported in a few studies, with a higher prevalence among ACOS patients. However, it should be acknowledged that only a limited number of studies have addressed the various comorbidities in patients with ACOS.ConclusionThe available studies indicate that ACOS patients may have more symptoms and a higher exacerbation rate than patients with asthma and COPD only, and by that, probably a higher overall respiratory-related morbidity. Similar to patients with COPD, ACOS patients seem to have a high occurrence of comorbidity, including diabetes. Further research into the ACOS, not least from well-defined prospective studies, is clearly needed.

Identifying possible asthma–COPD overlap syndrome in patients with a new diagnosis of COPD in primary care

“…13–15 However, the criteria for ACOS differs between studies, 30 as some are based on symptoms and spirometric parameters, 28,31 others on the presence of a physician’s diagnosis of both asthma and COPD, 13,32–34 and some on a mixture of these criteria. 14,35 …”

Asthma-COPD Overlap Syndrome: What We Know and What We Don't

“…Rhee et al36 in Korea have shown that individuals with ACOS were likely to use emergency rooms and be hospitalized for their respiratory condition compared with individuals with COPD alone. The two large systematic reviews and meta-analyses conducted on ACOS have affirmed these findings by demonstrating that patients with ACOS have greater symptomatic burden and require greater health care utilization including emergency department visits and hospitalization than individuals with COPD alone3745.…”

Treatment trends in patients with asthma–COPD overlap syndrome in a COPD cohort: findings from a real-world survey

“…Patients with ACOS experience more severe symptoms than those with either asthma or COPD alone, with more frequent and more severe exacerbations5 and more frequent hospitalizations 4. Patients with ACOS have been shown to be significantly younger than those with COPD, with a higher body mass index (BMI),6 and greater medical resource utilization and economic burden 7,8…”