Asthma-COPD overlap (ACO) is a heterogeneous condition that describes patients who show persistent airflow limitation with clinical features that support both asthma and COPD. Although no single consensus definition exists to diagnose this entity, common major criteria include a strong bronchodilator reversibility or bronchial hyperreactivity, a physician diagnosis of asthma, and a ≥ 10-pack-year cigarette smoking history. The prevalence of ACO ranges from 0.9% to 11.1% in the general population, depending on the diagnostic definition used. Notably, patients with ACO experience greater symptom burden, worse quality of life, and more frequent and severe respiratory exacerbations than those with asthma or COPD. The underlying pathophysiologic features of ACO have been debated. Although emerging evidence supports the role of environmental and inhalational exposures in its pathogenesis among patients with a pre-existing airway disease, biomarker profiling and genetic analyses suggest that ACO may be a heterogeneous condition, but with definable characteristics. Early-life factors including childhood-onset asthma and cigarette smoking may interact to increase the risk of airflow obstruction later in life. For treatment options, the population with ACO historically has been excluded from therapeutic trials; therefore strong, evidence-based recommendations are lacking beyond first-line inhaler therapies. Advanced therapies in patients with ACO are selected according to disease phenotypes and are based on extrapolated data from asthma and COPD. Research focused on defining biomarkers and evidence-based treatment options for ACO is needed urgently.

哮喘-慢性阻塞性肺病重叠 (ACO) 是一种异质性疾病，描述了表现出持续气流受限且临床特征支持哮喘和慢性阻塞性肺病的患者。虽然没有单一的共识定义来诊断该实体，但常见的主要标准包括强支气管扩张剂可逆性或支气管高反应性、哮喘的医生诊断和 ≥ 10 包年的吸烟史。根据所使用的诊断定义，普通人群中 ACO 的患病率从 0.9% 到 11.1% 不等。值得注意的是，与哮喘或慢性阻塞性肺病患者相比，ACO 患者的症状负担更大、生活质量更差、呼吸系统恶化更频繁、更严重。ACO 的潜在病理生理特征一直存在争议。尽管新出现的证据支持环境和吸入暴露在已存在气道疾病的患者发病机制中的作用，但生物标志物分析和遗传分析表明 ACO 可能是一种异质性疾病，但具有明确的特征。包括儿童期哮喘和吸烟在内的早期生活因素可能会相互作用，从而增加晚年气流阻塞的风险。对于治疗选择，历史上患有 ACO 的人群被排除在治疗试验之外；因此，除了一线吸入器疗法外，还缺乏强有力的、基于证据的建议。ACO 患者的先进疗法是根据疾病表型选择的，并基于哮喘和 COPD 的外推数据。