Department of Respiratory Medicine, National Hospital Organization Fukuoka National Hospital, 4-39-1 Yakatabaru, Minami-ku, Fukuoka, 811-1394, Japan.
BMC Pulm Med. 2022 Jan 12;22(1):22. doi: 10.1186/s12890-021-01815-w.
Asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) patients experience exacerbations more frequently than those with asthma or COPD alone. Since low diffusing capacity of the lung for carbon monoxide (D) is known as a strong risk factor for severe exacerbation in COPD, D or a transfer coefficient of the lung for carbon monoxide (K) is speculated to also be associated with the risk of exacerbations in ACO.
This study was conducted as an observational cohort survey at the National Hospital Organization Fukuoka National Hospital. D and K were measured in 94 patients aged ≥ 40 years with a confirmed diagnosis of ACO. Multivariable-adjusted hazard ratios (HRs) for the exacerbation-free rate over one year were estimated and compared across the levels of D and K.
Within one year, 33.3% of the cohort experienced exacerbations. After adjustment for potential confounders, low K (< 80% per predicted) was positively associated with the incidence of exacerbation (multivariable-adjusted HR = 3.71 (95% confidence interval 1.32-10.4)). The association between low D (< 80% per predicted) and exacerbations showed similar trends, although it failed to reach statistical significance (multivariable-adjusted HR = 1.31 (95% confidence interval 0.55-3.11)).
Low K was a significant risk factor for exacerbations among patients with ACO. Clinicians should be aware that ACO patients with impaired K are at increased risk of exacerbations and that careful management in such a population is mandatory.
哮喘-慢性阻塞性肺疾病（COPD）重叠（ACO）患者比单独患有哮喘或 COPD 的患者更频繁地经历恶化。由于一氧化碳的肺弥散量低（D）已知是 COPD 严重恶化的一个强烈危险因素，因此推测 D 或一氧化碳的肺转移系数（K）也与 ACO 恶化的风险相关。
本研究是在国立医院组织福冈国立医院进行的一项观察性队列调查。在年龄≥40 岁且确诊为 ACO 的 94 名患者中测量了 D 和 K。估计了一年无恶化率的多变量调整后的风险比（HR），并比较了 D 和 K 水平之间的差异。
在一年内，队列中有 33.3%的患者经历了恶化。在调整了潜在的混杂因素后，低 K（<80%预计值）与恶化的发生呈正相关（多变量调整后的 HR=3.71（95%置信区间 1.32-10.4））。低 D（<80%预计值）与恶化之间的关联也呈现出相似的趋势，但未达到统计学意义（多变量调整后的 HR=1.31（95%置信区间 0.55-3.11））。
低 K 是 ACO 患者恶化的一个显著危险因素。临床医生应该意识到，K 受损的 ACO 患者恶化的风险增加，因此在这种人群中必须进行谨慎的管理。
