{
  "abstract": "Background Small airway dysfunction (SAD), as assessed by impulse oscillometry (IOS) (IOS-SAD), exhibits temporal variability and its long-term fluctuations may be linked to distinct clinical phenotypes. We investigated the associations of long-term variability in IOS-SAD with adverse clinical outcomes among participants with and without chronic obstructive pulmonary disease (COPD).Methods The baseline and 2-year follow-up data from the early COPD cohort were retrospectively analysed. SAD was defined based on the following criteria: difference from R5 to R20 (R5-R20) >upper limit of normal (ULN) (R5-R20-SAD), or reactance at 5 Hz (X5) <lower limits of normal, or area under the reactance curve (AX) >ULN. Individuals were classified into three groups based on SAD variability over three visits at 2-year follow-up: (1) consistent SAD (SAD at every visit), (2) inconsistent SAD (SAD at some, but not all, visits) and (3) never SAD (no SAD at any visit). Differences in the rate of spirometric lung function decline and exacerbation rate were compared across long-term IOS-SAD variability groups in participants with and without COPD.Results In individuals with COPD, the consistent and inconsistent SAD groups assessed were associated with a faster spirometric lung function decline and a higher risk of exacerbations. In individuals without COPD, the consistent R5-R20-SAD group was associated with a faster decline in spirometric lung function and progression towards COPD.Conclusions SAD, even diagnosed once, characterises an airway behaviour with a higher proportion of higher risk of moderate or severe exacerbations. Consistent SAD was associated with accelerated spirometric lung function decline, increased exacerbation risk and progression to spirometry-defined COPD.Trial registration number ChiCTR1900024643.",
  "authors": [
    {
      "affiliations": [
        "State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China"
      ],
      "name": "Lifei Lu"
    },
    {
      "affiliations": [
        "State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China"
      ],
      "name": "Gaoying Tang"
    },
    {
      "affiliations": [
        "State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China"
      ],
      "name": "Qi Wan"
    },
    {
      "affiliations": [
        "State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China"
      ],
      "name": "Fan Wu"
    },
    {
      "affiliations": [
        "State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China"
      ],
      "name": "Zhishan Deng"
    },
    {
      "affiliations": [
        "State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China",
        "Guangzhou National Laboratory, Guangzhou, China"
      ],
      "name": "Jieqi Peng"
    },
    {
      "affiliations": [
        "State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China"
      ],
      "name": "Cuiqiong Dai"
    },
    {
      "affiliations": [
        "State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China"
      ],
      "name": "Kunning Zhou"
    },
    {
      "affiliations": [
        "State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China"
      ],
      "name": "Xiaohui Wu"
    },
    {
      "affiliations": [
        "State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China"
      ],
      "name": "Si Li"
    },
    {
      "affiliations": [
        "State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China"
      ],
      "name": "Guannan Cai"
    },
    {
      "affiliations": [
        "State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China"
      ],
      "name": "Suyin Huang"
    },
    {
      "affiliations": [
        "State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China"
      ],
      "name": "Junfeng Lin"
    },
    {
      "affiliations": [
        "Lianping County People’s Hospital, Heyuan, China"
      ],
      "name": "Shuqing Yu"
    },
    {
      "affiliations": [
        "Lianping County People’s Hospital, Heyuan, China"
      ],
      "name": "Yongqing Huang"
    },
    {
      "affiliations": [
        "Wengyuan County People’s Hospital, Shaoguan, China"
      ],
      "name": "Changli Yang"
    },
    {
      "affiliations": [
        "Wengyuan County People’s Hospital, Shaoguan, China"
      ],
      "name": "Shengtang Chen"
    },
    {
      "affiliations": [
        "State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China",
        "Guangzhou National Laboratory, Guangzhou, China"
      ],
      "name": "Pixin Ran"
    },
    {
      "affiliations": [
        "State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, National Center for Respiratory Medicine, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China",
        "Guangzhou National Laboratory, Guangzhou, China"
      ],
      "name": "Yumin Zhou"
    }
  ],
  "title": "Long-term variability of impulse oscillometry defined small airway dysfunction in participants with and without chronic obstructive pulmonary disease",
  "uid": "2e80bb5c-4f05-5343-bea0-107d266bbf9e"
}