Obstructive Spirometric Index for Asthma Attack Risk Prediction: Analysis from the ORACLE2 Patient-Level Meta-Analysis
Abstract
RATIONALE: Low lung function is a key risk factor for asthma attacks. While forced expiratory volume in 1 second (FEV₁) is widely used, it lacks specificity. Incorporating the FEV₁/forced vital capacity (FEV₁/FVC) ratio may better capture obstruction. AIM: To develop an index integrating FEV₁ and FEV₁/FVC to assess asthma attack risk. METHODS: Using ORACLE2, a patient-level meta-analysis of randomised trials’ control arms, we applied a multivariable negative binomial model assessing the combined impact of FEV₁ (% predicted) and FEV₁/FVC (% predicted) on asthma attack risk. The Obstructive Spirometric Index (OSI) was derived from their relative excess risk. OSI, FEV₁, and FEV₁/FVC’s prognostic values were compared across quartiles. RESULTS: Among 5,221 participants (17 trials), both FEV₁ (adjusted rate ratio [aRR] per 10% decrease: 1.05 [1.00–1.09]) and FEV₁/FVC (aRR per 10% decrease: 1.09 [1.03–1.16]) were independent predictors of attack risk. The OSI classification was derived so that the prognostic’s value equaled the aRR for asthma attacks (OSI = 1.15, 15% greater attack risk)(Figure). OSI outperformed FEV₁ and FEV₁/FVC, with a higher aRR across Q2–Q4 vs. Q1 (not shown). CONCLUSIONS: OSI improves asthma attack risk stratification beyond FEV₁ and FEV₁/FVC alone, quantifying risk independently of other clinical and inflammatory parameters. PROSPERO: CRD42021245337; FUNDING: NIHR,FRQS,APQ erj;66/suppl_69/PA1473/F1 F1 F1
Authors 25
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Affiliation as printed
1Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Canada
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Leiden University · Leiden University Medical Center
Affiliation as printed
2Dept. of Biomedical Data Sciences, Leiden University Medical Centre, Leiden, Netherlands
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The University of Western Australia · Institute for Respiratory Health
Affiliation as printed
3lnstitute for Respiratory Health & UWA Medical School, University of Western Australia, Perth, Australia
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4National Jewish Health, Denver, United States
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5Department of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium
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University of California, Los Angeles
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6UCLA, Los Angeles, United States
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University of Leicester · NIHR Leicester Biomedical Research Centre
Affiliation as printed
7Department of Respiratory Sciences, lnstitute for Lung Health, NIHR Respiratory BRC, University of Leicester, Leicester, United Kingdom
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University of Leicester · NIHR Leicester Biomedical Research Centre
Affiliation as printed
7Department of Respiratory Sciences, lnstitute for Lung Health, NIHR Respiratory BRC, University of Leicester, Leicester, United Kingdom
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Affiliation as printed
8Pulmonary Critical Care & Sleep Medicine. Univ of Kansas, Kansas, United States
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Affiliation as printed
9Baylor College of Medicine, Houston, United States
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Guy's Hospital · St Thomas' Hospital
Affiliation as printed
10Guy's Severe Asthma Centre, Guy's and St Thomas·Hospitals, London, United Kingdom
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Affiliation as printed
11AstraZeneca, Cambridge, United Kingdom
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Affiliation as printed
11AstraZeneca, Cambridge, United Kingdom
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GlaxoSmithKline (United Kingdom)
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12GlaxoSmithKline, London, United Kingdom
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Affiliation as printed
13Sanofi, Cambridge, United States
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Affiliation as printed
1Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Canada
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Affiliation as printed
14Genentech, San Francisco, United States
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Affiliation as printed
15Novartis, Hyderabad, India
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16Respiratory Medicine Unit and Oxford Respiratory NIHR BRC, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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Medical Research Institute of New Zealand
Affiliation as printed
17Medical Research lnstitute of New Zealand, Wellington, New Zealand
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Medical Research Institute of New Zealand
Affiliation as printed
17Medical Research lnstitute of New Zealand, Wellington, New Zealand
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Jacob K. Sont Aachen
Leiden University · Leiden University Medical Center
Affiliation as printed
18Dept. of Biomedical Data Sciences. Leiden University Medical Centre, Leiden, Netherlands
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Leiden University Medical Center
Affiliation as printed
19Julius Center, University Medical Center, Leiden, Netherlands
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Affiliation as printed
16Respiratory Medicine Unit and Oxford Respiratory NIHR BRC, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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Affiliation as printed
1Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Canada
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