Home > Medical Research Archives > Issue 149 > The Outcome of an Emergency Respiratory Admission Predicted by Forced Expiratory Flow (FEF 25–75)
Published in the Medical Research Archives
May 2019 Issue
The Outcome of an Emergency Respiratory Admission Predicted by Forced Expiratory Flow (FEF 25–75)
Published on May 28, 2019
DOI
Abstract
Background: Respiratory admissions are over-represented in emergency medical admissions; we tested whether forced expiratory flow at 25 to 75% of vital capacity (FEF25-75) reflecting small airways function, was predictive of 30-day mortality outcomes.
Methods: Between 2002 and 2017, there were 25,274 emergency admission episodes in 8071 patients with a primary respiratory diagnosis. We employed a logistic multiple variable regression model, to determine whether a pre-existing lung function measurement of (FEF25–75) was prognostic for 30-day hospital mortality, having adjusted for other outcome predictors including Acute Illness Severity and Case Co-morbidity / Complexity.
Results: Respiratory admissions represented 23.7% of all admissions but 33.3% of readmissions. FEF25–75 values linearly and inversely predicted 30-day hospital mortality outcomes - OR 0.88 (95% CI: 0.85, 0.91); consecutive deciles (falling values) of FEF25–75 demonstrated progressively rising mortality rates. Respiratory admissions with a lower FEF25–75 status were older 70.3 yr. (IQR: 60.9, 77.7) vs. 64.5 yr. (IQR: 50.3, 76.2), had a longer hospital length of stay – 6.2 days (IQR: 3.2, 10.9) vs. 5.8 days (IQR: 2.7, 7.3%) and a higher 30-day hospital episode mortality – 3.2% vs. 2.6%. The range of per patient mortality prediction was from decile 1 (lowest FEF25–75 function) 17.0% (95% CI: 14.9%, 19.1%), decile 5 of 11.7% (95% CI: 10.8%, 12.5%), and decile 10 of 7.0% (95% CI: 5.8%, 8.1%). Comorbidity interacted with the lung function estimate – the threshold to influence outcome negatively was reduced in those with lower FEF25–75 values.
Conclusion: Baseline FEF25–75 linearly and inversely predicted 30-day hospital mortality outcomes. Outcomes in those with lower FEF25–75 parameter showed Comorbidity dependence.
Key Words: Lung function, FEF25–75, Mortality Outcomes, Comorbidity Score.
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