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Prognostic value of ventilatory efficiency in hypersensitivity pneumonitis
Worawat Chumpagern1, Paolo Spagnolo2, Pailin Ratanawatkul1
1Division of Pulmonary and Critical Care Medicine, Khon Kaen University Faculty of Medicine, Khon Kaen, Thailand.
BMJ Open Respiratory Research
|July 9, 2026
Summary
Ventilatory efficiency (VE) measured by VE/carbon dioxide (VE/VCO2) slope is linked to disease severity in hypersensitivity pneumonitis (HP). An elevated VE/VCO2 slope predicts mortality, suggesting its use as a prognostic marker in HP patients.
Area of Science:
- Pulmonary Medicine
- Cardiopulmonary Exercise Testing
- Respiratory Diseases
Background:
- Ventilatory efficiency (VE) is a key prognostic indicator in cardiopulmonary diseases.
- The prognostic value of VE in hypersensitivity pneumonitis (HP) is not well-established.
- This study investigates the correlation between VE and disease severity, and its predictive value for mortality in HP.
Purpose of the Study:
- To determine if ventilatory efficiency (VE) correlates with disease severity in patients with hypersensitivity pneumonitis (HP).
- To assess whether VE predicts mortality in patients with HP.
- To explore the relationship between VE and clinical parameters like pulmonary fibrosis, pulmonary hypertension, and lung function.
Main Methods:
- Retrospective cohort study of 164 patients with non-fibrotic HP (nfHP), fibrotic HP (fHP), and idiopathic pulmonary fibrosis (IPF) from 2009-2019.
- Cardiopulmonary exercise testing (CPET) assessed ventilatory efficiency (VE/carbon dioxide [VE/VCO2] slope and nadir).
- Multivariate logistic regression and Kaplan-Meier plots analyzed predictors of 5-year mortality.
Main Results:
- Elevated VE/VCO2 slope and nadir correlated with decreased diffusing capacity for carbon monoxide (DLCO%) but not forced vital capacity (FVC%).
- Patients with pulmonary hypertension (PH) and fHP or IPF showed significantly higher VE/VCO2 values compared to those without PH or with nfHP.
- A VE/VCO2 slope threshold of ≥42 independently predicted 5-year mortality in HP patients (HR 5.49).
Conclusions:
- In HP patients, increased VE/VCO2 is associated with pulmonary fibrosis, PH, reduced DLCO, and higher mortality risk.
- The VE/VCO2 slope may serve as a practical prognostic marker for risk stratification in HP.
- A VE/VCO2 slope threshold of 42 demonstrates prognostic utility for survival in HP.
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