TY - JOUR
T1 - Diffusing Capacity Is an Independent Predictor of Outcomes in Pulmonary Hypertension Associated With COPD
AU - Balasubramanian, Aparna
AU - Kolb, Todd M.
AU - Damico, Rachel L.
AU - Hassoun, Paul M.
AU - McCormack, Meredith C.
AU - Mathai, Stephen C.
N1 - Funding Information:
FUNDING/SUPPORT: This work was supported by the National Heart Lung and Blood Institute [grant T32 HL007534-36].
Funding Information:
FUNDING/SUPPORT: This work was supported by the National Heart Lung and Blood Institute [grant T32 HL007534-36 ].
Publisher Copyright:
© 2020
PY - 2020/8
Y1 - 2020/8
N2 - Background: Patients with COPD who experience pulmonary hypertension (PH) have worse mortality than those with COPD alone. Predictors of poor outcomes in COPD-PH are not well-described. Diffusing capacity of the lung (DLCO) assesses the integrity of the alveolar-capillary interface and thus may be a useful prognostic tool among those with COPD-PH. Research Question: Using a single center registry, we sought to evaluate DLCO as a predictor of mortality in a cohort of patients with COPD-PH. Study Design and Methods: This retrospective cohort study analyzed 71 COPD-PH patients from the Johns Hopkins Pulmonary Hypertension Registry with right-sided heart catheterization (RHC)-proven PH and pulmonary function testing data within one year of diagnostic RHC. Transplant-free survival was calculated from index RHC. Adjusted transplant-free survival was modelled using Cox proportional hazard methods; age, pulmonary vascular resistance, FEV1, oxygen use, and N-terminal pro-brain natriuretic peptide were included as covariates. Results: Overall unadjusted transplant-free 1-, 3-, and 5-year survivals were 87%, 60%, and 51%, respectively. Survival was associated with reduced DLCO across the observed range of pulmonary artery pressures and pulmonary vascular resistance. Severe DLCO impairment was associated with poorer survival (log-rank χ2 13.07) (P < .001); adjusting for covariates, for every percent predicted decrease in DLCO, mortality rates increased by 4% (hazard ratio, 1.04; 95% CI, 1.01-1.07). Interpretation: Among patients with COPD-PH, severe gas transfer impairment is associated with higher mortality, even with adjustment for airflow obstruction and hemodynamics, which suggests that DLCO may be a useful prognostic marker in this population. Future studies are needed to further investigate the association between DLCO and morbidity and to determine the utility of DLCO as a biomarker for disease risk and severity in COPD-PH.
AB - Background: Patients with COPD who experience pulmonary hypertension (PH) have worse mortality than those with COPD alone. Predictors of poor outcomes in COPD-PH are not well-described. Diffusing capacity of the lung (DLCO) assesses the integrity of the alveolar-capillary interface and thus may be a useful prognostic tool among those with COPD-PH. Research Question: Using a single center registry, we sought to evaluate DLCO as a predictor of mortality in a cohort of patients with COPD-PH. Study Design and Methods: This retrospective cohort study analyzed 71 COPD-PH patients from the Johns Hopkins Pulmonary Hypertension Registry with right-sided heart catheterization (RHC)-proven PH and pulmonary function testing data within one year of diagnostic RHC. Transplant-free survival was calculated from index RHC. Adjusted transplant-free survival was modelled using Cox proportional hazard methods; age, pulmonary vascular resistance, FEV1, oxygen use, and N-terminal pro-brain natriuretic peptide were included as covariates. Results: Overall unadjusted transplant-free 1-, 3-, and 5-year survivals were 87%, 60%, and 51%, respectively. Survival was associated with reduced DLCO across the observed range of pulmonary artery pressures and pulmonary vascular resistance. Severe DLCO impairment was associated with poorer survival (log-rank χ2 13.07) (P < .001); adjusting for covariates, for every percent predicted decrease in DLCO, mortality rates increased by 4% (hazard ratio, 1.04; 95% CI, 1.01-1.07). Interpretation: Among patients with COPD-PH, severe gas transfer impairment is associated with higher mortality, even with adjustment for airflow obstruction and hemodynamics, which suggests that DLCO may be a useful prognostic marker in this population. Future studies are needed to further investigate the association between DLCO and morbidity and to determine the utility of DLCO as a biomarker for disease risk and severity in COPD-PH.
KW - COPD
KW - mortality
KW - pulmonary diffusing capacity
KW - pulmonary gas exchange
KW - pulmonary hypertension
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U2 - 10.1016/j.chest.2020.02.047
DO - 10.1016/j.chest.2020.02.047
M3 - Article
C2 - 32184109
AN - SCOPUS:85087428402
VL - 158
SP - 722
EP - 734
JO - Diseases of the chest
JF - Diseases of the chest
SN - 0012-3692
IS - 2
ER -