Patients with chronic obstructive pulmonary disease (COPD) who had a low diffusing capacity of the lung for carbon monoxide (DLCO) were at an increased risk for negative health outcomes, according to the results of a recent study published in the journal BMC Pulmonary Medicine.

Researchers retrospectively reviewed and analyzed outcomes data from patients with acute exacerbations of COPD for potential prognostic markers. Of particular interest were the effects of DLCO and forced expiratory volume in 1 second (FEV1). Patients were categorized as either normal or impaired for each measurement. Outcomes included in-hospital mortality, need for mechanical ventilation, and need for care in an intensive care unit (ICU).

Among the 342 patients with acute exacerbation of COPD, 115 were determined to have impaired DLCO, and 169 had impaired FEV1. When outcomes were examined and compared between typical and impaired groups, impaired DLCO was associated with mortality (odds ratio [OR], 4.408; 95% CI, 1.070-18.167; P =.040), need for mechanical ventilation (OR, 2.855; 95% CI, 1.216-6.704; P =.016), and need for ICU care (OR, 2.685; 95% CI, 1.290-5.590; P =.008).

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When using FEV1 classification, there was no statistically significant difference in mortality (P =.075). Both impaired FEV1 and DLCO were negatively associated with length of hospital stay. In the receiver operating characteristic (ROC) analysis, the area under the curve (AUC) of DLCO was >0.68 for all prognostic factors while the AUC of FEV1 was <0.68.

“DLCO was likely to be as good as or better as a prognostic marker than FEV1 in severe [acute exacerbation of] COPD,” the study authors wrote. “Accurate classification using DLCO may help to treat severe [acute exacerbation of] COPD patients.”


Choi J, Sim JK, Oh JY, et al. Prognostic marker for severe acute exacerbation of chronic obstructive pulmonary disease: analysis of diffusing capacity of the lung for carbon monoxide (DLCO) and forced expiratory volume in one second (FEV1). BMC Pulm Med. Published online May 6, 2021. doi:10.1186/s12890-021-01519-1