Identification of COPD Patients at High Risk for Lung Cancer Mortality Using the COPD-LUCSS-DLCO.

Abstract

The COPD-Lung Cancer Screening Score (COPD-LUCSS) is a tool designed to help identify patients with COPD with the highest risk of developing lung cancer (LC). The COPD-LUCSS includes the determination of radiological emphysema, a potential limitation for its implementation in clinical practice. The diffusing capacity for carbon monoxide (DLCO) is a surrogate marker of emphysema and correlates well with CT-determined emphysema. To explore the use of the COPD-LUCSS using the DLCO instead of radiological emphysema, as a tool to identify patients with COPD at higher risk of LC death. The Body Mass Index, Airflow Obstruction, Dyspnea, Exercise Performance international cohort database was analyzed. By logistic regression analysis, we confirmed that the other parameters included in the COPD-LUCSS (age > 60, pack-years > 60, BMI < 25) were independently associated with LC death. We selected the best cutoff value for DLCO that independently predicted LC death. We then integrated the new COPD-LUCSS-DLCO assigning points to each parameter according to its hazard ratio value in the Cox regression model. The score ranges from 0 to 8 points. By regression analysis, age > 60, BMI <25 kg/m(2), pack-year history > 60, and DLCO < 60% were independently associated with LC diagnosis. Two COPD-LUCSS-DLCO risk categories were identified: low risk (scores 0-3) and high risk (scores 3.5-8). In comparison to patients at low risk, risk of death from LC increased 2.4-fold (95% CI, 2.0-2.7) in the high-risk category. The COPD-LUCSS using DLCO instead of CT-determined emphysema is a useful tool to identify patients with COPD at risk of LC death and may help in its implementation in clinical practice.