FVC/DLCO identifies pulmonary hypertension and predicts 5-year all-cause mortality in patients with COPD

Abstract Background Pulmonary hypertension (PH) is a common complication of chronic obstructive pulmonary disease (COPD). However, it is unknown whether the ratio of forced vital capacity (FVC) to diffusing lung capacity for carbon monoxide (DLCO) can identify PH in the patients with COPD and predict its prognosis. Methods The study population I included 937 COPD patients who were admitted to inpatient treatments from 2010 to 2017, and finally 750 patients were available to follow-up the 5-year all-cause mortality (study population II). Clinical characteristics of the study population were recorded. Results COPD patients with PH had a higher FVC/DLCO value compared with the patients without PH. The threshold for FVC/DLCO to identify PH in COPD patients was 0.44 l/mmol/min/kPa. Multivariate logistic regression analysis showed that FVC/DLCO was a significant predictor for PH in the patients with COPD. The study population II showed that the 5-year all-cause mortality of COPD patients was significantly higher in combined with PH group than without PH group. Compared with the survivor group, FVC/DLCO value was significantly increased in non-survivor group. The threshold for FVC/DLCO to predict 5-year all-cause mortality was 0.41 l/mmol/min/kPa. Kaplan–Meier survival curves showed that 5-year cumulative survival rate for COPD patients were significantly decreased when the value of FVC/DLCO was ≥ 0.41 l/mmol/min/kPa. Multivariate cox regression analysis showed that FVC/DLCO was an independent prognostic factor for 5-year all-cause mortality in COPD patients. Conclusion FVC/DLCO could identify PH in the patients with COPD and was an independent predictor for 5-year all-cause mortality of COPD.