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

BackgroundPulmonary 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 (D-LCO) can identify PH in the patients with COPD and predict its prognosis.MethodsThe 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.ResultsCOPD patients with PH had a higher FVC/D-LCO value compared with the patients without PH. The threshold for FVC/D-LCO to identify PH in COPD patients was 0.44 l/mmol/min/kPa. Multivariate logistic regression analysis showed that FVC/D-LCO 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/D-LCO value was significantly increased in non-survivor group. The threshold for FVC/D-LCO 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/D-LCO was >= 0.41 l/mmol/min/kPa. Multivariate cox regression analysis showed that FVC/D-LCO was an independent prognostic factor for 5-year all-cause mortality in COPD patients.ConclusionFVC/D-LCO could identify PH in the patients with COPD and was an independent predictor for 5-year all-cause mortality of COPD.