Abstract
Introduction: COPD is the fourth leading cause of death worldwide. FEV1 is predictive of COPD mortality. The IC/TLC is a measure of static lung hyperinflation.
Aims: Analysis of a pulmonary function (PF) database evaluating the influence of FEV1, DLCO, IC/TLC and other variables on survival.
Design: Retrospective analysis of PF data base (31 year). 984 PF's with a reduced FEV1/FVC, increased TLC and reduced DLCO were analyzed. The date of initial PF test was used as the initiation of the survival analysis. 596 subjects had dates of death. Kaplan-Meier survival plots, in addition to Cox analysis was performed to evaluate the relationship of age, FEV1 (GOLD stage), DLCO and IC/TLC ratio on survival, in addition multivariate analyses was performed assessing the effects of age, FEV1, gender, DLCO and BMI with the IC/TLC ratio.
Results: Cox analysis for the risk of death, revealed that a reduced IC/TLC ratio (≤ 25%) [HR 1.69, p<0.0001]; low DLCO (<22% predicted) [HR 1.28, p0.043); increased age [HR 1.035 for 5 year increase, p <0.0001] predicted death. Female gender [HR 0.692, p0.692) and increased FEV1 (mild vs moderate) is predictive of survival [HR 0.69, p 0.0089]. Multivariate analysis revealed that age, gender, and IC/TLC (absolute ratio) remained the only statistically significant independent predictors of survival (HR= 1.04, 95% CI: 1.03-1.04; HR 0.69, 95% CI: 0.60-0.83; HR 1.69, 95% CI: 1.34-2.13, respectively).
Conclusion: Analysis of a PF database reveals statistically significant associations of a number of measured and demographic variables with survival. IC/TLC ratio > 25%, DLCO ≥ 22%, Mild FEV1, Female gender, and BMI >25 is associated with survival.
- © 2011 ERS