FEV1:FVC Thresholds for Defining Chronic Obstructive Pulmonary Disease

To the Editor The discriminative accuracy of various FEV1:FVC fixed thresholds for predicting COPD-related hospitalization and mortality was evaluated using data from 4 US general population –based cohorts with a median follow-up of 15 years. The authors defined the optimal fixed FEV1:FVC threshold by the best discrimination for COPD-related events as indexed using the Harrell C statistic from unadjusted Cox proportional hazards models. The authors further determined the significance of differences in C statistics with respect to FEV1:FVC less than 0.70 and less than the LLN thresholds using a nonparametric approach, and they concluded that their results support the use of an FEV1:FVC less than 0.70 to identify individuals at risk of clinically significant COPD. We have some con cerns regarding the statistical methods used.
Source: JAMA - Category: General Medicine Source Type: research