Obstructive lung disease [chapter]

2002 Cardiopulmonary Critical Care  
The present cross-sectional, population-based study was designed to evaluate the performance of the FEV 1 /FEV 6 ratio for the detection of airway-obstructed subjects compared to the FEV 1 /FVC <0.70 fixed ratio test, as well as the lower limit of normality (LLN) for 1000 subjects ≥40 years of age in the metropolitan area of São Paulo, SP, Brazil. After the exclusion of 37 (3.7%) spirometries, a total of 963 pre-bronchodilator (BD) and 918 post-BD curves were constructed. The majority of the
more » ... majority of the post-BD curves (93.1%) were of very good quality and achieved grade A (762 curves) or B (93 curves). The FEV 1 /FEV 6 and FEV 1 /FVC ratios were highly correlated (r 2 = 0.92, P < 0.000). Two receiver operator characteristic curves were constructed in order to express the imbalance between the sensitivity and specificity of the FEV 1 /FEV 6 ratio compared to two FEV 1 /FVC cut-off points for airway obstruction: equal to 70 (area under the curve = 0.98, P < 0.0001) and the LLN (area under the curve = 0.97, P < 0.0001), in the post-BD curves. According to an FEV 1 /FVC <0.70, the cut-off point for the FEV 1 /FEV 6 ratio with the highest sum for sensitivity and specificity was 0.75. The FEV 1 /FEV 6 ratio can be considered to be a good alternative to the FEV 1 /FVC ratio for the diagnosis of airway obstruction, both using a fixed cut-off point or below the LLN as reference. The FEV 1 /FEV 6 ratio has the additional advantage of being an easier maneuver for the subjects and for the lung function technicians, providing a higher reproducibility than traditional spirometry maneuvers. Correspondence J.R. Jardim Disciplina de Pneumologia EPM, Unifesp Rua Botucatu, 740, 3º andar 04023-062 São Paulo, SP Brasil
doi:10.3109/9780203427675-18 fatcat:lon7qs75xbaavba62craelbp3a