A Review of the Role of FEV1 in the COPD Paradigm

Historically, spirometry has been the objective measure used to confirm a symptom-based clinical suspicion of COPD. The third National Health and Nutrition Examination Survey (NHANES III) created a strong rationale for early identification and intervention in COPD by documenting the ability of spirometry to detect mild airflow problems in many asymptomatic smokers. Predicted values for spirometry, however, must be adjusted to account for variations in age, gender, height, ethnicity and race. Many experts agree that NHANES III reference equations are much better suited to COPD practice than most other predicted value standards. However, standards other than NHANES III have been adopted in current medical guidelines; standards that may inappropriately classify younger adults as normal and older adults as abnormal, potentially leading to widespread misdiagnosis and mis-directed therapies in clinical practice. Despite the shortcomings of established diagnostic predicted values, spirometry remains the best available tool for early and accurate diagnosis of COPD in those at risk for the disease, and is also useful in conjunction with other modalities in patients with established disease to determine prognosis and assessing therapeutic benefits. In the clinical trial settings, as well as in day-to-day practice, spirometry results should be combined with other endpoints in order to better reflect overall patient status. This review highlights key medical evidence surrounding both usefulness and limitations of FEV1 in the setting of COPD.