Relation between FEV1 and peak expiratory flow in patients with chronic airflow obstruction

Abstract

We have re-examined the relation between FEV1 and PEF in a cross sectional study of 61 patients undergoing routine lung function testing and we have assessed the effect on the relation of expressing each index as a percentage of the predicted value. This should minimise variability between subjects, other than that due to the severity of airflow obstruction. We have also studied a group of patients undergoing corticosteroid trials in whom sequential values of both FEV1 and PEF were obtained at the same time, and from these we have selected those who showed a definite steroid response, to examine within subject relationships between PEF and FEV1 and to compare these with the relationships in the cross sectional study.