Relationship between handheld and clinic-based spirometry measurements in asthma patients receiving beclomethasone.

INTRODUCTION

Handheld spirometers for home use by patients allow longitudinal spirometry data to be collected daily and may overcome some of the limitations of in-clinic spirometry (long intervals between measurements, results can be affected by site-based coaching and patient's asthma status during a given visit).

OBJECTIVES

To determine the relationship between spirometry values measured by clinic-based and handheld spirometers during a clinical trial.

METHODS

A post hoc correlation analysis of data from a 6-week phase 3 study of beclomethasone dipropionate (BDP; delivered by breath-actuated inhaler: BAI) versus placebo in patients aged ≥12 years with persistent asthma. During the study, forced expiratory volume in 1 s (FEV) was assessed by both office-based spirometry at Weeks 2, 4 and 6, and daily by handheld spirometer as a secondary study endpoint.

RESULTS

There was a high correlation between FEV values measured at home and in-clinic (overall correlation coefficient = 0.8393, R = 0.81921, 0.85927, 0.85369 and 0.83734 for BAI 320 μg/day, BAI 640 μg/day, BDP metered dose inhaler 320 μg/day and placebo treatment groups, respectively), with the scatterplot showing an upward trend for all treatment groups. Nearly all patients achieved home FEV values close to clinic FEV values, with very few outliers.

CONCLUSIONS

Clinic-based and handheld spirometry demonstrated comparable treatment effects relative to placebo, suggesting that home spirometry could be used to help patients monitor their asthma severity. Daily measurement of FEV provides more comprehensive data than can be achieved through clinic visits, and may lead to a new approach to clinical trial design.