Should we monitor peak expiratory flow rates or record symptoms with a simple diary in the management of asthma?

Background: Various means of monitoring asthma severity have been proposed to reduce morbidity and mortality rates. We compared two means of assessing asthma flare-ups: monitoring peak expiratory flow rate (PEFR) and keeping a symptom diary. Methods: This was a crossover randomized study. After a 2-week baseline period during which spirometry and PC 20 methacholine were assessed, subjects were asked to record either PEFRs or to keep a symptom diary morning and evening for 6 months; a second baseline assessment separated the two periods. Subjects were asked to contact the study coordinator if the following occurred: (1) in the period of PEFR monitoring, daily fluctuations in PEFR were >20% or the absolute value fell to