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

Abstract 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 20 or both. Forty subjects completed a 6-month symptom diary or PEFR recording period respectively, and 20 completed both. Results: A total of 31 exacerbations were reported in 28 different subjects; three subjects had two flare-ups. Thirteen of 19 (69%) flare-ups were confirmed during the symptom diary period and 9 of 12 (75%) during PEFR monitoring. Nocturnal awakenings and morning falls in PEFR ≥20% were the most frequent occurrences. Conclusions: We conclude that a simple symptom diary may be as useful as serial PEFR monitoring in documenting asthmatic flare-ups.