ADEQUACY OF CONTROL OF ASTHMA IN A GENERAL-PRACTICE - IS MAXIMUM PEAKEXPIRATORY FLOW-RATE A VALID INDEX OF ASTHMA SEVERITY

Objectives: To evaluate the adequacy of control of asthma in patients attending a general practice; and to examine the validity of peak expi ratory flow rate (PEFR) as an index of asthma severity in the context of general practice. Design: Short-term cohort study using indices der ived from two weeks of peak flow monitoring to evaluate asthma control . Participants: Known and newly diagnosed asthmatics aged six years or more who presented during the study period for any reason. They were enrolled if baseline forced expiratory volume in one second (FEV(1)) i ncreased by 10% or more after the administration of nebulised salbutam ol. Children under the age of 12 years with no initial response to bro nchodilator were included if an exercise test performed on another day was positive. Outcome measures: Peak flow criteria for ''mild asthma' ' in the Asthma Management Plan, 1989 (Med J Aust 1989; 151: 650-653) were used as the initial definition of ''adequate control'' The defini tion of ''adequate control'' was modified to variability less than 20% and a minimum PEFR of 50% or more of mean predicted value. Results: T here was no association between variability and maximum PEFR, but vari ability was strongly correlated with minimum PEFR (R = -0.60; P < 0.00 05). Asthma was adequately controlled in 68% of the participants. Conc lusion: Current guidelines with respect to the peak flow indices used in the classification of the severity of asthma need to be re-evaluate d and probably changed for application in general practice.