Measures of asthma severity recorded by patients

Twenty-nine children with asthma made daily recordings of the severity of their asthma for 8 months. Each child recorded four measures of severity: a medication usage score, a morning peak expiratory flow rate (PEFR), an evening PEFR, and a subjective rating of overall severity. We determined the relationships between the four measures. Except for the morning and evening PEFRs, the relationships between the measures were weak; the PEFR measures were highly related to one another. The relationship between PEFR scores and medication usage scores increased following biofeedback relaxation training.