Objective: To correlate forced expiratory volume in 1 second (VEF(1)) and peak expiratory flow (PEF) with clinical parameters in children with moderate and severe asthma.
Methods: This was a non-concurrent cohort study, carried out at a pediatric pneumology clinic, in Belo Horizonte, MG, Brazil, between March and October 2002. The study enrolled children aged 5 to 16 years, with persistent asthma, being treated with a minimum of 500 mcg/day beclomethasone, and with symptoms under control for at least 3 months. Seventy-five patients (96.1%) were selected by simple randomization and monitored for 3 months, via a clinical severity scale and pulmonary function tests (PEF and VEF(1)). Results were analyzed using Pearson's coefficient.
Results: Correlations between absolute and percentage PEF figures and clinical severity score were negative and very close to zero, signifying a weak correlation with no statistical significance. The same relationship was observed between VEF(1) and clinical severity score. The correlation between VEF(1) and PEF had a positive value with statistical significance (p = 0.000).
Conclusions: Since the best parameter for evaluating airway obstruction is VEF(1), the finding that there is a positive correlation between this measure and absolute PEF reinforces the importance of its use and allows for the recommendation that PEF be measured as part of the management of asthmatic children, particularly in severe cases.