Lack of correlation between clinical patterns of asthma and airway obstruction

dTo evaluate the relationship between the classification of asthma and obst ruction of airways, we have studied 100 children suffering from allergic as thma: 65 mates and 35 females, aged 4.2-16.3 years (mean, 7.6 +/- 2.8 years ), who were evaluated at least 1 month after the last attack of airway obst ruction. We analyzed personal history of all children with special referenc e to number of attacks of airway obstruction in the lost year, severity, an d presence of respiratory symptoms in the last month. The children studied have been classified in three groups according to the International Pediatr ic Respiratory Allergy, Forum (IPRAF) '98 method (Third International Pedia tric Consensus Statement on the management of childhood asthma). All childr en underwent the assessment of their respiratory function by means of analy sis of the flow/volume loops with measurement of the obstruction indices (f orced expiratory volume in 1 second [FEVI1], peak expiratory flow [PEF], an d maximal midexpiratory flow [MMEF]). The efficacy of the aforementioned me thod has been evaluated by analyzing the number of the subjects who showed indices of airway obstruction not in agreement with. the group assigned. Ei ghty-five of the children studied were diagnosed with infrequent episodic a sthma (IEA), 14 children were diagnosed with frequent episodic asthma (FEA) , and 1 child was diagnosed with persistent asthma (PA). Thirty-six of 100 children showed obstruction indices not in agreement with the asthma group: in particular, 24 of 85 children with IEA had FEV1 < 80%, 11 children vith FEA had FEV1 > 80%, and 1 child vith PA had FEV1 > 80%. The high percentag e of discordance between clinical classification and obstruction index in t he subjects vith IEA can be caused by the persistence of abnormalities of t he respiratory function without clinical symptoms. The presence of a normal obstruction index in the subjects with FEA can be explained by the pharmac ologic therapies. These data suggest the usefulness of a careful evaluation of the respiratory function associated with a clinical assessment to carry out a more appropriate therapy.