Respiratory symptoms in asthma: The view through a wide-angle lens

ary analysis of data collected in the context of a clinical trial of preschool-aged children with asthma and examined wheeze, cough, and difficulty breathing as predictors of exacerbations. The authors found that any combination of symptoms that included cough was a more sensitive predictor of an exacerbation the following day than combinations of symptoms including either wheezeordifficultybreathingandthathalfoftheexacerbations were not preceded by parent-reported wheeze. The authors conclude that the more narrowly focused approach of relying on wheezeasthesolesymptominformingtreatmentcouldleadtodelayed treatment or undertreatment of exacerbations, which could be avoided by taking a broader view, and relying on a global assessment of ‘‘significant troublesome lung symptoms’’ instead. On the one hand, this finding reflects standard clinical care as described in both US 3 and international 4 asthma guidelines, which incorporate evaluation of nonwheezing symptoms as an integral part of the assessment of asthma control. Validated asthma symptom and control tools also include assessment of nonwheezing asthma symptoms. 5,6 On the other hand, clinical practice guidelines focus less on identification of an imminent exacerbation, and this study’s findings suggest that educating parents and clinicians specifically that ‘‘significant troublesome lung symptoms,’’ even when wheeze is not present, are a potential harbinger of an exacerbation could result in earlier intervention and potential reduction of morbidity. This hypothesis, that intervention at the onset of significant lower respiratory tract symptoms could reduce morbidity, is ripe for testing in a clinical trial. It is important to note that although wheeze was a significantly less sensitive indicator of an impending exacerbation than nonwheezing symptoms, wheeze was a more specific indicator of an impending exacerbation, highlighting the fact that, despite its well-described limitations, wheeze is still an important asthma symptom and should not be dismissed by a clinician or tossed aside in the development of practice guidelines or asthma assessment tools, particularly in populations in which wheeze is a common term. Clinical experience would suggest that the authors’ observations reflect the natural history of asthma exacerbations, which typically begin with milder nonwheezing symptoms and then progress to frank wheezing. Consistent with this observation, others have reported that nonwheezing symptoms are the most reliable predictor of subsequent wheeze in young children, with significant cough having a 74% positive predictive value for subsequent wheezing. 7 Furthermore, parents might not attribute nonwheezing symptoms to asthma. When parents report that their asthmatic child has a cough, they often add that ‘‘it’s because he has a cold,’’ not recognizing that the cough is likely attributable to their child’s asthma and a potential reason to intervene. Several questions remain. For example, are nonwheezing symptoms a sufficiently accurate predictor of an exacerbation that their occurrence should trigger a step-up in therapy? And because nonwheezing symptoms most strongly predicted an exacerbation occurring the following day, is this 1-day lead time a sufficient amount of time for an intervention to avert an