HOW MANY ASTHMATIC PATIENTS HAVE ASTHMA?

Abstract

To the Editor: The article by Castro-Rodriguez et al1 describes the characteristics of 237 children (4–14 years old) with an asthma diagnosis in a developing country who were followed up at a tertiary care institution. The main inclusion criterion was asthma. All the children underwent spirometry (before and after bronchodilator therapy) and exercise challenge testing. A positive bronchodilator response was defined as an improvement in forced expiratory volume in 1 second of more than 15%. Based on allergen skin prick test results, children were divided into 2 groups: atopic asthma and nonatopic asthma. The clinical, functional, and epidemiologic characteristics of both groups were described. However, a few points should have been considered before its publication. First, it is well known that not all children who wheeze have asthma. Transient early wheezers are not considered to have asthma. They wheeze at the age of 3 years but not at the age of 6 years, and up to 15% of them may wheeze at the age of 16 years.2,3 They are not atopic. Second, the prevalence of atopy increases with age as asthma becomes a likely diagnosis. In the Tucson cohort the prevalence of atopy in wheezers (persistent and late) by means of skin prick testing performed at the age of 6 years was 53.4% and at the age of 16 years was 82.1%.2,3 Third, and as expected, the prevalence of atopy is higher in children who have asthma. In the Characterizing the Response to a Leukotriene Receptor Antagonist and an Inhaled Corticosteroid trial4 the prevalence of atopy in asthmatic children was 78%. All the asthmatic patients had asthma; 3% had bronchodilator reversibility, 33% had methacholine responsiveness, and the remaining 64% had both.4 Therefore, it is impossible to conclude that children in the study by Castro-Rodriguez et al1 have asthma, first because they did not present their data on bronchodilator responses and second because they included patients in a wide age range (4–14 years old). Asthma is often overdiagnosed, and this study proves it.5 Mixed populations of wheezers are presented as asthmatic patients, as if everything learned during the past 20 years had vanished.2,3 It is possible that clinical guidelines implementation may be responsible for asthma overdiagnosis.5,6 However, researchers should answer the title question, “How many asthmatic patients have asthma?” Policymakers, health payers, patients, and physicians want to know the answer but do not have the information that these researchers have withheld. JOSE E. GEREDA, MD Allergy and Immunology Clinica Ricardo Palma Lima, Peru