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Cabral ALB, Sousa AW, Mendes FAR, Carvalho CRF

inflammation, and a higher number of exacerbations. These findings are supported by a previous study demonstrating that patients presenting multiple allergy sensitizations also had a higher level of severity (moderate to severe asthma), a greater proportion of asthma exacerbations, and a significantly greater proportion of inflammatory markers.(8) In our study, the discriminant analysis that used asthma severity as the dependent variable exhibited poor accuracy and predicted only 31% of the case allocations correctly. Moreover, only the FEV1/FVC ratio and the response to bronchodilators were significantly different among the groups. Health care utilization and fixed airway obstruction were not distinguishing features of asthma severity. Similarly to other studies involving children(6-8) or adults,(2-4) the asthma phenotypes did not correspond to the levels of asthma severity proposed by the GINA guidelines. (9) Moreover, asthma exacerbations and different levels of asthma severity were identified in all of the clusters, a finding that corroborates the study by Fitzpatrick et al.(6) Despite few asthma symptoms and normal lung function, children with asthma also had severe exacerbations. For example, even children and adolescents with mild asthma reported ICU admissions. These findings might have occurred because of the poor socioeconomic conditions in our population; sometimes it is difficult for them to receive proper medical treatment during their infrequent asthma

exacerbations, which might worsen their respiratory status and lead them to an ICU. The degree of pulmonary function impairment in children and adolescents is significantly lower than that previously observed in adults. Although fixed airway obstruction was more frequently found in the patients in cluster 3, it was also identified in those in the other two clusters (13% of the subjects). Therefore, spirometry alone is not a good parameter to determine asthma severity, and the use of spirometry for the management of childhood asthma seems not to improve, by itself, the quality of life of the patients.(19) Most patients (87%) had no fixed airway obstruction, and this fact may present a window of opportunity for proper treatment. In our population, we did not identify an association between obesity and asthma severity, as previously reported in adults.(20) In summary, childhood asthma is characterized by the presence of atopy, a high rate of exacerbations, and fairly preserved lung function. We identified various similarities with the previous clusters that had been described in children and adolescents, and this indicates that this approach has good generalizability. Our study might contribute to a better understanding of asthma phenotypes due to the lack of studies investigating asthma phenotypes in low-income children and adolescents.

REFERENCES 1. Reddel HK, Bateman ED, Becker A, Boulet LP, Cruz AA, Drazen JM, et al. A summary of the new GINA strategy: a roadmap to asthma control. Eur Respir J. 2015;46(3):622-39. http://dx.doi. org/10.1183/13993003.00853-2015 2. Moore WC, Meyers DA, Wenzel SE, Teague WG, Li H, Li X, et al. Identification of asthma phenotypes using cluster analysis in the Severe Asthma Research Program. Am J Respir Crit Care Med. 2010;181(4):315-23. http://dx.doi.org/10.1164/rccm.2009060896OC 3. Haldar P, Pavord ID, Shaw DE, Berry MA, Thomas M, Brightling CE, et al. Cluster analysis and clinical asthma phenotypes. Am J Respir Crit Care Med. 2008;178(3):218-24. http://dx.doi.org/10.1164/ rccm.200711-1754OC 4. Weatherall M, Travers J, Shirtcliffe PM, Marsh SE, Williams MV, Nowitz MR, et al. Distinct clinical phenotypes of airways disease defined by cluster analysis. Eur Respir J. 2009;34(4):812-8. http:// dx.doi.org/10.1183/09031936.00174408 5. Chang TS, Lemanske RF Jr, Mauger DT, Fitzpatrick AM, Sorkness CA, Szefler SJ, et al. Childhood asthma clusters and response to therapy in clinical trials. J Allergy Clin Immunol. 2014;133(2):363-9. http://dx.doi.org/10.1016/j.jaci.2013.09.002 6. Fitzpatrick AM, Teague WG, Meyers DA, Peters SP, Li X, Li H, et al. Heterogeneity of severe asthma in childhood: confirmation by cluster analysis of children in the National Institutes of Health/ National Heart, Lung, and Blood Institute Severe Asthma Research Program. J Allergy Clin Immunol. 2011;127(2):382-389.e1-13. 7. Howrylak JA, Fuhlbrigge AL, Strunk RC, Zeiger RS, Weiss ST, Raby BA; et al. Classification of childhood asthma phenotypes and longterm clinical responses to inhaled anti-inflammatory medications. J Allergy Clin Immunol. 2014;133(5):1289-300, 1300.e1-12. 8. Just J, Saint-Pierre P, Gouvis-Echraghi R, Laoudi Y, Roufai L, Momas I, et al. Childhood allergic asthma is not a single phenotype. J Pediatr. 2014;164(4):815-20. http://dx.doi.org/10.1016/j. jpeds.2013.11.037

9. Boulet LP, FitzGerald JM, Reddel HK. The revised 2014 GINA strategy report: opportunities for change. Curr Opin Pulm Med. 2015;21(1):1-7. http://dx.doi.org/10.1097/MCP.0000000000000125 10. Li D, German D, Lulla S, Thomas RG, Wilson SR. Prospective study of hospitalization for asthma. A preliminary risk factor model. Am J Respir Crit Care Med. 1995;151(3 Pt 1):647-55. http://dx.doi. org/10.1164/ajrccm/151.3_Pt_1.647 11. Proceedings of the ATS workshop on refractory asthma: current understanding, recommendations, and unanswered questions. American Thoracic Society. Am J Respir Crit Care Med. 2000;162(6):2341-51. http://dx.doi.org/10.1164/ ajrccm.162.6.ats9-00 12. Lang AM, Konradsen J, Carlsen KH, Sachs-Olsen C, Mowinckel P, Hedlin G, et al. Identifying problematic severe asthma in the individual child--does lung function matter? Acta Paediatr. 2010;99(3):404-10. http://dx.doi.org/10.1111/j.1651-2227.2009.01625.x 13. Sakagami T, Hasegawa T, Koya T, Furukawa T, Kawakami H, Kimura Y, et al. Cluster analysis identifies characteristic phenotypes of asthma with accelerated lung function decline. J Asthma. 2014;51(2):113-8. http://dx.doi.org/10.3109/02770903.2013.8522 01 14. Quanjer PH, Stanojevic S, Cole TJ, Baur X, Hall GL, Culver BH, et al. Multi-ethnic reference values for spirometry for the 3-95-yr age range: the global lung function 2012 equations. Eur Respir J. 2012;40(6):1324-43. http://dx.doi.org/10.1183/09031936.00080312 15. Pellegrino R, Viegi G, Brusasco V, Crapo RO, Burgos F, Casaburi R, et al. Interpretative strategies for lung function tests. Eur Respir J. 2005;26(5):948-68. http://dx.doi.org/10.1183/09031936.05.0003 5205 16. Hair JF Jr, Black WC, Babin BJ, Anderson RE, Tatham RL. Multivariate Data Analysis. 6th ed. Upper Saddle River (NJ): Pearson/Prentice Hall; 2006. p. 221-302. 17. Garcia-Aymerich J, Benet M, Saeys Y, Pinart M, Basaga-a X, Smit HA, et al. Phenotyping asthma, rhinitis and eczema in MeDALL J Bras Pneumol. 2017;43(1):44-50

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Profile for Jornal Brasileiro Pneumologia

JBP - Volume 43, number 1, January-February 2017  

The Brazilian Journal of Pulmonology (JBP) publishes scientific articles that contribute to the improvement of knowledge in the field of the...

JBP - Volume 43, number 1, January-February 2017  

The Brazilian Journal of Pulmonology (JBP) publishes scientific articles that contribute to the improvement of knowledge in the field of the...

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