Aplicação da Teoria dos Conjuntos para o diagnóstico de asma não controlada em crianças

Abstract

The evaluation of asthma control can be performed through a questionnaire such as childhood Asthma Control Test (c-ACT). Spirometry is also a useful tool for assessing the severity of asthma. Indices such as forced expiratory volume in the 1st second (FEV1) and FEV1 ratio by forced vital capacity (FEV1 / FVC) are considered to be more relevant for dimensioning severity than for following asthmatic patients. The hypothesis we developed is that they are also important for assessing asthma control, such as the c-ACT questionnaire. Objective: To identify uncontrolled and controlled asthmatic patients in the pediatric age range from 7 to 11 year-old using the c-ACT, FEV1 and FEV1 / FVC questionnaire. Method: transversal and multicentric work in children with asthma. On the same day of outpatient care, c-ACT was applied, and spirometry was performed. Three parameters were considered to indicate non-asthma control: c-ACT <19, FEV1 <80% and FEV1 / FVC <90%. The c-ACT was the non-control reference in the study. Specificity, negative predictive value (NPV), positive predictive value (PPV), ROC curve, Altman-Bland test and linear correlation and Kappa concordance index were performed using the set theorem. Afterwards, it evaluated the association of two parameters and compared with other associations. Next, a diagnostic point value of the best association of the two parameters was developed and compared with c-ACT. Results: 105 children participated, of which 100 completed all the steps. There were 48 women and 52 men. There was no significant variation of any variable between the male and female groups (p> 0.05). The respective results of c-ACT, FEV1 and FEV1 / FVC were for: sensitivity 55%, 89%, 90%; specificity 76%, 90% and 86.5%; Kappa c-ACT with FEV1 0.014 and Kappa c-ACT with FEV1 / FVC -0.010. After that it was identified that the best association of two variables was c-ACT with FEV1 with sensitivity of 86.21%, specificity, PPV 100% and NPV 84%. We performed the exploratory analysis and the ROC curve that identified the best diagnostic point for the sum of c-ACT and FEV1%, which was <86. This value was compared with c-ACT and obtained a sensitivity of 100% specificity 97.50% and 100% NPV. Conclusion: The c-ACT is a practical instrument that assists in the diagnosis of uncontrolled asthma, but in this population studied it presented low sensitivity and specificity. Almost half of the children are not identified with asthma not controlled by c-ACT. For diagnosis to improve, FEV1% should be associated with c-ACT to identify non-asthma control.