Rendimiento clínico de espirometría y oscilometría respiratoria para predecir crisis graves en escolares con asma / Clinical performance of spirometry and respiratory oscillometry for prediction of severe exacerbations in schoolchildren with asthma

Objetivo: Determinar el rendimiento de espirometría y oscilometría respiratoria (RO) para predecir crisis de asma graves (CAG) en niños. Métodos: En un estudio prospectivo, 148 niños (6-14 años) con asma realizaron RO, espirometría y prueba broncodilatadora. Se clasificaron en fenotipos de atrapamiento aéreo (ATA), limitación del flujo aéreo (LFA) y normal, según la espirometría y prueba broncodilatadora. A las 12 semanas fueron revalorados respecto a aparición de CAG. Se analizó el rendimiento de los parámetros de RO, espirometría y fenotipos ATA/LFA para predecir la aparición de CAG con cocientes de probabilidad positivos y negativos (LR+/LR−), área bajo la curva de curvas ROC y análisis multivariante ajustado por posibles factores de confusión. Resultados: Un 7,4% tuvo CAG en el seguimiento, con diferencias según fenotipo (Normal 2,4%; LFA 17,9%; ATA 22,2%; p=0,005). La mejor área bajo la curva fue del flujo espiratorio forzado 25-75% (FEF25-75): 0,787; intervalo de confianza 95%: 0,600-0,973. También tuvieron áreas bajo la curva significativas el área de reactancia (AX), el volumen espiratorio forzado en el primer segundo (FEV1), el cambio post-broncodilatador en capacidad vital forzada (FVC), y FEV1/FVC. Todas las variables tenían una baja sensibilidad para predecir CAG. La mejor especificidad correspondía al fenotipo ATA: 93,8% (intervalo de confianza del 95% 87,9-97,0), pero solo FEF25-75 tenía tanto LR+ como LR− significativos. En el análisis multivariante, solo algunos parámetros de espirometría fueron significativos para predecir CAG (fenotipo ATA, FEF25-75 y FEV1/FVC). Conclusiones: La espirometría tiene un rendimiento superior a la RO para predecir CAG a medio plazo en escolares con asma. (AU)

Objective: To determine the performance of spirometry and respiratory oscillometry (RO) in the prediction of severe asthma exacerbations (SAEs) in children. Methods: In a prospective study, 148 children (age 6–14 years) with asthma were assessed with RO, spirometry and a bronchodilator test. Based on the findings of spirometry and the bronchodilator test, they were classified into 3 phenotypes: air trapping (AT), airflow limitation (AL) and normal. Twelve weeks later, they were re-evaluated in relation to the occurrence of SAEs. We analysed the performance of RO, spirometry and AT/AL phenotypes for prediction of SAEs by means of positive and negative likelihood ratios (LR+/LR–), ROC curves with the corresponding areas under the curve and a multivariate analysis adjusted for potential confounders. Results: During the followup, 7.4% of patients had SAEs, and there were differences between phenotypes (normal, 2.4%; AL, 17.9%; AT, 22.2%, P=.005). The best area under the curve corresponded to the forced expiratory flow between 25% and 75% of vital capacity (FEF25–75): 0.787; 95% confidence interval, 0.600-0.973. Other significant areas under the curve were those for the reactance area (AX), forced expiratory volume in the first second (FEV1), the post- bronchodilator change in forced vital capacity (FVC), and the FEV1/FVC ratio. All of the variables had a low sensitivity for prediction of SAEs. The AT phenotype had the best specificity (93.8%; 95% confidence interval, 87.9-97.0), but LR+ and LR– were both significant only for the FEF25–75. In the multivariate analysis, only some spirometry parameters were significative for prediction of SAEs (AT phenotype, FEF25–75 and FEV1/FVC). Conclusions: Spirometry performed better than RO for prediction of SAEs in the medium term in schoolchildren with asthma. (AU)

Clinical performance of spirometry and respiratory oscillometry for prediction of severe exacerbations in schoolchildren with asthma.

OBJECTIVE: To determine the performance of spirometry and respiratory oscillometry (RO) in the prediction of severe asthma exacerbations (SAEs) in children. METHODS: In a prospective study, 148 children (age 6-14 years) with asthma were assessed with RO, spirometry and a bronchodilator (BD) test. Based on the findings of spirometry and the BD test, they were classified into three phenotypes: air trapping (AT), airflow limitation (AFL) and normal. Twelve weeks later, they were re-evaluated in relation to the occurrence of SAEs. We analysed the performance of RO, spirometry and AT/AFL phenotypes for prediction of SAEs by means of positive and negative likelihood ratios, ROC curves with the corresponding areas under the curve (AUCs) and a multivariate analysis adjusted for potential confounders. RESULTS: During the follow-up, 7.4% of patients had SAEs, and there were differences between phenotypes (normal, 2.4%; AFL, 17.9%; AT, 22.2%, P = .005). The best AUC corresponded to the forced expiratory flow between 25% and 75% of vital capacity (FEF25-75): 0.787; 95% confidence interval, 0.600-0.973. Other significant AUCs were those for the reactance area (AX), forced expiratory volume in the first second (FEV1), the post-BD change in forced vital capacity (FVC), and the FEV1/FVC ratio. All of the variables had a low sensitivity for prediction of SAEs. The AT phenotype had the best specificity (93.8%; 95% CI, 87.9-97.0), but the positive and negative likelihood ratios were both significant only for the FEF25-75. In the multivariate analysis, only some spirometry parameters were significative for prediction of SAEs (AT phenotype, FEF25-75 and FEV1/FVC). CONCLUSIONS: Spirometry performed better than RO for prediction of SAEs in the medium term in schoolchildren with asthma.

Spirometry and respiratory oscillometry: Feasibility and concordance in schoolchildren with asthma.

OBJECTIVE: The purpose of this study was to describe the feasibility of respiratory oscillometry (RO) in schoolchildren with asthma, and the concordance of its results with those of spirometry, to determine its clinical usefulness. METHODS: RO and spirometry were performed in 154 children (6 to 14-year-old) with asthma, following strict quality criteria for the tests. Their feasibility (probability of valid test, time of execution, number of maneuvers needed to achieve a valid test, and perceived difficulty) was compared. The factors that influence feasibility were analyzed with multivariate methods. FEV1, FEV1/FVC, FVC and FEF25-75 for spirometry, and R5, AX and R5-19 for RO, were converted into z-scores and their concordance was investigated through intraclass correlation coefficients (ICC) and kappa indices for normal/abnormal values. RESULTS: There were no differences in the probability of obtaining a valid RO or spirometry (83.1% vs. 81.8%, p = 0.868). RO required a lower number of maneuvers [mean (SD) 4.2 (1.8) versus 6.0 (1.6), p < 0.001] and less execution time [5.1 (2.7) versus 7.6 (2.4) minutes, p < 0.001], and patients considered it less difficult. Age increased the probability of obtaining valid RO and spirometry. The concordance of results between RO and spirometry was low, and only between zFEV1 and zAX could it be considered moderate (ICC = 0.412, kappa = 0.427). CONCLUSION: RO and spirometry are feasible in children with asthma. RO has some practical advantages, but the concordance of its results with spirometry is low.