Usefulness of bronchial reactivity analysis in the diagnosis of bronchial asthma in patients with bronchial hyperresponsiveness

Abstract

We examined the usefulness of some bronchial reactivity indices to identify bronchial asthma in patients with airway hyperresponsiveness. Eighty-eight consecutive patients with positive response to histamine bronchial challenge (> or = 20% fall in FEV1) were included in the study. Dose-response curves were characterised by their sensitivity (PD20) and reactivity. Dose-response slope, continuous index of responsiveness (CIR) and bronchial reactivity index (BRI) with respect to baseline and post-diluent baseline values were determined as reactivity indices. The clinical diagnosis remaining in the case history 2 years after the bronchial challenge was considered the definitive diagnosis. Asthmatic patients had higher baseline BRI (12.121+/-0.412 vs. 11.615+/-0.201; P<0.001) and post-diluent baseline BRI (12.054+/-0.368 vs. 11.563+/-0.531; P = 0.003) than other subjects. Area beneath their receiver operating characteristic (ROC) curve was 82.68% (standard error: 0.77) for the baseline BRI and 81.73 (standard error: 0.76). By multiple logistic regression analysis, baseline BRI was the only independent variable identified as a predictor for diagnosis of bronchial asthma (r = 0.387, P = 0.0007). A cut-off of 11.76 for baseline BRI reached an 87.2% sensitivity and an 80% specificity for bronchial asthma diagnosis. In conclusion, BRI calculated with respect to baseline FEV1 should be useful in identifying asthmatic patients among subjects with airway hyperresponsiveness.

Comparison of bronchial responsiveness assessing dose-response slope between cough-variant asthma and classic asthma in young children

“…Bronchial hyperresponsiveness is a characteristic of asthma and provocative concentration causing a 20% fall in FEV1 (PC20_FEV1) derived from spirometry and two-point linear DRS are often used as parameters to determine BHR. 14,21,22) However, the conventional method is relatively hard to perform in young children and there have been previous studies comparing the conventional method and the IOS method; they suggested various cutoff points (such as PC40_Rrs6, 15) PC70_Rrs12, 23) and PC80_Xrs5 16) for diagnosing asthma as compatible for PC20_FEV1. In this study, we examined PC40_Rrs5 and PC80_Xrs5 in the classic asthma group and the CVA group.…”

Bronchial reactivity indices are determinants of health-related quality of life in patients with stable asthma

“…Of the three bronchial reactivity indices analysed, BRI shows the closest relationship with HRQL (table 3). It has previously been shown to discriminate better than DRS or CIR between subjects with or without asthma with AHR 19. It is possible that the BRI's closer to normal distribution confers on it a greater discriminating capacity when compared with the other indices of bronchial reactivity.…”

“…Unlike the sensitivity analysis, bronchial reactivity seems to more adequately reflect the severity of the response, as it assesses the intensity of the bronchoconstriction 17 18. In addition, it has been shown to be more useful in identifying patients with asthma19 and in maintaining a better relationship with the degree of oxidative stress of these patients 20…”

Obesity in women with asthma: Baseline disadvantage plus greater small‐airway responsiveness

“…Linear regressions (adjusted on variables that differed between groups) were used to test for obesity‐group effects at five levels: (i) baseline values, (ii) sensitivity as measured by the PD20 for each patient, 26–28 (iii) percent responsiveness values at the end of methacholine testing (PD20 percent change values, also known as airway responsiveness), (iv) the closing index (% change in FVC/% change in FEV1) 16 and (v) percent reversibility.…”

“…CT, computed tomography; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity Spirometry in a seated position Spirometry in a supine position FVC ≥ 90% of seated position? Spirometry in a supine position Isotonic saline nebulization CT First dose of methacholine Spirometry in a supine position FEV1 and FVC ≥ 80% of seated position?Linear regressions (adjusted on variables that differed between groups) were used to test for obesity-group effects at five levels: (i) baseline values, (ii) sensitivity as measured by the PD20 for each patient,[26][27][28] (iii) percent responsiveness values at the end of methacholine testing (PD20 percent change values, also known as airway responsiveness), (iv) the closing index (% change in FVC/% change in FEV1)16 and (v) percent reversibility.…”