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Persistence of Airway Obstruction and Hyperresponsiveness in Subjects With Asthma Remission: Results

Published in Asthma

Results were similar whether the five hyperreactive subjects were replaced or not, except for bronchodilator response, as commented in this section. Therefore, the results presented are those of the 30 ex-asthmatics in comparison to the 30 initial controls, including these 5 hyperreactive subjects.
Our subjects reported no symptom attributed to asthma or any need for antiasthma medication for periods of 2 to 25 years (mean [±SEM], 9.6 ±1.3). Age at the onset of asthma was from 0 to 33 years (mean, 10.5 ±1.8) and duration of symptomatic asthma was from 2 to 33 years (mean, 12.4±1.7). Remission of asthma had occurred in childhood in 12 subjects and followed cessation of a specific antigenic exposure to house pets in 9 subjects and after moving to another country in 2 others. Ten exasthmatics and two controls had past immunotherapy. Eleven asthmatics “in remission and 10 controls had a family history of asthma and, respectively, 16 and 21 subjects had a family history of atopy (Table 1).
Expiratory Flows
Baseline FEVi in the group “in asthma remission” varied between 62 and 117 percent of predicted value, with a mean of 91.0 percent (control group: 84 to 133 percent; mean, 104.1 ±1.9 percent; p=0.001) (Table 2). Four subjects had a FEVi <80 percent of predicted values (none in controls), but their FEVi/FVC ratio was >70. The FVC values were from 77 to 128 percent of predicted with a mean of 97.8 ±2.3 percent (controls: 86 to 131 percent; mean, 104.0±1.8 percent; NS) More info http://antimicrobialmed.com. Baseline FEF25-75% varied from 33 to 149 percent of predicted with a mean of 70.5 ±4.8 percent (controls: 66 to 145 percent; mean, 89.0 ±4.0 percent; p=0.008). The FEVi/FVC varied from 75 to 114 percent, with a mean of 93.3 ±1.7 percent (controls: 93 to 109 percent; mean, 100.2 ±0.9 percent; p=0.008) (Fig 1). The FEF25-75% was reduced <60 percent of the predicted value in 12 asthmatics “in remission” (none in controls) and between 60 and 65 percent of predicted values in 2 (4 controls). Baseline values for pulmonary volumes are shown in Figure 2. Residual volume (RV) ranged from 61 to 259 percent, with a mean of 140.7 ± 8.0 percent (controls: 45 to 204; mean, 118.8 ±5.7 percent; p=0.039) and functional residual capacity (FRC) varied from 71 to 222 percent, with a mean of 113.6 ±5.6 percent (controls: 63 to 146 percent; mean, 99.4 ±3.6 percent; p=0.027). Eleven asthmatics “in remission” had both a FEF25-75% <60 percent and RV >120 percent (none in controls) and 2 had a FEF25-75% between 60 and 65 percent of predicted values with RV >120 percent (2 controls).

Figure-1

Figure 1. There was a significant difference between the “asthmatics in remission” (AR) and controls (C), for FEVi (mean, AR: 91.0±2.5 percent; C: 104.1 ±1.9 percent, p=0.001), FEF25-75% (mean, AR: 70.6±4.8 percent; C: 89.0±4.0 percent, p=0.008), FEVi/FVC (mean, AR: 93.3 ±1.7 percent; C: 100.2 ±0.9 percent, p=0.008). FVC was not significantly different between both groups (mean, AR: 97.8±2.3 percent; C: 104.0±1.8 percent).

Figure-2

Figure 2. Residual volume (RV) was slightly higher (p>0.025 with p=0.039) in asthmatics in remission (AR) compared with controls (C) (mean percent predicted: 140.7 ±8.0 percent and 118.0 ±5.7 percent, respectively). Similar observations were made for FRC (mean percent predicted, AR: 113.6 ±5.6 percent; C: 99.4 ±3.6 percent, p=0.027).