Browsing This

Persistence of Airway Obstruction and Hyperresponsiveness in Subjects With Asthma Remission: Response to Bronchodilators

Published in Asthma

Persistence of Airway Obstruction and Hyperresponsiveness in Subjects With Asthma Remission: Response to BronchodilatorsIn asthmatics “in remission,” improvement in FEVi following bronchodilator was small although larger than in controls, with a percent change from baseline values ranging from —1.1 to 14.1 percent; mean, 5.7 ±0.8 percent (controls: —4.4 to 10.5 percent; mean, 2.5 ±0.6 percent; p=0.004). After 200 fig of inhaled albuterol, FEF25-75% increased 2.2 to 50 percent from baseline; mean, 17.3 ±2.6 percent) (controls: —4.3 to 39.8 percent; mean, 13.5±2.3 percent; NS). The increase in FEF25-75% was the sole parameter that was statistically different when the five hyperreactive control subjects were either kept in the control group or replaced: mean response with hyperreactive subjects replaced was 11.5 ±1.9, p=0.024).
Diurnal Changes in PEFR
Diurnal variations of PEFR were observed over a 2-week period. Maximal daily change of PEFR in percent during that period (Max APEFR) varied from 2.1 to 30.1 percent with a mean of 12.3 ±1.3 (controls: 1.4 to 14.1 percent; mean, 7.0 ±0.8; p=0.021). Buy inhalers online More info Ten asthmatics “in remission” had a max APEFR >15 percent (none in controls). No subject had a mean APEFR (mean of daily changes in PEFR during the 2-week period) >10 percent. It went from 1.1 to 8.9 percent (mean, 4.6 ±0.4) in asthmatics “in remission” (controls: 0.03 to 7.9; mean, 2.9 ±0.3; NS; Fig 3).
Airway Response to Methacholine
Nineteen subjects “in remission” had an increased response to methacholine (Fig 4). Their geometric mean PC20 was 12.2 mg/ml; PC20 was <8 mg/ml in 9 and between 8 and 20 mg/ml in 10 others. Two subjects showed a >20 percent fall in FEVi after saline solution inhalation and one refused to perform the test. Three subjects had a PC20 between 20 and 64 mg/ml and five had > 128 mg/ml. In controls, geometric mean PC20 methacholine was 41.3 mg/ml (p=0.002 compared with controls) and was distributed as follows (number of subjects): under 8 mg/ ml, n=5; between 8 and 20 mg/ml, n=3; between 20 and 128 mg/ml, n=11; and without response to a concentration of 128 mg/ml, n=11. There was no significant correlation among PC20 and atopy (number of positives in skin prick tests), duration of asthma, or duration of asthma remission. However, PC20 was correlated with age at the time of diagnosis of asthma (r= —0.419, p=0.0395) and with age at the time of remission (r= —0.549, p=0.0056, Fig 4). Mean age at the time of remission was 22.7 ±2.5 years; most subjects experienced remission of their asthma between 11 and 20 years of age.

Figure-3

Figure 3. There was no significant difference between exasthmatics and controls for mean daily variations in PEFR over a 2-week period (AR: 4.6 ±0.4 percent; C: 2.9 ±0.3 percent). However, the difference was significant between ex-asthmatics and controls for the maximal daily variation in PEFR observed during that period (AR: 12.3 ± 1.3 percent; C: 7.0 ±0.8 percent, p=0.021), although these fluctuations of airway caliber are very small.

Figure-4

Figure 4. There was no significant correlation between PC20 and duration of asthma or duration of remission of asthma. There was, however, a correlation between the age of onset of asthma and the actual PC20 (r= -0.419, p=0.0395) and the age at the time of remission and actual PC20 (rs —0.549, p=0.0G56).