Annual Change of Respiratory Functions in Adult Patients With Asthma: The Potential of Antiasthma Treatments for Many Years to Repair Irreversible Changes of the Airway.
J Asthma. 2010 Aug 16. Muraki M, Nisikawa Y, Naito E, Sato R, Iwanaga T, Tohda Y. Department of Respiratory Medicine and Allergology, Kinki University School of Medicine, Osakasayama, Osaka, Japan.
Background: Little is known regarding annual changes of respiratory functions among patients with asthma after asthma symptoms enter remission.
Objective: Annual changes of respiratory function and influence of patient characteristics and treatment variables on these changes were assessed in patients with adult asthma.
Methods: Respiratory function (pre- and postbronchodilator forced expiratory volume in one second [FEV(1)] and reversibility by short-acting beta(2)-agonist) and their changes were retrospectively investigated and relationships between these changes, after symptomatic remission, and patient characteristics and treatments were analyzed in adult outpatients with asthma who had undergone spirometry (including a reversibility test) >/=5 times in >5 years.
Results: In patients >/=40 years old, or with disease duration >/=10 years or receiving treatment for severe asthma (steps 4-5, high-dose inhaled glucocorticosteroids, or addition of other medications), both pre- and postbronchodilator FEV(1) values were significantly lower (p < .05). Mean annual change of prebronchodilator FEV(1) (Deltapre-FEV(1)), annual change of postbronchodilator FEV(1) (Deltapost-FEV(1)), and annual change of reversibility (Delta reversibility) were -13.8 +/- 59.7 ml/year, -25.9 +/- 51.0 ml/year, and -0.56% +/- 1.89%/year, respectively. Multivariate analysis after stepwise selection for variables in patient characteristics or treatments showed that disease duration >/=10 years contributed to annual improvement of respiratory functions (Deltapre-FEV(1): odds ratio [OR] 1.57, 95% confidence interval [CI] 1.01-2.46; Deltapost-FEV(1): OR 2.13, 95% CI 1.25-3.66), treatment with long-acting beta(2)-agonists (LABAs) contributed to annual improvement of respiratory function (Deltapre-FEV(1): OR 2.05, 95% CI 1.23-3.16; Deltapost-FEV(1): OR 1.78, 95% CI 1.11-2.87), and poor compliance contributed to annual worsening of respiratory functions (Deltapre-FEV(1): OR 0.43, 95% CI 0.24-0.76; Deltapost-FEV(1): OR 0.39, 95% CI 0.22-0.70). In addition, duration of disease >/=10 years and severe treatment (steps 4-5) from the beginning contributed to decreasing Deltareversibility (OR 0.55, 95% CI 0.34-0.87 and OR 0.50, 95% CI 0.29-0.83, respectively).
Conclusions: Long-term treatments for asthma are expected to normalize respiratory dysfunction, which cannot be repaired in the short term. Treatment with LABAs and patient compliance may be the most important factors associated with annual improvement of respiratory functions.