Relationship between quality of life and clinical status in asthma: a factor analysis.

Many studies have shown that correlation between clinical asthma status and asthma-specific quality of life is only weak to moderate. However, this relationship has never been explored to determine whether the weakness is due to noise of measurement or whether quality of life is a distinct component of asthma health status. With a database from three clinical trials (n = 763), factor analysis was used to explore the relationships between quality of life, measured by the Asthma Quality of Life Questionnaire (AQLQ), and conventional measures of asthma clinical status (symptoms, airway calibre and rescue beta2-agonist use). The analysis revealed that although patients with severe, poorly controlled asthma tend to have worse quality of life than milder, well-controlled patients, overall asthma health status has four components (factors): asthma-specific quality of life; airway calibre; daytime symptoms and daytime beta2-agonist use, and night-time symptoms and night-time beta2-agonist use. The clean loading of all 21 outcomes onto four distinct and clinically identifiable factors suggests that, although some weakness of correlation between clinical indices and quality of life may be due to noise of measurement, it is mainly attributable to asthma health status being composed of distinct components.

Salmeterol added to inhaled corticosteroid therapy is superior to doubling the dose of inhaled corticosteroids: a randomized clinical trial.

This randomized, double-blind, double-dummy, parallel group clinical trial compared the efficacy and safety of adding salmeterol xinafoate to concurrent inhaled beclomethasone dipropionate therapy with doubling the dose of beclomethasone dipropionate in patients experiencing symptoms on low-dose beclomethasone. Salmeterol added to low-dose beclomethasone was superior (p < or = 0.05) to doubling the dose of beclomethasone in improving peak expiratory flow (PEF) and forced expiratory volume in 1 sec (FEV1), and in reducing symptoms of asthma, sleep loss, nighttime awakenings, and use of albuterol. Both treatment regimens had comparable safety profiles. In asthma patients inadequately controlled despite the use of low-dose inhaled corticosteroids (i.e., less than 400 microg per day), the addition of salmeterol may be a more effective treatment option than doubling the dose of inhaled corticosteroids.

A six-month, placebo-controlled comparison of the safety and efficacy of salmeterol or beclomethasone for persistent asthma.

BACKGROUND: There is a paucity of data comparing the long-term safety and efficacy of long-acting inhaled beta2-agonists versus low-dose inhaled corticosteroids in the treatment of asthma. OBJECTIVE: To compare the safety and efficacy of salmeterol xinafoate, beclomethasone dipropionate (BDP), and placebo over a 6-month treatment period in patients with persistent asthma. METHODS: Salmeterol (42 microg twice daily), BDP (84 microg four times daily), or placebo was administered via metered-dose inhaler to 386 adolescent and adult inhaled corticosteroid-naive patients in a randomized, double-blind, double-dummy, parallel-group study. Eligible patients demonstrated a forced expiratory volume in 1 second (FEV1) from 65% to 90% of predicted values. Pulmonary function, symptom control, frequency of asthma exacerbations, bronchial hyperresponsiveness (BHR) to methacholine challenge, and adverse events were assessed. RESULTS: There were few statistically significant differences between the two active treatments over 6 months of therapy. Asthma symptoms and lung function were significantly improved with both salmeterol and BDP compared with placebo (changes from baseline in FEV1 of 0.28 L (SE = 0.04) and 0.23 L (SE = 0.04), respectively, compared with 0.08 L (SE = 0.04); P < or = .014). There were no significant differences among the treatment groups with respect to the distribution of asthma exacerbations over time. Both salmeterol and BDP significantly reduced BHR compared with placebo (P < or = .033; changes from baseline of 1.29 (SE = 0.26) and 1.42 (SE = 0.24) doubling doses at 6 months, respectively, compared with 0.24 (SE = 0.29) doubling dose for placebo). No rebound effect in BHR was seen upon cessation of any of the three treatment regimens. There were no clinically important differences in the safety profiles among the three treatments. CONCLUSIONS: Both salmeterol and BDP are effective and well-tolerated when administered for 6 months to inhaled corticosteroid-naive patients with persistent asthma.

Lack of subsensitivity to albuterol after treatment with salmeterol in patients with asthma.

The development of tolerance to the bronchodilator effects of beta2-agonists used in asthma therapy has been the subject of debate. We conducted two placebo-controlled crossover studies to assess the bronchodilator response to a short-acting beta2-agonist before and after chronic therapy with salmeterol. Patients in one study were corticosteroid-naive; patients in the other study were using inhaled corticosteroids. Changes in FEV1 after cumulative doubling doses of inhaled albuterol were assessed after a 2-wk beta-agonist washout period, before administering study medication on Day 1, and again after 28 d of therapy. Ipratropium bromide was provided as rapid-relief treatment for asthma, and use of any beta2-agonist except the study treatment was prohibited. On both assessment days for salmeterol, and during placebo administration periods, significant increases from predose FEV1 values were observed beginning with the lowest dose of albuterol and continuing throughout the dose-response assessment (p