Pm. Dorinsky et al., Use of changes in symptoms to predict changes in lung function in assessing the response to asthma therapy, CLIN THER, 23(5), 2001, pp. 701-714
Background: The majority of adult patients with asthma are managed by prima
ry care providers. Although there is no generally accepted gold standard fo
r the assessment of asthma severity in general practice, treatment decision
s and modifications to therapy are strongly influenced by patients' symptom
s and history of asthma medication use.
Objectives: The primary goal of this study was to determine whether there i
s a correlation between changes in asthma symptoms during treatment and cha
nges in lung function, as measured by peak expiratory flow (PEF). A, second
ary goal was to compare the relative efficacy tin terms of improvement in a
sthma symptoms and lung function) of 3 commonly used asthma treatments: inh
aled fluticasone propionate, inhaled salmeterol xinafoate, and oral zafirlu
kast.
Methods: This was a retrospective comparison employing regression analyses
of asthma symptom and lung function data from 2890 male and female adolesce
nt and adult patients with persistent asthma who were enrolled in 8 randomi
zed, double-blind, double-dummy, parallel-group studies. Data on patients'
self-rated symptoms, PEF supplemental albuterol use, nighttime awakenings,
and frequency of asthma exacerbations were used to ascertain whether there
was a correlation between changes in asthma symptoms and changes in pulmona
ry function, and to compare treatment effects.
Results: Changes in patients' ratings of asthma symptoms after treatment wi
th study medications showed a strong correlation with changes in lung funct
ion. Similarly, changes in lung function were strongly correlated with chan
ges in supplemental beta-agonist use and quality of life. In addition, flut
icasone or salmeterol treatment resulted in significantly greater increases
in mean morning PEF (P < 0.001), significantly greater decreases in sympto
m scores (P less than or equal to 0.004), significantly fewer nights with a
wakenings due to symptoms (P less than or equal to 0.017), and significantl
y greater reductions in supplemental beta-agonist use (P < 0.001) compared
with zafirlukast treatment or placebo. Patients treated with fluticasone or
salmeterol also experienced significantly lower rates of asthma exacerbati
on (3%) during treatment than did those receiving zafirlukast (7%) or place
bo (12%) (P < 0.001 and P = 0.015, fluticasone and salmeterol, respectively
).
Conclusion: These findings support the validity of primary care practitione
rs' basing asthma-management decisions on patients' symptoms.