Use of Rescue Medication
The type of rescue medication (RM) varied across the eligible trials,
including antihistamines, naphazoline nitrate, topical antihistamines,
topical nasal corticosteroids, systemic corticosteroids, tramazoline
hydrochloride and levocabastine hydrochloride. We assessed the use of RM
in two different ways, depending on type of data that eligible studies
provided. First, a daily mean score was calculated by adding the total
number of different kinds of rescue medications used each day during the
pollen season divided by the total number of days in the pollen season.
Five studies with a total of 1,098 randomized patients provided enough
data to allow for a quantitative evidence synthesis based on the RM as a
daily mean score. In two studies10, 11, rescue
medication score was defined as daily usage on a 4-point scale (0= no
rhinitis medication; 1= topical nasal, ocular, or lung treatment apart
from corticosteroids; 2= systemic antihistamines; 3= systemic or topical
corticosteroids for nose or lung). When more than one rescue medication
was used on the same day, only the maximal score medication was
recorded. In the other three studies12-14, it was
measured on a 4-point scale (0-3 points), but it was not described
sufficiently how the score was generated. Overall, in the studies with
appropriate data, omalizumab statistically significantly reduced the use
of rescue medication mean score by a summary standardized mean
difference of -0.11 points (95% CI: -0.16, -0.05; p<0.001;
I2 = 62.9%) (Figure 4a).
Moreover, we assessed the use of rescue medication as daily mean
consumption, i.e. the average daily rescue antihistamine tablets
consumed by patients. Three studies with 797 randomized patients
provided enough data to allow for a quantitative evidence synthesis
based on the use of rescue medication assessed as mean daily
consumption. Overall, omalizumab statistically significantly reduced the
mean daily consumption of rescue medication with antihistamines by a
summary standardized mean difference of -0.21 (95% CI, -0.41, -0.01;
p=0.036; I2 = 85.7%) (Figure 4b).