Mj. Sculpher et Mj. Buxton, THE EPISODE-FREE DAY AS A COMPOSITE MEASURE OF EFFECTIVENESS - AN ILLUSTRATIVE ECONOMIC-EVALUATION OF FORMOTEROL VERSUS SALBUTAMOL IN ASTHMA THERAPY, PharmacoEconomics, 4(5), 1993, pp. 345-352
The construction of a composite effectiveness measure was explored usi
ng clinical data collected routinely in trials of drug therapies for a
sthma. The measure is the episode-free day (EFD), where an 'episode' i
s either an asthma attack, the need for rescue medication, sleep distu
rbance caused by asthma, or an adverse event. The EFD measure was used
in a retrospective cost-effectiveness analysis of a previous Phase II
I controlled clinical trial of formoterol versus salbutamol, in which
145 patients with bronchial asthma were randomised to receive maintena
nce therapy with either inhaled formoterol or inhaled salbutamol over
a 12-week period. Average and incremental cost-effectiveness ratios we
re assessed for the 2 drugs in terms of the total expected cost of dru
g plus rescue therapy, and EFD rates. The analysis suggests that, with
relatively little addition to clinical data collection, economically
and clinically meaningful composite measures can be constructed to ass
ist in making cost-effectiveness comparisons between alternative asthm
a therapies.