Randomized clinical trials in single patients during a 2-year period
E. B. Larson, A. J. Ellsworth and J. Oas
Department of Medicine, School of Medicine, University of Washington, Seattle.
OBJECTIVE--To describe the feasibility of a single patient trial (SPT)
service and study the influence of formal SPTs on therapeutic precision.
DESIGN--Descriptive and evaluate study of SPTs. All planned trials were
double-blind, randomized, multiple crossover trials. Other key features of
individual trials were random assignment of order and assessment of
predetermined explicit outcomes. Patients and physicians rated level of
confidence in treatment before and after the SPT on visual analog scales.
SETTING--Two-year experience (September 1988 to September 1990) of an SPT
trial referral service available to physicians in an academic medical
center. OUTCOME MEASURES--The number of planned and completed SPTs;
proportion of completed trials yielding definitive answers; patient- and
physician-rated levels of confidence in treatment pre- and post-SPT;
time-motion studies to estimate resource consumption (costs) for selected
SPTs. RESULTS--Of 34 completed trials, 17 were judged to give definitive
results whereas 17 showed trends only. Results favored active treatment in
16 trials that led to treatment being continued (nine patients) or started
(seven patients). Treatment was discontinued (seven patients) or not
started (11 patients) based on 18 trial results that demonstrated active
treatment was ineffective (seven), harmful (two), or apparently equivalent
(nine). Most patients (65%) reported no change in their already high level
of confidence in therapy as a result of trials, whereas physicians'
confidence levels in therapy either increased or decreased post-SPT
depending on the direction of trial results. Patients consistently rated
the SPT service as extremely useful. Time-motion estimates indicate that
16.75 staff hours were spent per trial leading to a direct cost estimate of
approximately $450 to $500 per trial. CONCLUSION--We conclude that an SPT
service is feasible, trial costs compare favorably with other conventional
services, and clinicians appear to gain confidence and precision from SPTs.
When patients or clinicians are uncertain about the value (including the
possibility of side effects) of treatment for symptomatic chronic diseases,
we believe an SPT can be offered to a patient and will likely yield results
that will effect subsequent treatment.
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