Abstract
Background The randomised controlled trial (RCT) is considered the ‘gold standard’ for establishing
treatment efficacy or effectiveness of an intervention, but its data do not infer
response in an individual patient. Individualised clinical care, a fundamental principle
in complementary and alternative medicine (CAM), including homeopathy, seems well
disposed in principle to being researched by single-patient (N-of-1) study design.
Guidelines for reporting N-of-1 trials have recently been developed.
Objective To overview the current status in the literature of the N-of-1 method and its application
in medicine, including CAM. To consider whether the N-of-1 trial design offers an
opportunity for novel research in homeopathy.
N-of-1 Trial Design The N-of-1 trial applies the principles of the conventional crossover, blinded, RCT
design. The treatment under study and the comparator are repeated in a randomised
order, and with suitable washout time, over a defined period. N-of-1 design is constrained
for use in chronic stable conditions, and for interventions that have quick onset
and cessation of effect, with modest or negligible carryover. Outcome data can be
aggregated and interpreted for the individual subject; they can also be pooled with
data from several similar N-of-1 trials, enabling more generalisable conclusions.
The N-of-1 Trial in CAM The typical individualisation of patient care can be accommodated in N-of-1 study
design if the patient and the specific therapeutic intervention are selected within
the constraints of the method. Application of the N-of-1 method in CAM has been advocated
but has been mainly limited, in practice, to a small number of studies in herbal and
traditional Chinese medicine.
The N-of-1 Trial in Homeopathy Individualised homeopathy can be accommodated for investigation within the same methodological
constraints; less in-depth homeopathic approaches to prescribing are also amendable
to investigation using the N-of-1 method. No such studies have been published. We
identify three main targets in its ready applicability to homeopathy: (1) to optimise
clinical care in an individual patient; (2) to investigate whether the outcomes of
treatment using homeopathy differ from those of placebo; (3) to aggregate data from
a series of N-of-1 trials to enable broader conclusions about a group of patients
or intervention.
Conclusion The N-of-1 trial design offers important new investigative possibilities in homeopathy
and should be explored as a means to optimise individualised health care or investigate
effectiveness of the homeopathic intervention compared with placebo in individual
subjects.
Keywords
complementary and alternative medicine - homeopathy - N-of-1 trial - single-patient
trial - research methods
