Commonly used methods for guideline development and dissemination do not en
able developers to tailor guidelines systematically to specific patient pop
ulations and update guidelines easily. We developed a web-based system, ALC
HEMIST, that uses decision models and automatically creates evidence-based
guidelines that can be disseminated, tailored and updated over the web. Our
objective was to demonstrate the use of this system with clinical scenario
s that provide challenges for guideline development. We used the ALCHEMIST
system to develop guidelines for three clinical scenarios: (1) Chlamydia sc
reening for adolescent women, (2) antiarrhythmic therapy for the prevention
of sudden cardiac death; and (3) genetic testing for the BRCA breast-cance
r mutation. ALCHEMIST uses information extracted directly from the decision
model, combined with the additional information from the author of the dec
ision model, to generate global guidelines. ALCHEMIST generated electronic
web-based guidelines for each of the three scenarios, Using ALCHEMIST, We d
emonstrate that tailoring a guideline for a population at high-risk for Chl
amydia changes the recommended policy for control of Chlamydia from contact
tracing of reported cases to a population-based screening programme. We us
ed ALCHEMIST to incorporate new evidence about the effectiveness of implant
able cardioverter defibrillators (ICD) and demonstrate that the cost-effect
iveness of use of ICDs improves from $74 400 per quality-adjusted life year
(QALY) gained to $34 500 per QALY gained. Finally, we demonstrate how a cl
inician could use ALCHEMIST to incorporate a woman's utilities for relevant
health states and thereby develop patient-specific recommendations for BRC
A testing; the patient-specific recommendation improved quality-adjusted li
fe expectancy by 37 days. The ALCHEMIST system enables guideline developers
to publish both a guideline and an interactive decision model on the web.
This web-based tool enables guideline developers to tailor guidelines syste
matically to update guidelines easily, and to make the underlying evidence
and analysis transparent for users.