Updating clinical practice recommendations: is it worthwhile and when?

BACKGROUND: Keeping clinical practice recommendations up-to-date with a continually evolving evidence base presents challenges. Resources required to update recommendations compete with those needed to evaluate newer treatments.
METHODS: We describe an approach developed by the UK National Institute for Health and Clinical Excellence (NICE) for updating clinical practice recommendations for new interventional procedures and we evaluate relevant initial experience of using this system. Depending on whether evidence for a procedure is judged adequate or inadequate for safety and efficacy, use in clinical practice is usually recommended with either "normal" or "special" arrangements for patient consent, data collection and institutional oversight, respectively. We examined whether differences in the state of the evidence at the initial and the updated appraisal of procedures were associated with changed recommendations.
RESULTS: Since 2008, updating of recommendations focuses on procedures with initially inadequate evidence. "Special arrangements" recommendations about eleven procedures were updated after 3.3-6.5 years (median, 5.3 years), and recommendations for six were changed to "normal arrangements." Overall, procedures with changed ("special-to-normal") recommendations had a greater increase in the number of patients included in observational studies published since the initial guidance.
CONCLUSIONS: Procedures with changed ("special-to-normal") recommendations generally had greater increases in their evidence base. Although uncertainties about optimal methods for keeping evidence-based recommendations up-to-date remain, this experience should be useful to policy makers in developing processes for prioritizing scarce resources for updating clinical practice recommendations. Further studies are needed about the value placed on "updated" recommendations by clinicians, policy-makers, and patients.