A Living Systematic Review to Support Health Technology Assessment: The CADTH Experience

Article type
Weeks L1, Kim J1, Lachance C1, Carson E1
1Canadian Agency for Drugs and Technologies in Health
Background: Living systematic reviews (LSRs)–systematic reviews that are continuously updated as new evidence becomes available–are increasingly being used to support clinical practice and guideline development. LSRs are also well suited to support health technology assessment (HTA), although to date we are unaware of an LSR being conducted by an HTA organization.

Objectives: To describe the Canadian Agency for Drugs and Technologies in Health (CADTH)’s experience conducting their first LSR as part of an HTA on the topic of stereotactic ablative radiotherapy for the treatment of oligometastatic cancer. Challenges and lessons learned will be discussed.

Methods: Throughout the development of the HTA protocol, targeted conversations were had between the LSR clinical research team and individuals working on other aspects of the HTA, including health economists, qualitative researchers, medical librarians, project managers, knowledge mobilization officers, patient engagement officers, and members of the publishing team. The purpose was to explore process challenges and implications of the living model on other aspects of HTA conduct and reporting. Detailed notes were taken, and decisions documented. Throughout the conduct of the LSR, through bi-weekly team meetings, challenges were identified, and solutions brainstormed.

Results: Methods outlined in the Guidance for the Production and Publication of Cochrane Living Systematic Reviews were primarily followed, with some adjustments to suit the CADTH and HTA context. For example, monthly search updates were not deemed possible due to competing demands of the medical librarians. Monthly alerts are instead being conducted during the conduct of the baseline review and, once the review transitions to living mode, updates will be conducted every three months for electronic databases and every six months for grey literature. Decision rules were established a priori, including both qualitative and quantitative signals, to guide decisions about when to incorporate new evidence into an analysis. The decision for the review to remain in living mode will be revisited annually and informed by the level of priority for decision-makers, the level of uncertainty that remains in the clinical evidence, and the existence of ongoing studies. Several process changes were required including to project schedule templates, engagement of clinical experts and peer reviewers, patient engagement, publishing, and knowledge mobilization.

Conclusions: With rapid health technology innovation and increasing attention to reassessment and disinvestment decisions, new models for evidence synthesis are needed. LSRs show promise to support HTA and will be used as appropriate in future CADTH HTAs, but processes and methods must also balance rigour and timeliness.

Patient Involvement: Throughout the conduct of the LSR, CADTH is engaging people with oligometastatic cancer, guided by the belief that patients have knowledge, perspectives, and experiences that are unique and contribute essential evidence for HTA.