Background: The Checklist for the Reporting of Updated Guidelines (CheckUp) was recently developed. However, so far, no systematic assessment of the reporting of updated clinical guidelines (CGs) exists. We aimed to examine (1) the completeness of reporting the updating process in CGs and (2) the inter-observer reliability of CheckUp.

Methods: We conducted a systematic assessment of the reporting of the updating process in a sample of updated CGs using CheckUp. We performed a systematic search to identify updated CGs published in 2015, developed by a professional society, reporting a systematic review of the evidence, and containing at least one recommendation. Three reviewers independently assessed the CGs with CheckUp (16 items). We calculated the median score per item, per domain, and overall, converting scores to a 10-point scale. Multiple linear regression analyses were used to identify differences according to country, type of organisation, scope, and health topic of updated CGs. We calculated the intraclass coefficient (ICC) and 95% confidence interval (95% CI) for domains and overall score.

Results: We included in total 60 updated CGs. The median domain score on a 10-point scale for presentation was 5.8 (range 1.7 to 10), for editorial independence 8.3 (range 3.3 to 10), and for methodology 5.7 (range 0 to 10). The median overall score on a 10-point scale was 6.3 (range 3.1 to 10). Presentation and justification items at recommendation level (respectively reported by 27 and 38% of the CGs) and the methods used for the external review and implementing changes in practice were particularly poorly reported (both reported by 38% of the CGs). CGs developed by a European or international institution obtained a statistically significant higher overall score compared to North American or Asian institutions (p = 0.014). Finally, the agreement among the reviewers on the overall score was excellent (ICC 0.88, 95% CI 0.75 to 0.95).

Conclusions: The reporting of updated CGs varies considerably with significant room for improvement. We recommend using CheckUp to assess the updating process in updated CGs and as a blueprint to inform methods and reporting strategies in updating.