Objective To evaluate the reporting quality of single-patient (N-of-1) trials and protocols based on the CONSORT Extension for N-of-1 trials (CENT) statement and the standard protocol items: recommendations for interventional trials (SPIRIT) extension and elaboration for N-of-1 trials (SPENT) checklist to examine the factors that influenced reporting quality. Methods Four electronic databases were searched to identify N-of-1 trials and protocols from 2015 to 2020. Quality was assessed by two reviewers. We calculated the overall scores based on binary responses in which "Yes" was scored as 1 (if the item was fully reported), and "No" was scored as 0 (if the item was not clearly reported or not definitely stated). Results A total of 78 publications (55 N-of-1 trials and 23 protocols) were identified. The mean reporting score (SD) of the N-of-1 trials and protocols were 29.24 (0.89) and 29.61 (1.83), respectively. For the items related to outcomes, sample size, allocation concealment protocol, and informed consent materials, the reporting quality was low. Our results showed that the year of publication (t = -0.793, p = 0.872 for the trials and t = 1.352, p = 0.623 for the protocols) and the impact factor of the journal (t = 1.416, p = 0.619 for the trials and t = 0.359, p = 0.667 for the protocols) were not factors associated with better reporting quality. Conclusion With the publication of the CENT 2015 statement and the SPENT 2019 checklist, authors should adhere to the relevant reporting guidelines and improve the reporting quality of N-of-1 trials and protocols.

Background: N-of-1 trial is a desired and appropriate approach to assessing the efficacy and safety of traditional Chinese medicine (TCM) interventions. There have been an increasing number of N-of-1 trials for TCM published. However, a lack of preferred reporting guidance led in the general poor reporting quality of these trials. Due to the unique characteristics of TCM, the working group developed this CONSORT Extension for reporting N-of-1 Trials for Traditional Chinese Medicine (CENT for TCM) to assist TCM researchers in reporting N-of-1 trials for TCM. Methods: We registered CENT for TCM at the EQUATOR (Enhancing the QUAlity and Transparency Of health Research) Network (available at equator-network.org). The development was a comprehensive process through collection of the initial reporting items, two-round scientific Delphi consensus survey with 17 panelists, revision and formation of the final reporting checklist. Results: The checklist includes 25 items within six domains, eight items in which were extended and elaborated on the items of the CENT 2015 checklist. Explanation of the items were listed adequately considering the nature of TCM, introducing the concept of TCM syndrome differentiation and TCM interventions. Conclusions: CENT for TCM can be used to assess the completeness of the reporting of N-of-1 trials for TCM. The working group expect that CENT for TCM could be a practical tool to enhance the comprehensiveness and transparency of the design, implementation and reporting of N-of-1 trials for TCM.