On 2017 Sep 28, Guan-Hua Huang commented:

None

On 2017 Sep 28, Guan-Hua Huang commented:

Dear Dr. Bryson:

Thank you very much for your questions.

The variance between the outcomes registered on clinical trials.gov and those reported in JAMA Surgery resulted from our delay in updating the final project outcomes. Since the original protocol was written in Chinese and did not translate fully to English at the time, our research nurse started with one primary outcome first, and there was a delay in updating the others. Thank you so much for bringing this important omission to our attention. All outcomes have now been accurately registered on clinical trials.gov. In addition, we have now updated and confirmed that the research protocol, which documented all outcomes and was published on the JAMA Surgery website as a supplement, was approved by the institutional review board at the study site.

With regards to the sample size estimation, we were also delayed in posting these results. Initially, we had difficulty finding similar studies to estimate the effect size for delirium, as well as in identifying appropriate methodologic approaches to be used in power analysis for cluster-randomized controlled trials when a binary outcome is modeled. We have now updated to include the power analysis for the cluster continuous outcome and found that 270 patients were required for 80% power, and 360 patients were required for 90% power. In the end, we managed to recruit 377 patients, and post hoc analysis indicated that our study was powered at 81% for delirium.

Thank you for the careful read, and for bringing these important issues to our attention.

We would be glad to answer any further questions.

On 2017 Sep 20, Greg Bryson commented:

Would the authors (or editors) comment on: a) the variance between outcomes registered on ClinicalTrials.gov, those reported in the published manuscript, and those described in the protocol appended as an electronic supplemental file. b) the absence of a formal sample size estimate from the published report (CONSORT 7a) or the protocol (SPIRIT 14). Thank you.

On 2017 Sep 20, Greg Bryson commented:

Would the authors (or editors) comment on: a) the variance between outcomes registered on ClinicalTrials.gov, those reported in the published manuscript, and those described in the protocol appended as an electronic supplemental file. b) the absence of a formal sample size estimate from the published report (CONSORT 7a) or the protocol (SPIRIT 14). Thank you.

On 2017 Sep 28, Guan-Hua Huang commented:

None