Adapting to change: experiences and recommendations from the Pain Management Collaboratory on modifying statistical...

Best practices for clinical trials stipulate that statistical analysis plans (SAPs) need to be finalized before initiation of any analysis. However, there is limited guidance about when changes to SAPs are acceptable and how these changes should be incorporated into the research plan with appropriate documentation.

We conducted a survey of 12 pragmatic clinical trials (PCTs) in the Pain Management Collaboratory that evaluated nonpharmacological interventions for pain to assess the following SAP information: (1) location of statistical analysis details, (2) types of statistical analyses planned, (3) sponsor requirements, (4) templates used for development, (5) publication plan, (6) changes since trial launch, (7) process of documenting changes, and (8) process of updating the trial registry.

All 12 PCTs provided details of their SAPs for the primary outcomes in the institutional review board-approved trial protocol; 8 included plans for secondary outcomes, and 6 included plans for tertiary/exploratory outcomes. Most PCTs made SAP changes after trial initiation, many as a result of COVID-19-related issues. Eleven of the PCTs were actively recruiting participants. Changes were made to sample size, study design, study arms, and analytical methods, all before the data lock/unblinding. In all cases, justification for the changes was documented in the trial protocol or SAP, signed off by the trial biostatistician and principal investigator, and reviewed/approved by an institutional review board, data and safety monitoring board, or sponsor.

We recommend that SAP changes can be acceptable up to the time of data lock/unblinding. To maintain full transparency and necessary rigor, clear documentation of such changes should include details, rationale, date(s) such changes were implemented, and evidence of approval by relevant oversight bodies.