|This project's final research report is expected to be available by July 2019.|
Peer review of PCORI-funded research helps make sure the report presents complete, balanced, and useful information about the research. It also assesses how the project addressed PCORI’s Methodology Standards. During peer review, experts read a draft report of the research and provide comments about the report. These experts may include a scientist focused on the research topic, a specialist in research methods, a patient or caregiver, and a healthcare professional. These reviewers cannot have conflicts of interest with the study.
The peer reviewers point out where the draft report may need revision. For example, they may suggest ways to improve descriptions of the conduct of the study or to clarify the connection between results and conclusions. Sometimes, awardees revise their draft reports twice or more to address all of the reviewers’ comments.
Peer reviewers commented, and the researchers made changes or provided responses. Those comments and responses included the following:
- Reviewers asked for more information about missing data, and specifically about whether missing data items might differ between the group practice and contracted-care clinics. The researchers responded that since the study data set contained the opioid prescription history of 96 percent of the patients in both groups, concerns about the effects of differences between groups would be limited.
- Reviewers questioned the generalizability of the study results since the researchers conducted the study within one health system, whereas a new state guideline would affect statewide opioid treatment decisions. The researchers acknowledged this concern but noted that the new state guideline was similar to the recommendations from the Centers for Disease Control and Prevention, which would make the results more relevant nationally than they would be without the guideline.
- Reviewers expressed concern about the choice of analysis for studying differences in adverse events based on dose reductions in the intervention and control groups. The analyses focused on the within-time segment slope—dose reduction, risk stratification and monitoring--without measuring the slope during the baseline period. The researchers explained that the dose-reduction slopes were very different in each time segment, so looking at the data across time segments might result in erroneous conclusions.
- Reviewers expressed concern about the timing of the study baseline period, which extended into the year after state opioid dosing guidelines changed. The researchers explained that they wanted to allow time for any initial, transient dose reductions related directly to the new guidelines to occur before starting their measurement. This also allowed time for the dose-reduction initiative to gain momentum.
- Reviewers expressed concern about how the researchers formed the study cohort, since individual patients could be eligible for inclusion during some quarters and ineligible for others, depending on their opioid prescriptions. Reviewers preferred a more stable sample that included the same patients throughout, marking them clearly as long-time opioid users. The researchers disagreed, stating that including only patients who were chronic users throughout would result in a much reduced and less-generalizable population, while keeping patients in the sample even if they no longer qualified, as chronic users would affect the validity of results. The open cohort employed here, meant that the researchers captured data for any patients in a particular quarter who met study criteria and their outcomes could be tracked for that period of time.
Conflict of Interest Disclosures
View the COI disclosure form.
Results of This Project
Tackling Chronic Pain While Reducing Opioid Use
This feature story about the study includes a look at a Washington State health system's use of a clinical plan that has succeeded in lowering patients’ opioid doses.
^Kaiser Permanente acquired Group Health Cooperative in February, 2017.