Results Summary

What was the research about?

About 60 million people in the United States live with chronic pain that lasts for months or years. Doctors sometimes treat chronic pain with medicines called opioids. But patients who use opioids for a long time are at increased risk for serious health problems, such as addiction, overdose, car crashes, and injuries. The research isn’t clear if using opioids for a long time helps patients control their pain.

A network of clinics in Washington State started a program to reduce opioid doses prescribed for patients with chronic pain. The program had two phases:

  • Dose-lowering. Doctors prescribed lower doses of opioids for many patients with chronic pain using opioids long-term. This phase started in 2007.
  • Monitoring. Starting in 2010, clinics increased monitoring of patients taking opioids long-term and created care plans for them. Clinic pharmacies also changed the way patients refilled opioid prescriptions.

In this study, the research team wanted to learn if the program reduced the risks that go along with long-term opioid use. The study compared patients who received care at clinics with and without the program.

What were the results?

Patients who received care at clinics with and without the program had similar

  • Rates of opioid overdoses
  • Ratings of pain severity
  • Rates of injuries and car crashes

During the dose-lowering phase, the rate of opioid overdoses decreased at clinics with the program, but not more than it did for clinics without the program.

Who was in the study?

The study looked at medical and public records for 31,142 adult patients who used opioids long-term. The research team also interviewed 1,588 of these patients.

What did the research team do?

The research team reviewed information on overdoses from patient records for three time periods. The first was before the dose-lowering phase started. The second was for the dose-lowering phase. The third was for the monitoring phase. The team also looked at numbers of car crashes and injuries. Four years after the program started, the team interviewed patients about their experience with pain. They compared patients from clinics with and without the program.

A group of patients and patient advocates helped design the study and review the results.

What were the limits of the study?

Policies about prescribing opioids changed in Washington State during the study period. The new policies may have changed how doctors’ prescribed opioids in both sets of clinics. Fewer patients received care at clinics without the program than at clinics with the program. As a result, it was hard to compare the groups of clinics.

Future research could study more people to better understand if reducing opioid doses helps lower the number of overdoses.

How can people use the results?

Clinics can use the results of this study when thinking about how to reduce opioid doses for patients with chronic pain.

Final Research Report

View this project's final research report.

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Peer-Review Summary

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

Project Information

Michael Von Korff, ScD
Kaiser Foundation Health Plan of Washington^
Evaluation of a Health Plan Initiative to Mitigate Chronic Opioid Therapy Risks

Key Dates

December 2013
October 2018

Study Registration Information

^Kaiser Permanente acquired Group Health Cooperative in February, 2017.


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Last updated: March 14, 2024