Project Summary

This research project is in progress. PCORI will post the research findings on this page within 90 days after the results are final.

What is the research about?

More than 16 million people have surgery in the United States each year. After surgery, patients may have acute, or short-term, pain. Medicines, such as opioids and nonsteroidal anti-inflammatory drugs, or NSAIDs, can help patients manage their pain. But some pain medicines have risks. For example, patients may become addicted to opioids.

In this study, the research team is comparing opioids and NSAIDs. The team wants to see how well each works to help patients manage their pain after surgery. The team is also comparing the harms of each medicine.

Who can this research help?

Results may help patients, their families, and doctors when considering ways to manage pain after surgery.

What is the research team doing?

The research team is enrolling 900 patients from four health systems. All patients are scheduled to have gallbladder, hernia, or breast lump removal surgery. The team is assigning patients by chance to receive opioids or NSAIDs after their surgery. All patients are also receiving acetaminophen to help manage their pain.  

Then, the research team is surveying patients about their experiences after surgery. Patients rate their level of pain in the first week after surgery and again one, three, and six months later. Surveys ask patients about:

  • Side effects from the medicine
  • Quality of sleep
  • Quality of recovery
  • Trips to the emergency room for pain
  • How much pain affects their life
  • Use of drugs or alcohol

The research team is also looking at whether patients use NSAIDs or opioids in ways other than prescribed. Examples include taking more pills at one time or taking them more often than prescribed.

Patients who have had pain after surgery, healthcare providers, health insurers, and community groups are helping to plan and conduct this study.

Research methods at a glance

Design Element Description
Design Randomized controlled trial
Population 900 adults scheduled for gallbladder removal, hernia repair, or breast lump removal surgery
  • NSAIDs with acetaminophen
  • Opioids with acetaminophen

Primary: intensity of pain, safety (adverse medicine-related symptoms)

Secondary: patient-reported sleep disturbance, perception of improvement after treatment, pain interference, anxiety, depression, and quality of life; clinically important adverse events; substance use; opioid misuse; chronic pain; healthcare utilization related to pain; quality of recovery

Timeframe Timeframe Length of follow-up for collecting data on primary outcomes. View Glossary 1-week follow-up post-surgery for primary outcome

Project Information

Mark Bicket MD, PHD
University of Michigan
Comparing Analgesic Regimen Effectiveness and Safety After Surgery – The CARES Trial

Key Dates

December 2021
April 2026

Study Registration Information


Award Type
Health Conditions Health Conditions These are the broad terms we use to categorize our funded research studies; specific diseases or conditions are included within the appropriate larger category. Note: not all of our funded projects focus on a single disease or condition; some touch on multiple diseases or conditions, research methods, or broader health system interventions. Such projects won’t be listed by a primary disease/condition and so won’t appear if you use this filter tool to find them. View Glossary
Populations Populations PCORI is interested in research that seeks to better understand how different clinical and health system options work for different people. These populations are frequently studied in our portfolio or identified as being of interest by our stakeholders. View Glossary
Intervention Strategy Intervention Strategies PCORI funds comparative clinical effectiveness research (CER) studies that compare two or more options or approaches to health care, or that compare different ways of delivering or receiving care. View Glossary
State State The state where the project originates, or where the primary institution or organization is located. View Glossary
Last updated: March 14, 2024