Results Summary

What was the research about?

Comparative effectiveness research compares two or more treatments to see which one works better for certain patients. For example, research can see if medicines or stents work better for people with heart problems. Such research may include:

  • Observational studies. A research team studies what happens when patients and their clinicians choose the treatments. Traits, such as age or health, may affect patients’ treatment choices. These traits may also affect patients’ responses to treatments. It may be hard for the team to tell if a patient’s traits, the treatment, or a mix of the two affected how well the treatment worked.
  • Clinical trials. The team assigns patients to a treatment by chance. Traits may affect a patient’s ability to join a clinical trial.

In this study, the team tested ways to improve understanding of which treatment works better. First, the team compared different methods that account for things, such as patients’ traits, that could affect results of observational studies. In the second part of the study, the team worked on ways to use all available data with a method called meta-analysis. This method combines data from both study types.

What were the results?

The research team first looked at combined observational data for all patients who could and patients who couldn’t take part in clinical trials. Patients who could take part in clinical trials had, on average, better survival than patients who couldn’t take part in this type of study. The team found similar results about how treatments worked even when the team used different methods to account for things that could have affected the results.

The team found that meta-analysis results were more precise when the team combined data from groups of patients with data from other individual patients. Having more data improved precision.

What did the research team do?

The research team looked at medical data for patients with heart disease. These patients received medicine, stents, or open-heart surgery. Data came from 23,247 patients in the Duke Databank for Cardiovascular Disease. Data for 75,225 other patients came from published clinical trial and observational studies.

The team compared different statistical methods to account for things that could affect treatment results. The team also looked at data from people who could and who couldn’t take part in a published clinical trial for heart disease treatments. Some patients, for example, may have been too sick to take part. Finally, the team used new meta-analysis methods to combine data from multiple studies.

What were the limits of the study?

The research team used patient data from only one disease database that had some missing patient data. The methods the team used may not fully account for this problem.

Future research could look at how well these methods work in studies of other common health problems.

How can people use the results?

Researchers may want to use this study’s results for improving research methods for observational and meta-analysis studies.

Final Research Report

View this project's final research report

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:

  • The reviewers suggested that the researchers expand their limitations section to list the caveats to consider when applying the methods described in the report. The researchers expanded this section; for example, they added a caveat that a rigorous systematic review is a necessary starting point for methods involving evidence synthesis as well as value-of-information analyses.
  • The reviewers made several comments about the usability of this information for other researchers. The researchers expanded their discussion of the potential for study uptake, including information about real-world applications for these methods. The investigators also responded that their goal was to provide an example of how to apply these analytic methods to real-world data.
  • The reviewers lauded the researchers on their use of robust data sets to test their methods, but they also expressed concern that the study results from using these methods would be less reliable when applied to clinical conditions that are not as well documented in the literature as the one they used, coronary heart disease. The researchers responded by stating that the report attempts to demonstrate the feasibility of their approach for both emerging data with few publications and mature data with many publications in the literature.

Conflict of Interest Disclosures

Project Information

John B. Wong, MD
Tufts Medical Center
Integrating Causal Inference, Evidence Synthesis, and Research Prioritization Methods

Key Dates

September 2013
August 2018

Study Registration Information


Has Results
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
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: April 11, 2024