Results Summary

What was the research about?

Type 2 diabetes is a health problem that causes blood sugar levels to rise. Diabetes causes many health problems and can be hard to manage. Clinicians, like doctors and nurses, may need to spend extra time planning care for these patients. This kind of planning, called chronic care management, or CCM, may include working with other doctors and following up with patients online or by phone outside of regular office visits. In 2015, Medicare started to pay clinicians for CCM services.

In this study, the research team wanted to learn whether CCM leads to better health outcomes for patients with diabetes. They compared health records for patients who received CCM with patients who didn’t receive it.

What were the results?

Compared with the group of patients who didn’t receive CCM, the group of patients who received CCM had lower:

  • Average blood sugar levels
  • Average body weight
  • Average blood pressure
  • Average cholesterol
  • Percentage of patients with overweight
  • Percentage of patients with hypertension

The group of patients who received CCM also had an increase in doctor’s office visits and a decrease in hospital and emergency room visits. The two groups didn’t differ in the percentage of patients who had serious heart problems, like a heart attack or stroke.

Who was in the study?

The study included health records from 22,347 patients with type 2 diabetes. All received care at one of three health systems in Louisiana between January 2013 and February 2020. Of these patients, 39 percent were Black, and 3 percent were Hispanic or Latino. The average age was 72, and 55 percent were women.

What did the research team do?

The research team looked at health records for patients to see if they received CCM. They then looked at patients’ health records for the two years before and after they received CCM. The team compared this group of patients to a group of patients with similar traits who didn’t receive CCM.

Patients with type 2 diabetes, doctors, and insurers helped design the study.

What were the limits of the study?

Because of the study design, it isn’t possible to know for sure if the changes in patient health happened because of CCM or something else that occurred at the same time. The study included patients from three health systems in Louisiana. Results may differ for patients in other states.

Future research could look at the impact of CCM in other states.

How can people use the results?

Policy makers can use the results to understand how CCM affects patient health.

How this project fits under PCORI’s Research Priorities
The research reported in this results summary was conducted using PCORnet®, the National Patient-Centered Clinical Research Network. PCORnet® is intended to improve the nation’s capacity to conduct health research, particularly comparative effectiveness research (CER), efficiently by creating a large, highly representative network for conducting clinical outcomes research. PCORnet® has been developed with funding from the Patient-Centered Outcomes Research Institute® (PCORI®).

Final Research Report

View this project's final research report.

Journal Citations

Related Journal Citations

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 expressed concern that the multiple outcomes, including several cut-points for glycated hemoglobin (also known as hemoglobin A1c or A1c), would lead to significant outcomes that could be attributed to chance. The reviewers noted that the study protocol focused on fewer comparisons and asked why the additional cut-points were added and whether these were predetermined or added post-hoc. The researchers clarified that their primary outcome was the measure of A1c under 7 percent, but that they had included post-hoc measurement at 9 percent or 8 percent, as well as several cut-points for the size of the difference in A1c from baseline to follow-up.
  • The reviewers questioned one of the results of the study, indicating that there was a substantial increase in outpatient visits that were not focused on care management in the patients enrolled in the care management program, because this result did not seem to be consistent between electronic health records and claims data. The researchers acknowledged that this finding was not consistent across databases and this difference was probably attributable to how non-case management visits were documented.
  • The reviewers also asked the researchers to clarify some of the methods that were used and how some of the analyses were performed, particularly with variable follow-up on the outcome measures. The researchers explained their methods further and particularly how they accounted for differences in the follow-up period, standardizing the number of months for follow-up if the outcome variable was sensitive to the time between baseline and follow-up.
  • The reviewers commented on the application of the RE-AIM framework (Reach, Effectiveness, Adoption, Implementation, Maintenance) to this research and especially that the researchers did not seem to apply this framework in the discussion of study results. The researchers added a table to the discussion that synthesized the results into each of the RE-AIM periods.
  • The reviewers questioned the researchers’ conclusion that the modest decreases in mean A1c were clinically meaningful given that this was based on survey results in a paper that concluded the opposite. The researchers added text to the report indicating that the modest differences are probably not clinically meaningful, but it is encouraging that patients with higher A1c at baseline showed the greatest reduction by follow-up.

Conflict of Interest Disclosures

Project Information

Lizheng Shi, PhD, MA, MSPharm
Tulane University
Natural Experiments of the Impact of Population-Targeted Health Policies to Prevent Diabetes and Its Complications

Key Dates

January 2016
November 2022

Study Registration Information


Has Results
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
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Last updated: October 18, 2023