Results Summary

What was the research about?

When older adults have more than one long-term, or chronic, health problem, their health care may be hard to manage. Case managers—nurses or social workers who help manage a patient’s care—may be able to help. If their care is managed well, patients may be able to stay healthy and avoid going to the emergency room, or ER, or hospital.

In this study, the research team wanted to find out if having help from case managers kept patients with chronic health problems from going to the ER or hospital. The team compared patients with and without case managers.

What were the results?

A year after patients started getting help from case managers, patients with and without case managers didn’t differ in the number of ER visits or days they stayed in the hospital.

Who was in the study?

The study included electronic health record data from 5,768 patients receiving care at two Medicare accountable care organizations, or ACOs. ACOs are groups of healthcare providers, such as doctors and hospitals, who work together to provide patient care. Of these patients, 88 percent were White, and 12 percent were other races. The average age was 71, and 57 percent were women. More than 90 percent of patients had three or more chronic health problems, like diabetes.

What did the research team do?

The research team linked electronic health records from the ACOs with Medicare claims from January 2011 through September 2015. The team identified records for patients who were enrolled in a case management program. In the program, a nurse or social worker managed patients’ care. They also called patients twice a month to check on their needs.

Based on patient traits in the records, such as type of health problem, the research team matched patients who were enrolled in the case management program with patients who weren’t. Then they compared the patients who were in the program with those who weren’t. The team looked at the number of ER visits and days patients spent in the hospital one year after they started the program.

Patients, health system administrators, and doctors provided input on the study design and analysis.

What were the limits of the study?

The research team only looked at data from patients for one year after starting the program. Results may differ if the team looked at data for longer than one year.

Future research could look at other ways to support patients with chronic health problems.

How can people use the results?

ACOs can use these results when considering ways to help patients with chronic health problems manage their care.

How this project fits under PCORI’s Research Priorities
The PCORnet® Study 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.

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 asked for clarification on what patient sample the researchers  used in developing their predictive model, since the researchers stated that the predictive model was developed in a separate methodology project. The researchers clarified that while they developed the predictive model in another PCORI-funded project, the data came from the same patient sample as the current project.
  • The reviewers suggested that the researchers expand their discussion of the interaction between affordable care organizations and case management, asking whether there were aspects of the affordable care organizations that affected the quality of the care management services. The researchers responded that this study could not answer this question. In truth, they said that patients mostly wanted to find a key point person to help them navigate health services and did not really consider the relevance of the affordable care organization structure or of being part of a large health system. 
  • The reviewers suggested that the report’s conclusions overstated the importance of the social work case management intervention given the results of the project, which did not demonstrate significant differences between groups based on availability of the intervention. The researchers revised the conclusions to instead suggest that patients viewed social work as important for patient engagement in their health care. The researchers also noted in their response to reviewers that a finding of no difference was not the same as no value, since patients and providers viewed the case management intervention as being of high value.
  • One reviewer questioned the threshold the researchers applied to patient characteristics they used to match case management participants to controls. In this study, the researchers allowed matching covariates to vary up to 25 percent between the case and the control, but the reviewer noted that a more common threshold was 10 percent variation between case and control. The researchers pointed out their sample size was not large enough for a 10 percent threshold to be possible.  In addition, the researchers noted that even in randomized samples there are likely to be a few covariates that vary 25 percent or more. The researchers also noted that in their analyses, they accounted for potential confounding from covariates that varied to this level.

Conflict of Interest Disclosures

Project Information

Maureen A. Smith, MD, PhD, MPH
University of Wisconsin-Madison
Variation in Case Management Programs and Their Effectiveness in Managing High-Risk Patients for Medicare ACOs

Key Dates

June 2016
January 2023

Study Registration Information


Has Results
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Last updated: March 14, 2024