Results Summary

What was the research about?

Current medical guidelines recommend a type of medicine called ACE/ARBs to help patients live longer and protect their kidneys after a stroke. But studies show that rates of kidney disease have gone up at the same time that more people have been using this medicine. Additional research may help show if some patients shouldn’t take ACE/ARBs after a stroke.

In this study, the research team wanted to learn about the effects of taking ACE/ARBs for patients over age 65 who’ve had a stroke. The team reviewed Medicare claims for stroke survivors with and without chronic kidney disease, or CKD. CKD is a health problem in which the kidneys don’t remove waste from the blood well. The team compared patients in areas of the country with different rates of ACE/ARB use. The team looked at how many patients lived and how many had kidney problems over two years.

What were the results?

The study found that taking an ACE/ARB had different effects on survival for patients with and without CKD. Among patients without CKD, in areas where more patients took ACE/ARBs, more were alive after two years. Among patients with CKD in these areas, fewer were alive after two years. However, the study may not have had enough patients with CKD to say for sure what effect ACE/ARBs had on patient survival.

The amount of kidney problems over two years was similar for patients with or without CKD, regardless of how many people took ACE/ARBs in their area.

What did the research team do?

The research team looked at Medicare claims for 35,679 patients who had a stroke in 2010. All patients were over age 65, and 25 percent of these patients had CKD. Among patients with CKD, 60 percent were women, 79 percent were white, 14 percent were black, and 7 percent were other races. Among patients without CKD, 66 percent were women, 85 percent were white, 9 percent were black, and 6 percent were other races.

The research team compared the effects of taking an ACE/ARB on patients with and without CKD.

What were the limits of the study?

The study used the rates of ACE/ARB use from Medicare claims in 2010 in its analysis. Results may have been different if the study used rates from other years.

Future research could continue to explore whether ACE/ARB use should differ for patients with and without CKD. Future research could also focus on finding new methods that can detect the effect of ACE/ARB use in small groups of patients.

How can people use the results?

Researchers could look at this study when planning future research to examine the effects of ACE/ARB use among patients with and without CKD.

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. The comments and responses included the following:

  • Reviewers said the report is well written but difficult to read given the complex statistical terminology. In response, the researchers wrote the introduction to be more direct and contain less jargon.
  • Reviewers wondered how the study results can be used given that baseline characteristics of the patient population led to heterogeneous effects on multiple outcomes. The researchers agreed that their results cannot be easily generalized to other populations. The researchers emphasized that the goal of this methods study was to help show that investigators should not be looking for the effective treatment for a given population but the most effective mix of treatments for that population, such that a specific patient could not do better switching to a different treatment.

Conflict of Interest Disclosures

Project Information

John Brooks, PhD
University of South Carolina^
$941,733 *
10.25302/042020.ME.13036011
Understanding Treatment Effect Estimates When Treatment Effects Are Heterogeneous for More Than One Outcome

Key Dates

September 2013
February 2019
2013
2018

Study Registration Information

^John Brooks, PhD was affiliated with the University of Iowa when this project was funded.

Final Research Report

View this project's final research report.

Journal Articles

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Last updated: January 20, 2023