Results Summary

What was the research about?

Idiopathic subglottic stenosis, or iSGS, is a rare disease that is most common among white women. With this disease, the trachea, or windpipe, narrows for unknown reasons. iSGS may affect quality of life by making it difficult for patients to breathe and by limiting daily activities such as talking and swallowing. iSGS can be treated but may come back after treatment. Having information about how different treatments for iSGS compare with each other can help patients and their doctors choose the treatment that works best for the patients.

In this study, the research team compared three common treatments for iSGS:

  • Endoscopic dilation. Doctors go through the patient’s mouth and use a balloon or other tool to stretch open the trachea.
  • Endoscopic resection with long-term medicine use. Doctors go through the patient’s mouth and use a laser to remove the blockage in the trachea. After the treatment, patients require long-term medicine use.
  • Cricotracheal resection. Doctors cut open the front of the neck to remove the blockage in the trachea and then rebuild the airway.

Patients decided, with their doctors, which of the three treatments to get. Following treatment, the research team tracked symptoms to see if and how quickly iSGS symptoms came back.

What were the results?

Within three years of treatment, 23 percent of patients needed another treatment because symptoms of iSGS came back. Patients who received cricotracheal resection had the lowest rate of needing more treatments. Additional treatments were needed in

  • 1 percent of patients who received cricotracheal resection
  • 12 percent of patients who received endoscopic resection with long-term medicine use
  • 28 percent of patients who received endoscopic dilation

After one year

  • Patients who received endoscopic dilation reported worse breathing ability and quality of life than patients who received the other two treatments.
  • Patients who received a cricotracheal resection reported worse speaking ability than patients who received the other two treatments.
  • Swallowing ability was similar for the three treatments.

Who was in the study?

This study included 810 patients from 40 clinics in the United States, Australia, France, Iceland, Norway, and the United Kingdom. Of these patients, 97 percent were white. The median age was 50, and 98 percent were women. Before the study, patients hadn’t received treatment for iSGS.

What did the research team do?

The research team looked at patients’ medical records and surveyed patients for three years. Every three months, the team looked at whether patients needed another treatment. Every six months, the team asked patients about quality of life and problems with breathing, speaking, and swallowing.

Patients with iSGS and clinicians treating iSGS were members of the research team and were involved throughout the study.

What were the limits of the study?

The research team didn’t assign patients to a treatment by chance. Therefore, the team can’t be sure that the results were from the treatments or were caused by something the team didn’t study. For example, some doctors might be better trained in one treatment than another, which could affect how well patients do after treatment.

Future studies could track patients for longer than three years to learn if the treatment effects continue over time.

How can people use the results?

Doctors and patients can use the results when considering treatment decisions for iSGS.

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. The comments and responses included the following:

  • Reviewers asked for greater clarity about the requirements for inclusion in the study. Specifically, it seemed that researchers included only participants with complete baseline data in the sample, and the index procedure for subglottic stenosis may have occurred prior to the beginning of the study. The researchers confirmed both of these assumptions. They updated the abstract and the methods section to clarify that the study included both newly diagnosed and previously treated patients. The researchers also clarified that the final analysis only included patients who had completed baseline surveys and if researchers had documention of the patients’ initial procedures, some of which predated the study.
  • Reviewers expressed concern that requiring complete baseline information may have biased the sample since many patients reportedly were not able to complete this information at their index visits. The researchers conducted a sensitivity analysis comparing participants with complete baseline information to those patients without complete information. The researchers found no differences between groups.
  • Reviewers asked whether the study accounted for unmeasured effects of variables like surgeon, surgery center, or medication on the treatment outcomes. The researchers said they considered conducting analyses to disentangle these potential confounders but realized that the analyses would not be possible given the amount of potential missing data. Instead, the researchers discussed the limitations related to these potential confounders in the report’s discussion.
  • Reviewers asked for more information on the possibility of competing interests in the study team, given that the study suggested that one procedure performed at one institution is superior to others. The researchers said that none of the investigators had financial relationships relevant to the analysis and that they performed the biostatistical analysis independently.

Conflict of Interest Disclosures

Project Information

Alexander Gelbard, MD
Vanderbilt University Medical Center
Treatment Alternatives in Adult Rare Disease; Assessment of Options in Idiopathic Subglottic Stenosis

Key Dates

April 2015
May 2019

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
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: April 11, 2024