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.
Professional Abstract
Objective
To compare the effectiveness of three treatments for idiopathic subglottic stenosis (iSGS) on delaying time to recurrence and improving patient-reported outcomes
Study Design
| Design Elements | Description |
|---|---|
| Design | Observational: cohort study |
| Population | 810 patients with iSGS |
| Interventions/ Comparators |
|
| Outcomes |
Primary: time to recurrence Secondary: breathing, speaking, and swallowing ability; global quality of life |
| Timeframe | 3-year follow-up for primary outcome |
iSGS is a rare illness in which the trachea narrows for no known reason. The illness is recurrent and can cause severe difficulties with breathing, speaking, and swallowing. iSGS most commonly affects white women. This prospective cohort study compared the effectiveness of three common treatments for iSGS on time to recurrence, or how long after the procedure it takes for patients to experience recurrent stenosis and the need to undergo repeat surgical treatment.
Patients underwent one of three initial treatments for iSGS:
- Endoscopic dilation. Doctors access the patient’s trachea through the mouth and dilate, or stretch, the narrowed portion of the airway using surgical instruments or inflatable balloons.
- Endoscopic resection with long-term medical therapy. Doctors access the patient’s trachea through the mouth and use a surgical laser to resect a portion of the airway scar. After this procedure, patients require long-term medication use.
- Open cricotracheal resection. Doctors use an external incision to remove the damaged section of trachea and reconstruct the airway.
This study included 810 patients from 40 clinics in the United States, Australia, France, Iceland, Norway, and the United Kingdom. Of these patients, 97% were white, 98% were female, and the median age was 50. Prior to the study, patients had no history of surgical treatment for iSGS.
Throughout three years, patients were followed every three months to determine if they needed another surgical procedure. Every six months, researchers administered surveys to patients about their iSGS symptoms to compare their breathing, speaking, and swallowing and overall quality of life. These outcomes were assessed up to one year following treatment.
Patients with iSGS, iSGS providers, and regional patient advocates worked with researchers to plan and conduct the study, recruit participants, and distribute study results.
Results
Within the three-year timeframe, 185 patients, or 23%, required a subsequent procedure (mean follow-up 1.4 years). Open tracheal resection had the lowest recurrence rate (1%), followed by endoscopic resection (12%) and endoscopic dilation (28%). Differences across recurrence rates were significant (all p<0.01) and clinically important.
At one year patients who received endoscopic dilation reported worse breathing ability (p<0.001) and poorer quality of life (p=0.015) than patients who received the other two treatments. Patients who received open cricotracheal resection reported worse speaking ability than patients receiving the other two treatments (p<0.001). Patient-reported swallowing ability did not differ across the three treatments.
Limitations
Lack of a randomized study design limits the ability to draw conclusions from the study results. For example, surgeons may be better trained in one treatment than another, which could have influenced outcomes rather than the type of treatment itself.
Conclusions and Relevance
In this study, open cricotracheal resection had the lowest rate of iSGS recurrence but was associated with worse speaking ability. Endoscopic resection with long-term medical therapy had a lower recurrence rate than endoscopic dilation, with less impact on speaking ability than open tracheal resection.
Future Research Needs
Future research could follow patients for longer than three years to determine if the relative effectiveness of the three treatments changes over time.
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.