Disease homogeneity and treatment heterogeneity in idiopathic subglottic stenosis

Abstract

Objectives/hypothesis: Idiopathic subglottic stenosis (iSGS) is a rare and potentially life-threatening disease marked by recurrent and progressive airway obstruction frequently requiring repeated surgery to stabilize the airway. Unknown etiology and low disease prevalence have limited the ability to characterize the natural history of iSGS and resulted in variability in surgical management. It is uncertain how this variation relates to clinical outcomes.

Study design: Medical record abstraction.

Methods: Utilizing an international, multi-institutional collaborative, we collected retrospective data on patient characteristics, treatment, and clinical outcomes. We investigated variation between and within open and endoscopic treatment approaches and assessed therapeutic outcomes; specifically, disease recurrence and need for tracheostomy at last follow-up.

Results: Strikingly, 479 iSGS patients across 10 participating centers were nearly exclusively female (98%, 95% confidence interval [CI], 96.1-99.6), Caucasian (95%, 95% CI, 92.2-98.8), and otherwise healthy (mean age-adjusted Charlson Comorbidity Index 1.5; 95% CI, 1.44-1.69). The patients presented at a mean age of 50 years (95% CI, 48.8-51.1). A total of 80.2% were managed endoscopically, whereas 19.8% underwent open reconstruction. Endoscopic surgery had a significantly higher rate of disease recurrence than the open approach (chi(2) = 4.09, P = 0.043). Tracheostomy was avoided in 97% of patients irrespective of surgical approach (95% CI, 94.5-99.8). Interestingly, there were outliers in rates of disease recurrence between centers using similar treatment approaches.

Conclusion: Idiopathic subglottic stenosis patients are surprisingly homogeneous. The heterogeneity of treatment approaches and the observed outliers in disease recurrence rates between centers raises the potential for improved clinical outcomes through a detailed understanding of the processes of care.

Level of evidence: 4. Laryngoscope, 126:1390-1396, 2016.

Keywords: Idiopathic subglottic stenosis; comparative effectiveness; cricotracheal; dilation; tracheostomy.

Fig. 1.

Variation of theraputic approach at each participating site. (A) Percentage of iSGS patients treated endoscopically (green bars) and open (red bars) at each participating center. (B) Number of endoscopic procedures prior to open reconstruction (red bar indicating mean) at participating centers offering open surgery. endo = endoscopic; iSGS = idiopathic subglottic stenosis.

Fig. 2.

Disease recurrence in open and endoscopic therapy. (A) Kaplan Myer curve depicting the percentage of patients avoiding disease recurrence after their initial procedure at 10 pooled centers. (B) When the subgroup of patients that underwent endoscopic surgery was stratified by center, there was one significant positive outlier (site 3; P < 0.001). (C) When the subgroup of patients that underwent open surgery was stratified by center, there were two significant positive outliers (sites 1 and 8; P < 0.001).

Fig. 3.

Relationship of surgical volume to outcome. There was no relationship between outcome and a center’s endoscopic surgical volume (Spearman r = 0.16, P = 0.64). In contrast, open surgery did show a significant negative correlation between surgical volume and recurrence rate (Spearman r = −0.91, P < 0.0001); that is, higher volume was related to less recurrence.