Introduction: Currently, monitoring the airflow restriction in subglottic stenosis (SGS) requires in-person pulmonary function testing (PFTs). We aimed to assess the relationship between patient-performed and patient-reported peak flow meter (PFM) measurements with PFT measurements and Dyspnea Index (DI) scores as a tool for monitoring SGS disease progression at home.
Methods: Thirty-six SGS patients were prospectively recruited. Patients were given PFMs to report measurements from home. DI scores and PFT measurements were recorded at serial clinic visits. Data was analyzed to determine correlation between PFM measurements, DI scores and PFT measurements, and to determine how well those values predicted return to surgery for disease recurrence.
Results:PFM measurements had a “strong” correlation with the peak expiratory flow rate (PEFR), pearson’s correlation coefficient r = 0.74. PFM measurements had a “weak” correlation with DI scores, r= -0.21. The area under the curve (AUC) for the receiver operating characteristic curves was used to determine each measurement’s ability to predict return to surgery. AUC for PFM measurements, DI scores, and PEFR was 0.736, 0.921, and 0.791, respectively.
Conclusion: PFM measurements correlate strongly with PEFR measurements and have similar ability to predict surgery recurrence. PFM measurements and DI scores correlate weakly, likely due the DI being subjective. The DI best predicts surgery recurrence. The PFM provides a well-correlated surrogate for PEFR. Paired with the DI, PFMs provides a reliable longitudinal tool for assessing disease progression and need for surgery remotely. Reliable longitudinal monitoring for SGS patients may be feasible using these methods with telehealth visits.