Predicting mortality in non-cystic fibrosis bronchiectasis patients using distance-saturation product

BACKGROUND: The bronchiectasis severity index (BSI) and FACED score are currently used in predicting outcomes of non-cystic fibrosis bronchiectasis (NCFB). Distance-saturation product (DSP), the product of distance walked, and lowest oxygen saturation during the 6-min walk test showed strong predictive power of mortality in non-CF bronchiectasis patients. This study aimed to compare the efficacy of these scores and DSP in predicting mortality. METHODS AND PATIENTS: Our retrospective study included NCFB patients from January 2004 to December 2017. We recorded the basic data, pulmonary function, radiologic studies, sputum culture results, acute exacerbations (AE), emergency department (ED) visits, hospitalization, and mortality. RESULTS: A total 130 NCFB patients were analysed. The mean BSI score, FACED score, and DSP were 8.8 ± 4.9, 3.4 ± 1.7, and 413.1 ± 101.5 m%, respectively. BSI and FACED scores had comparable predictive power for AE (p=.011; p=.010, respectively). The BSI score demonstrated a significant correlation with ED visits (p=.0003). There were 12 deaths. Patients were stratified using a DSP cut-off value of 345 m% according to the best area under receiver operator characteristic curve (AUC) value in mortality. DSP was not correlated with AE and ED visits. BSI, FACED scores, and DSP demonstrated statistically significant correlations with hospitalization (p<.0001; p<.0001; p=.0007, respectively). The AUC for overall mortality was similar for BSI, FACED score, and DSP (0.80 versus 0.85, p=.491; 0.85 versus 0.83, p=.831). CONCLUSION: DSP had comparable predictive power for mortality as the well-validated BSI and FACED scores and is relatively easy to use in clinical practice. KEY MESSAGE: Distance-saturation product (DSP) comprised with the product of distance walked, and lowest oxygen saturation during the 6-min walk test, which is common used in clinical practice. DSP demonstrated strong and comparable predictive power of mortality as the well-validated BSI and FACED scores in non-CF bronchiectasis patients.