Bronchiectasis (BC) is a chronic respiratory disease characterized by abnormal and irreversible dilatation of the airways, associated with a vicious cycle of compromised host defenses, inflammation, chronic colonization with bacteria and recurrent infection with progressive bronchial lesion.1,2 Traditionally, bronchiectasis is classified as cystic fibrosis-related bronchiectasis and non-cystic fibrosis bronchiectasis (NCFB). Cystic fibrosis-related bronchiectasis affects a small homogeneous population of patients, where respiratory disease is the main predictor of mortality,3 whereas NCFB affects a heterogeneous population of patients with diverse etiologies.3 These may result from various hereditary or acquired local or systemic diseases, and often the etiological diagnosis is not defined even after exhaustive assessment.1 The clinical course of this pathology is unpredictable. While the usual disease progression is slow, cases involving faster disease progression have been reported.4 Bronchiectasis is also associated with chronic sputum, multiple exacerbations and dyspnea, which progressively worsened quality of life5,6 and lung function (annual loss of about 50ml in FEV1),7 with a negative impact on the number of hospitalizations, health costs and mortality.8

As it is a chronic and progressive disease, the establishment of management strategies is essential for the control of this pathology. Several individual variables were used to assess the severity of NCFB, but the prognosis cannot be adequately assessed through a single variable analysis.

Recently, two multidimensional severity indexes were developed: the FACED score and the Bronchiectasis Severity Index (BSI). The FACED score corresponds to a scale that evaluates the severity and prognosis of NCFB through the analysis of five parameters/variables: functional (FEV1% predicted), physiological (age), microbiological (chronic colonization by Pseudomonas aeruginosa), radiological (number of lobes affected) and clinician (degree of dyspnea, evaluated by the mMRC scale).9 The BSI corresponds to a scale that evaluates the severity and prognosis of NCFB by analyzing nine parameters/variables: age, body mass index (BMI), FEV1% predicted, hospitalization and exacerbations before study, degree of dyspnea, chronic colonization by P. aeruginosa and other microorganisms and radiological extension of the disease.2

The characteristics of the patients included in the study are described in Table 1. In terms of the etiology of NCFB, data analysis revealed that 24 patients (60%) were idiopathic, 8 (20%) post-infectious, 5 (12.5%) with sequelae of pulmonary tuberculosis and 3 patients (5%) with primary immunodeficiencies.

The FACED and BSI score variables are shown in Tables 2 and 3 (respectively). After applying the FACED score, 20 patients (50%) were classified as mild BC, 15 (37.5%) as moderate and 5 (12.5%) as severe BC. When using the BSI score, 13 patients (32.5%) were classified as low BSI, 13 (32.5%) as intermediate BSI and 14 (35%) as high BSI.

Statistical analysis was also performed to assess how the scores match in predicting BC severity (% conditioned by each of the scores). As demonstrated in Table 4, 30.8% of patients with intermediate BSI were found to have mild BC by FACED and 78.6% of patients with high BSI had mild or moderate BC by FACED. Moreover, 40% of patients with mild BC by FACED had at least moderate BSI and about 46.7% of patients with moderated BC by FACED had elevated BSI.

A weak but statistically significant association between FACED and BSI scores was also detected using Fisher's exact test (p=0.004) and tau-b de Kendall (0.469; p=0.001). Upon applying the Wilcoxon test for paired samples, it was found that the two scales were significantly different (p=0.004), with the BSI scale showing the highest scores (Table 4). With this test, a 55.0% agreement between the two scales (22 ties/40=0.55) was also detected (Table 4). Similarly, using the Cohen's Kappa test (κ=0.330, p=0.002) a 55.0% agreement between the two scales was also found.

Currently, the medical community faces two major challenges in the management of bronchiectasis: (1) identifying patients with a high symptom burden, those at risk of frequent exacerbations or rapid lung function decline, who may benefit from aggressive treatment at an early stage of the disease, in order to reduce the associated complications as well as allow a closer follow-up at a specialized center and (2) identifying low-risk patients, who could be suitable for non-specialist follow-up or simpler treatment regimes, to reduce health costs and improve patient satisfaction.

At present, there are two scales that can be used to assess the severity and the prognosis of the NCFB: FACED and BSI. Both scales have clear advantages and disadvantages. The FACED score is easy to obtain, calculate and interpret as it incorporates five dichotomous variables. The BSI is a relatively more complex scale since it incorporates nine variables with different values for each. Both stratify patients into severity risk categories in order to predict the likelihood of mortality. Moreover, these two scales have also different objectives: while the FACED was developed specifically to predict the likelihood of mortality in five year follow-up of NCFB of any etiology, thus providing a quick assessment of the initial severity, the BSI was developed to predict mortality, severe exacerbations requiring hospitalization, frequency of exacerbations, and quality of life.

As a multidimensional and heterogeneity disease, bronchiectasis is not a disease of which impact is primarily measured in terms of mortality. In this context, although the FACED score has demonstrated a great prognostic capacity in the evaluation of bronchiectasis, it does not include the number or severity of exacerbations so, in order to evaluate the predictive capacity of exacerbations and mortality, a new scale, E-FACED,17 was recently constructed and validated. This score significantly increases the FACED capacity to predict future yearly exacerbations while maintaining the score's simplicity and prognostic capacity for death.17

A observational prospective study by McDonnell et al. (2016), developed to compare the predictive utility of BSI and FACED in assessing clinically relevant disease outcomes across seven European cohorts with 1612 patients, demonstrated that both tools accurately predict mortality in bronchiectasis, but that the BSI is superior to FACED in predicting multiple clinically useful outcomes including hospital admissions, exacerbations, quality of life, respiratory symptoms, exercise capacity and lung function decline.18

A retrospective study by Ellis et al. (2016), developed to assess the ability of these scores to predict long-term mortality in a cohort of 91 patients, showed that both scoring systems had similar predictive power for 5-year mortality.19 In addition, both scores were able to predict 15-year mortality providing further validation for the prediction of mortality in bronchiectasis and demonstrating their utility over a longer period than originally described. However, the predictive capacity of FACED was superior for 15-year mortality.19

In our study, we found a small but significant association between the two scales, since there is a tendency for patients to be classified with a higher BSI relative to the FACED. This could be explained by the fact that the BSI (and not FACED) assesses parameters including BMI, hospitalization and exacerbations before study, chronic colonization by other microorganisms and development of cystic bronchiectasis. The fact that BSI score performs a different stratification of the parameters age, dyspnea degree and FEV1% predicted can also be a contributing factor.

This study has limitations that must be mentioned. The limited number of patients, the fact that these scores applied to the last appointment and there have been no deaths until now, did not provide for a more exhaustive analyses, specifically the capacity of these scores to predict mortality. Despite these limitations, our results are similar to results from other studies, which show that the BSI provides an accurate assessment of disease severity enabling decision-making in terms of identifying high-risk patients who may benefit from aggressive treatment and low-risk patients who could receive non-specialist follow-up or simpler treatment regimes. However, our results do not prove that implementation of the BSI or FACED may improve clinical outcomes and further studies are needed to determine how these scales may have an impact on clinical practice.

As a multidimensional pathology, the severity and prognosis of NCFB cannot be adequately assessed through a single variable analysis. Thus, although different, the FACED score and BSI correspond to validated multidimensional indices, which provide an accurate assessment of the severity and prognosis of this pathology. In our study, we found a small but significant association between the two scales, since there is a tendency for patients to be classified with higher BSI relative to the FACED. The currently available literature shows that the BSI is superior to FACED in predicting multiple clinically useful outcomes including hospital admissions, exacerbations, quality of life, respiratory symptoms, exercise capacity and lung function decline, providing a clinically relevant assessment of the severity of the disease.

The authors have no conflicts of interest to declare.