Treatable traits in bronchiectasis
| Diagnostic criteria | Treatment | Expected benefits of treatment | |
| Pulmonary | |||
| Infection# | Clinical features Sputum characteristics Inflammatory markers Sputum culture | Airway clearance Prompt treatment of exacerbations Long-term oral or inhaled antibiotics | Reduce exacerbations Improve QoL |
| Chronic Pseudomonas infection | ≥2 culture isolates at least 3 months apart in 1 year | Long-term inhaled antibiotics Long-term macrolides Airway clearance Eradication at first isolation | Reduce exacerbations Improve QoL Slow lung function decline Prevent chronic infection |
| Mucus hypersecretion | Volume Colour of sputum | Airway clearance Airway adjunct devices Mucoactive drugs Anti-inflammatories | Reduce sputum volume Reduce viscosity/increase ease of expectoration |
| Mucus plugging | Clinical features CT scan | Airway clearance Mucoactive drugs Nebulised saline Anti-inflammatories | Reduce sputum volume Reduce viscosity/increase ease of expectoration |
| Airflow obstruction | FEV1/FVC <LLN Fixed ratio spirometry GLI equations, air trapping or increased airway resistance | Bronchodilators Smoking cessation Exercise | Improved exercise capacity and functional status |
| Asthma | Bronchodilator reversibility Peak expiratory flow variability Elevated sputum or blood eosinophils | ICS Systemic corticosteroids Bronchodilator Leukotriene receptor antagonists Monoclonal antibody anti-IL-5, anti-IgE | Reduce exacerbations |
| Eosinophilia | Elevated sputum or blood eosinophils Exclude other causes of eosinophilia | ICS Systemic corticosteroids Treatment for underlying cause | Improve QoL and treatment response |
| NTM pulmonary disease¶ | Positive culture and clinical/radiological findings | Long-term antibiotic | Improve QoL and achieve remission |
| Aspergillus sensitisation | Elevated specific IgE/prick test positive | ICS Systemic corticosteroids Antifungals | Reduce exacerbations Reduce sputum production Improved QoL |
| Bronchial hyperreactivity | Challenge tests | ICS | Reduce exacerbations |
| Cough hypersensitivity | Clinical features Search other potential extrapulmonary causes Capsaicin cough challenge | Antitussive Chest physiotherapy | Improve QoL |
| Respiratory insufficiency | PaO2 <55 mmHg PaCO2 >45 mmHg | Long-term oxygen and/or noninvasive ventilation | Improve QoL Improve survival |
| Aetiological | |||
| Primary immunodeficiencies | Serum immunoglobulins levels Specific antibody levels | Refer to immunology specialist Immunoglobulin replacement | Improve outcome Improve QoL Prevent lung damage |
| CF | Clinical features Sweat chloride testing, CFTR genetic analysis and/or CFTR physiological testing | Refer to CF clinic CFTR modulators DNAse | Improve outcome Improve QoL Prevent lung damage |
| PCD | Clinical features+ Nasal NO assay Electron microscopy ciliary structure analysis or video recording ciliary function analysis Genetic testing | Genetic counselling Intensive airway clearance Management of upper airway symptoms | Improve outcome Improve QoL Prevent lung damage |
| ABPA¶ | Raised specific IgE and/or positive prick skin test to fungi, raised total IgE Other: eosinophilia, radiological features, raised specific IgG/precipitating antibodies against fungi | Systemic corticosteroids and/or antifungals Monoclonal antibody anti-IgE ICS | Improve outcome Improve QoL Prevent lung damage |
| CTD | Clinical features Serum antibodies | Refer to rheumatologist Immunosuppressors | Improve outcome Improve QoL Prevent lung damage |
| IBD | Clinical features Serological markers Anatomopathological findings on gut biopsy | Refer to gastroenterologist Immunosuppressors Surgery | Improve outcome Improve QoL Prevent lung damage |
| Extrapulmonary (comorbidities) | |||
| Depression/anxiety | Questionnaires Psychologist/liaison Psychiatrist assessment | Anxiety management Breathing retraining Cognitive behavioural therapy Pharmacotherapy Support groups | Improve QoL |
| Obesity/underweight | BMI | Nutritional evaluation Regular physical activity | Improve QoL and outcome |
| GORD | Clinical features Gastric endoscopy pH monitoring | Proton pump inhibitor H2-antagonist Surgery (fundoplication) | Improve QoL |
| Cardiovascular disease | Clinical features Electrocardiogram Echocardiogram BNP Stress testing | ACE inhibitors Diuretics β-blockers Revascularisation Refer to cardiologist | Improve QoL and outcome |
| Rhinosinusitis | Clinical features Imaging | Nasal steroids Leukotriene receptor antagonists Antihistamines Immunotherapy Surgery | Improve QoL |
| Iron deficiency anaemia | Full blood count Reticulocyte count Serum iron tests Exclude other causes | Oral iron supplements Treatment of underlying cause | Improve QoL and exercise capacity |
| Environment and lifestyle | |||
| Smoking | Patient reported Exhaled carbon monoxide | Tobacco cessation support Nicotine replacement Antidepressants | Improve QoL, lung function, exercise capacity, response to treatment |
| Lack of exercise/sedentarism | Cardiopulmonary exercise testing 6-min walk test | Exercise regularly Pulmonary rehabilitation Prescribed exercise programmes | Improve QoL and outcome |
| Adherence | Prescription refill rate Patient feedback | Education Written instructions Self-management | Improve outcome |
| Exposure to air pollution | PM10 and NO2 concentrations | Reduce exposure | Reduce exacerbations |
Some of the most common traits observed in clinical studies have been listed, but this list is not comprehensive. A different set of treatable traits may be applicable to children with bronchiectasis to include issues of growth and development. CT: computed tomography; FVC: forced vital capacity; LLN: lower limit of normal; GLI: Global Lung Function Initiative; QoL: quality of life; PaO2: arterial oxygen tension; PaCO2: arterial carbon dioxide tension; CTD: connective tissue disease; IBD: inflammatory bowel disease; GORD: gastro-oesophageal reflux disease; BNP: brain natriuretic peptide; ACE: angiotensin converting enzyme; PM10: particulate matter with a diameter smaller than 10 μm. #: the presence of airway infection itself may not be a treatable trait as such since better measures are required to differentiate infection from “colonisation” where the trait is not contributing directly to disease outcome. Additional measures such as bacterial load or microbiota characterisation may be needed to fully operationalise this trait. ¶: could be aetiological or a complication of disease. +: recurrent upper and lower respiratory tract infections; recurrent otitis in childhood; infertility; and laterality disorders. Reproduced from [5] with permission.