Multimorbidity in bronchiectasis: a systematic scoping review.

Introduction: Multimorbidity, the coexistence of two or more chronic conditions, has been extensively studied in certain disease states. Bronchiectasis aetiology is complex and multimorbidity is insufficiently understood. We performed a scoping review, summarising the existing literature and identifying deficits. Method: A literature search of the electronic databases PubMed, CINAHL and EMBASE was conducted following PRISMA guidelines. Observational, interventional, qualitative, randomised control trials and systematic reviews were included. The main objective was to identify prevalence, prognosis, symptoms, quality of life and management in bronchiectasis multimorbidity. Key findings were analysed descriptively. Results: 40 studies (200 567 patients) met the inclusion criteria, the majority (68%) being cohort studies. Study size ranged from 25 to 57 576 patients, with mean age 30-69 years. 70% of studies investigated the prognosis of comorbidities and 68% prevalence; 70% analysed multiple comorbidities in bronchiectasis. The most frequent comorbid diseases evaluated were COPD (58%), cardiovascular disease (53%) and asthma (40%). COPD and hypertension were the most prevalent conditions (pooled mean 35% and 34% respectively). Multimorbidity was associated with increased mortality, exacerbations and hospitalisation rates. It had a negative impact on lung function. Mortality increased in the following comorbidities: COPD, gastro-oesophageal reflux disease and rheumatoid arthritis. Conclusion: Bronchiectasis multimorbidity is common. Research focuses on a few key aspects and favoured comorbidities (