The emerging association between bronchiectasis and systemic sclerosis: assessing prevalence and potential causality

Background Bronchiectasis has been observed in association with systemic sclerosis (SSc). Theorised aetiology includes aspiration related to oesophageal dysmotility, immunosuppressant medication use and the direct effect of collagen deposition on airway calibre. Aims To detail bronchiectasis prevalence in an SSc population who have had a high-resolution computed tomography (HRCT) of the thorax. We assessed whether oesophageal dysmotility, demographic variables, SSc duration or subclass were associated with bronchiectasis. Methods Participants in the Australian Scleroderma Cohort Study (ASCS) with a HRCT were included. The ASCS provided demographic and clinical data. HRCT studies were reviewed for bronchiectasis, oesophageal dilatation and interstitial lung disease (ILD). Traction bronchiectasis associated with ILD was recorded as a separate entity to bronchiectasis. Oesophageal dysmotility was defined by symptoms and/or oesophageal dilatation. Results Of the 256 participants, 16.4% (n = 42) had bronchiectasis. Logistic regression analysis revealed no significant association between bronchiectasis and oesophageal dysmotility (observed in 95.7%), any demographic variable, SSc duration or subclass. A negative association between bronchiectasis and ILD was observed (P = 0.009; odds ratio 0.322; 95% confidence intervals 0.137-0.756). Conclusion Those with SSc appear to have an increased risk for bronchiectasis. Since bronchiectasis was not more frequent in participants with a longer duration of SSc, we hypothesise that its development is not related to immunosuppression alone. Oesophageal dysmotility was almost universal in our population such that its effect on bronchiectasis development could not be concluded. A negative association between bronchiectasis and ILD reflects that bronchiectasis occurring alongside ILD was recorded as a separate entity.