Systemic sclerosis and risk of bronchiectasis: a nationwide longitudinal cohort study

Background The association between systemic sclerosis and the development of bronchiectasis is unclear. This study aimed to compare the risk of bronchiectasis between individuals with systemic sclerosis and those without using a nationwide longitudinal dataset. Methods Using the Korean National Health Insurance Service dataset between 2010 and 2017, we identified 4845 individuals aged [greater than or equal to] 20 years with systemic sclerosis and 24,225 without systemic sclerosis who were matched 1:5 by age and sex. They were followed up until the date of a bronchiectasis diagnosis, death, or December 31, 2019, whichever came first. Results During a median follow-up period of 6.0 (interquartile range, 3.2-8.7) years, 5.3% of the systemic sclerosis cohort and 1.9% of the matched cohort developed bronchiectasis, with incidence rates of 9.99 and 3.23 per 1000 person-years, respectively. Even after adjusting for potential confounders, the risk of incident bronchiectasis was significantly higher in the systemic sclerosis cohort than in the matched cohort (adjusted hazard ratio 2.63, 95% confidence interval 2.22-3.12). A subgroup analysis of individuals with systemic sclerosis revealed that the risk of incident bronchiectasis was notably higher in younger individuals aged 20-39 years (P for interaction = 0.048) and in those without other coexisting connective tissue diseases (P for interaction = 0.006) than in their counterparts. Conclusions The risk of incident bronchiectasis is higher in individuals with systemic sclerosis than those without. Bronchiectasis should be considered one of the pulmonary manifestations related to systemic sclerosis. Keywords: Systemic sclerosis, Bronchiectasis, Epidemiology, Risk