Impact of hyponatraemia during exacerbation on clinical outcomes in patients with bronchiectasis

<sec><title>INTRODUCTION</title>Hyponatraemia is associated with morbidity and mortality among various medical disorders. Evidence on the association between hyponatraemia at the time of exacerbation and the prognosis in patients with bronchiectasis is lacking.</sec><sec><title>METHODS</title>This was a single-centre retrospective study. We included all bronchiectasis patients who were hospitalised in a regional hospital in Hong Kong for exacerbation from 1 January 2019 to 30 June 2022, to assess the association between hyponatraemia during hospitalised exacerbation and the subsequent outcomes.</sec><sec><title>RESULTS</title>169 patients were included in this study, of which 46 (27.2%) had hyponatraemia upon admission. Patients in the hyponatraemia group had shorter overall survival (OS) with a median OS of 31.3 months (95% CI 0.76–717.0) in the hyponatraemia group and 104.4 months (95% CI 0.82–1208.3) in the non-hyponatraemia group, adjusted hazard ratio (aHR) of 1.87 (95% CI 1.09–3.20; P = 0.023). Patients in the hyponatraemia group also had shorter time-to-next hospitalised bronchiectasis exacerbation with a median time-to-next hospitalised bronchiectasis exacerbation of 72.1 months (95% CI 0.25–362.1) in the hyponatraemia group and 144.6 months (95% CI 1.53–1437.8) in the non-hyponatraemia group, aHR of 2.04 (95% CI 1.07–3.88; P = 0.030).</sec><sec><title>CONCLUSIONS</title>This is the first report on the incidence and prognostic value of hyponatraemia in hospitalised bronchiectasis exacerbation, which was observed in 27.2% of patients. It was associated with significantly increased mortality and shorter time-to-next hospitalised bronchiectasis exacerbation when compared with the non-hyponatraemia group.</sec>