Enterobacterales and Prognostic Nutritional Index in Hospitalised Bronchiectasis: Associations With Mechanical...

To assess associations of Enterobacterales isolation and prognostic nutritional index (PNI) with mechanical ventilation and long-term mortality in bronchiectasis exacerbations.

We conducted a retrospective cohort study of bronchiectasis exacerbations at a university-affiliated tertiary hospital in China between January 2009 and July 2024. Patients were classified into Enterobacterales and non-Enterobacterales groups. The primary outcomes were long-term all-cause and cause-specific mortality; secondary outcomes were invasive mechanical ventilation (IMV) and non-invasive mechanical ventilation (NIMV). Propensity scores for Enterobacterales isolation were estimated using logistic regression for 1:1 nearest-neighbour matching in mortality analyses. Associations with IMV and NIMV were evaluated in multivariable logistic regression models, and mortality in Cox proportional hazards models. Model adequacy was assessed by examining multicollinearity, calibration, discrimination, and proportional hazards, and E-values were calculated to assess robustness to unmeasured confounding.

Among 4634 patients, Enterobacterales were isolated in 228 (4.9%). Enterobacterales isolation was independently associated with IMV (aOR, 2.39; 95%CI, 1.21-6.87; P=.022) and cause-specific mortality over a median follow-up of 72 months (aHR, 1.49; 95%CI, 1.13-2.30; P=.035). In species-level models, Escherichia coli was associated with increased risks of all-cause (aHR, 1.84; 95%CI, 1.18-2.87; P=.007) and cause-specific mortality (aHR, 1.99; 95%CI, 1.13-3.50; P=.017). PNI was inversely associated with risks of IMV, NIMV, and mortality (all P<.001).

Enterobacterales isolation is associated with an increased risk of IMV and cause-specific mortality. In species-level analyses, E. coli was associated with increased risks of all-cause and cause-specific mortality, while elevated PNI was associated with lower mortality.