Outcomes of octogenarians and nonagenarians with Pseudomonas aeruginosa bacteremia: a multicenter retrospective study

Background P. aeruginosa bacteremia is a common and severe infection carrying high mortality in older adults. We aimed to evaluate outcomes of P. aeruginosa bacteremia among old adults (≥ 80 years). Methods We included the 464/2394 (19%) older adults from a retrospective multinational (9 countries, 25 centers) cohort study of individuals hospitalized with P. aeruginosa bacteremia. Bivariate and multivariable logistic regression models were used to evaluate risk factors for 30-day mortality among older adults. Results Among 464 adults aged ≥ 80 years, the mean age was 84.61 (SD 3.98) years, and 274 (59%) were men. Compared to younger patients, ≥ 80 years adults had lower Charlson score; were less likely to have nosocomial acquisition; and more likely to have urinary source. Thirty-day mortality was 30%, versus 27% among patients 65–79 years ( n = 894) and 25% among patients < 65 years ( n = 1036). Multivariate analysis for predictors of mortality among patients ≥ 80 years, demonstrated higher SOFA score (odds ratio [OR] 1.36, 95% confidence interval [CI] 1.23–1.51, p < 0.001), corticosteroid therapy (OR 3.15, 95% CI: 1.24–8.01, p = 0.016) and hospital acquired P. aeruginosa bacteremia (OR 2.30, 95% CI: 1.33–3.98, p = 0.003) as predictors. Appropriate empirical therapy within 24 h, type of definitive anti-pseudomonal drug, and type of regimen (monotherapy or combination) were not associated with 30-day mortality. Conclusions In older adults with P. aeruginosa bacteremia, background conditions, place of acquisition, and disease severity are associated with mortality, rather than the antimicrobial regimen. In this regard, preventive efforts and early diagnosis before organ failure develops might be beneficial for improving outcomes.