Loading dose plus continuous/extended infusion versus intermittent bolus of β-lactams for the treatment of Gram-negative bacteria bloodstream infections: a propensity score-adjusted retrospective cohort study

• Published in: Journal of antimicrobial chemotherapy 2023-09, Vol.78 (9), p.2175-2184
• Main Authors: Bavaro, Davide Fiore, Belati, Alessandra, Diella, Lucia, Frallonardo, Luisa, Guido, Giacomo, Papagni, Roberta, Pellegrino, Carmen, Brindicci, Gaetano, De Gennaro, Nicolò, Di Gennaro, Francesco, Denicolò, Sofia, Ronga, Luigi, Mosca, Adriana, Pomarico, Francesco, Dell’Aera, Maria, Stufano, Monica, Dalfino, Lidia, Grasso, Salvatore, Saracino, Annalisa
• Format: Article
• Language: English
• ISSN: 0305-7453; 1460-2091
• DOI: 10.1093/jac/dkad215

Abstract Background Optimal β-lactam dosing for the treatment of Gram-negative bacteria bloodstream infections (GNB-BSIs) remains a debated issue. Herein, the efficacy and safety of a loading dose (LD) followed by extended/continuous infusion (EI/CI) versus intermittent bolus (IB) of these drugs for the treatment of GNB-BSIs was evaluated. Methods This is a retrospective observational study enrolling patients with GNB-BSIs treated with β-lactams from 1 October 2020 to 31 March 2022. The 30 day infection-related mortality rate was assessed with Cox regression, while mortality risk reduction was evaluated by an inverse probability of treatment weighting regression adjustment (IPTW-RA) model. Results Overall, 224 patients were enrolled: 140 and 84 in the IB and EI/CI groups, respectively. β-Lactam regimens were chosen according to pathogen antibiogram, clinical judgement and current guidelines. Interestingly, the LD + EI/CI regimen was associated with a significant lower mortality rate (17% versus 32%, P = 0.011). Similarly, β-lactam LD + EI/CI was significantly associated with a reduced risk of mortality at multivariable Cox regression [adjusted HR (aHR) = 0.46; 95%CI = 0.22–0.98; P = 0.046]. Finally, the IPTW-RA (adjusted for multiple covariates) was performed, showing a significant risk reduction in the overall population [−14% (95% CI = −23% to −5%)]; at the subgroup restricted analysis, a significant risk reduction (>15%) was observed in the case of GNB-BSI in severely immunocompromised patients (P = 0.003), for SOFA score > 6 (P = 0.014) and in septic shock (P = 0.011). Conclusions The use of LD + EI/CI of β-lactams in patients with a GNB-BSI may be associated with reduced mortality; also in patients with severe presentation of infection or with additional risk factors, such as immunodepression.