TOPLINE:

The laboratory-based Frailty Index showed strong predictive ability for mortality and relapse in patients with carbapenemase-resistant Klebsiella pneumoniae bloodstream infections. 

METHODOLOGY:

• Researchers conducted this retrospective cohort study to validate the Frailty Index-Laboratory as a predictor of treatment response and death in patients with bloodstream infections caused by multidrug-resistant K pneumoniae.
• A total of 182 participants, including survivors (n = 134; mean age, 62.8 years; 65.7% men) and nonsurvivors (n = 48; mean age, 70.3 years; 62.5% men), were assessed.
• The Frailty Index-Laboratory includes parameters such as blood counts; liver, renal, and pancreatic function tests; blood glucose levels; lipid profiles; serum electrolyte levels; coagulation and inflammatory marker levels; and hormonal profiles.
• The primary outcome was overall mortality, and secondary outcomes included 28‑day mortality and relapse, defined as recurrence of the causative organism in blood cultures accompanied by clinical deterioration within 28 days after prior clearance.

TAKEAWAY:

• Nonsurvivors were older, had greater organ dysfunction severity, and demonstrated significantly higher Frailty Index-Laboratory scores than survivors (0.66 vs 0.33; P < .0001).
• The Frailty Index-Laboratory showed excellent predictive accuracy for in-hospital mortality with 100% sensitivity and 76.2% specificity, 28-day mortality with 100% sensitivity and 69.1% specificity, and relapse with 79.2% sensitivity and 77.3% specificity (P < .0001 for all).
• Each 0.10-point increase in the Frailty Index-Laboratory score was associated with an increased likelihood of mortality (adjusted hazard ratio [aHR], 2.07; P < .0001), 28‑day mortality (aHR, 1.86; P < .0001), and infection relapse (aHR, 1.52; P = .03).

IN PRACTICE:

“Unlike traditional comorbidity indices or organ dysfunction scores, FI-Lab [Frailty Index-Laboratory ] offers a snapshot of systemic physiological reserve based solely on routine laboratory values, making it a practical and scalable tool for bedside risk stratification,” the author wrote. 

SOURCE:

This study was led by Carmen Pellegrino, University of Bari Aldo Moro, Bari, Italy. It was published online on October 07, 2025, in the Journal of Antimicrobial Chemotherapy. 

LIMITATIONS:

The absence of stratification between monotherapy and combination therapy limited the granularity of the study findings. In addition, the lack of detailed clinical data on infection episodes, including specific infection sites and wards of acquisition, may have affected the applicability and interpretation of the Frailty Index-Laboratory in this context.

DISCLOSURES:

This study was partially supported by EU funding within the NextGenerationEU-MUR PNRR Extended Partnership initiative on emerging infectious diseases. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.