Evaluation of Optimal Cefazolin Regimen in Hemodialysis Patients
Bibliographic record
Abstract
Background: Cefazolin is commonly used among patients on hemodialysis (HD) to treat gram-positive infections although equipoise persists on the optimal regimen in this specific population. Methods: The primary aim of this observational prospective study was to compare free cefazolin plasmatic concentrations between 3 regimens (2-2-3g post-HD / 1g daily / 2g daily) in adult patients from a single center receiving cefazolin between Sept 2020 and Jan 2022. Our secondary aim was to determine if cefazolin levels were above the local minimum inhibitory concentration (MIC) with each regimen. The antibiotic regimen was determined by the patient's treating team (nephrologists and/or microbiologists) independent from the study. Local MIC's for methicillin-sensitive staphylococcus aureus (MSSA) were measured for patients in whom it was available, with 4 times the MIC considered as a therapeutic target according to the literature. Results: 72 cefazolin dosages were obtained from 25 patients, with 15 patients receiving 2-2-3g post-HD, 6 patients treated with 1g daily and 4 patients with 2g daily. The most frequent indications for cefazolin were catheter infections (n=6), cutaneous infections (n=6) and osteitis (n=5). Of note, two patients had endocarditis and 10 patients (40%) had a MSSA bacteremia. Among patients with bacteremia, two patients were treated with 2-2-3g post-HD regimen, 4 received 1g daily and 4 patients had 2g daily. The mean free plasma concentrations of cefazolin were 23.3±13.6 mg/L, 33.2±12.7 mg/L and 67.5±21.6 mg/L for the 2-2-3g post-HD / 1g daily / 2g daily respectively. The local MICs ranged from 0.25 to 1 mg/L. Conclusions: In all the three regimens, the free plasmatic levels of cefazolin were above the local MIC's. Our data show that a thrice-weekly post-HD regimen should be prioritized in MSSA infection in hemodialysis, especially in outpatient settings, to avoid the need of peripheral access and reduce the time and human resources associated to daily antibiotics. - Regimen Thrice-weekly (n=15) 1g daily (n=6) 2g daily (n=4) p-value Baseline characteristics Age (years) 61.5±16.6 61.8±17.0 45.3±5.9 0.14 Male sex, n (%) 5 (33) 6 (100) 4 (100) 0.004 BMI (kg/m2) 29.3±8.1 28.8±4.2 23.8±3.5 0.57 Diabetes, n (%) 11 (73) 2 (33) 2 (50) 0.24 CAD, n (%) 9 (60) 4 (67) 0 (0) 0.53 Cefazolin indication Endocarditis, n (%) 0 (0) 0 (0) 4 (50) MSSA bacteremia, n (%) 2 (13) 4 (67) 4 (100) 0.002 Daily dose (mg/Kg) 14.0±4.0 11.7±1.8 30.1±10.2 0.01 Dosage Total number of dosages 32 25 15 Free cefazolin dosages (mg) 23.3±13.6 33.2±12.7 67.5±21.6 <0.001
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".