Impact of total body weight on 30-day mortality in patients with gram-negative bacteremia

Potential Excess Intravenous Antibiotic Therapy in the Setting of Gram-Negative Bacteremia

(1) Background: Excessive intravenous therapy (EIV) is associated with negative consequences, but guidelines are unclear about when switching to oral therapy is appropriate. (2) Methods: This cohort included patients aged ≥18 years receiving ≥48 h of antimicrobial therapy for bacteremia due to Escherichia coli, Pseudomonas aeruginosa, Enterobacter, Klebsiella, Acinetobacter, or Stenotrophomonas maltophilia from 1/01/2008-8/31/2011. Patients with a polymicrobial infection or recurrent bacteremia were excluded. Potential EIV (PEIV) was defined as days of intravenous antibiotic therapy beyond having a normal WBC count for 24 h and being afebrile for 48 h until discharge or death. (3) Results: Sixty-nine percent of patients had PEIV. Patients who received PEIV were more likely to receive intravenous therapy until discharge (46 vs. 16%, p < 0.001). Receipt of PEIV was associated with a longer mean time to receiving oral antimicrobials (8.7 vs. 3 days, p < 0.001). The only factors that impacted EIV days in the multivariable linear regression model were the source of infection (urinary tract) (coefficient -1.54, 95%CI -2.82 to -0.26) and Pitt bacteremia score (coefficient 0.51, 95%CI 0.10 to 0.92). (4) Conclusions: PEIV is common in inpatients with Gram-negative bacteremia. Clinicians should look to avoid PEIV in the inpatient setting.

Impact of piperacillin/tazobactam on nephrotoxicity in patients with Gram-negative bacteraemia

Piperacillin/tazobactam (TZP) has been associated with nephrotoxicity in patients receiving vancomycin. Its impact on nephrotoxicity in patients with Gram-negative bacteraemia (GNB) is unclear. This study evaluated the impact of TZP on nephrotoxicity in patients with GNB. This retrospective cohort included patients aged ≥18 years receiving ≥48 h of therapy for bacteraemia due to Escherichia coli, Pseudomonas aeruginosa, Enterobacter, Klebsiella, Acinetobacter or Stenotrophomonas maltophilia from 1/01/2008-8/31/2011. Patients with baseline serum creatinine (SCr) ≥3.5 mg/dL, polymicrobial infection or recurrent bacteraemia were excluded. Nephrotoxicity was defined as a ≥0.5 mg/dL increase in SCr or ≥50% increase from baseline for ≥2 consecutive days. Any variable demonstrating a 10% change in exposure effect was retained in the final model. All variables biologically reasonable causes of nephrotoxicity were also considered for inclusion. The median age of the cohort (n = 292) was 76 years; 38.0% had a cancer diagnosis and ICU residence was common (21.9%). There was no difference in nephrotoxicity incidence based on days of TZP received (0 days, 13.6%; 1-2 days, 14.7%; 3-4 days, 6.9%; ≥5 days, 16.7%; P = 0.71). In multivariable analysis, baseline SCr, total body weight and vasopressor use were independently associated with nephrotoxicity. Duration of TZP was not associated with nephrotoxicity in multivariable analysis (1-2 days, OR = 0.91, 95% CI 0.39-2.12; 3-4 days, OR = 0.48, 95% CI 0.10-2.46; ≥5 days, OR = 0.57, 95% CI 0.11-3.02). In this cohort of GNB patients, duration of TZP was not associated with nephrotoxicity.

Impact of total body weight on acute kidney injury in patients with gram-negative bacteremia

BACKGROUND

The impact of total body weight (TBW) on the development of acute kidney injury (AKI) associated with gram-negative bacteremia has not been previously evaluated.

METHODS

The cohort included 323 patients >/ = 18 years old with gram-negative bacteremia (1/1/2008-8/31/2011) who received >/ = 48 hours of antibiotics. We compared the incidence of AKI in patients with a TBW </ = 80kg vs. >80kg with a multivariable stepwise logistic regression adjusting for age >/ = 70 years, baseline serum creatinine of > 2.0 mg/dl, and receipt of a vasopressor. AKI was defined as an increase of 0.5 mg/dL or a > 50% increase from baseline for at least two consecutive days.

RESULTS

The cohort was 62% TBW </ = 80kg and 38% TBW >80kg. TBW >80kg patients had higher risk of AKI (24% vs. 9%, p < 0.001), which was significant in the multivariable analysis (OR 3.41, 95% CI 1.73-6.73). A baseline serum creatinine of > 2.0 mg/dl and vasopressor use were also independently associated with AKI.

CONCLUSIONS

TBW >80kg was associated with the development of AKI. However, the mechanism for this association is not clear.