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

Background: The impact of total body weight (TBW) on 30-day mortality 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 30-day mortality of TBW <70 kg vs. >/ = 70 kg with a multivariable stepwise logistic regression adjusting for age >/ = 70 years, cancer diagnosis, and Pitt bacteremia score of >/ = 4. Results: The cohort was 57% TBW >/ = 70 kg and 43% TBW <70 kg. TBW >/ = 70 kg patients had lower 30-day mortality (11.0% vs. 16.3%), which was significant in the multivariable analysis (OR 0.45, 95% CI 0.21–0.97). Cancer and Pitt bacteremia score >/ = 4 were also independently associated with 30-day mortality. TBW was no longer significant when TBW <50 kg patients were excluded. Conclusion: TBW >/ = 70 kg was associated with an improved 30-day mortality; however, the high mortality rates for patients with a TBW < 50 kg is responsible for this association.