DENVER – In obese patients with vancomycin-resistant enterococcal bacteremia, using a dose of daptomycin based on adjusted body weight rather than actual body weight resulted in similar efficacy and outcomes. It also resulted in more than $1,800 in medication cost savings per patient, judging from findings of a small pilot study.
"I feel very comfortable using adjusted-dose daptomycin for patients with VRE bacteremia, especially in those with uncomplicated bacteremia," lead investigator Jerod Nagel, Pharm.D., said in an interview at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
Jerod Nagel, Pharm.D.
"I think we need some more data evaluating the right dose for complex patients regardless if they’re obese or not – whether it’s 6, 8, 10 or 12 g/kg."
He and his associates retrospectively evaluated the outcomes of 47 obese adult inpatients with VRE bacteremia being treated with daptomycin at the University of Michigan Hospitals and Health System. Of the 47 patients, 31 received 6 mg/kg daptomycin based on actual body weight (actual body weight group) and 16 received 6 mg/kg daptomycin based on adjusted body weight (defined as 0.35-0.5 [actual body weight minus ideal body weight] plus ideal body weight) from September 2010 to May 2012.
Outcomes of interest included 30-day all-cause mortality, length of stay, microbiologic clearance, recurrent bacteremia, and antibiotic cost based on an average wholesale price of $382.44 per 500 mg. Toxicity also was evaluated.
The rate of clinical cure was similar between the two groups (37.5% in the adjusted body weight group vs. 38.7% in the actual body weight group), as was the rate of recurrent bacteria (13% vs. 3%, respectively), mortality (19% vs. 25%), length of hospitalization (a mean of 26.6 days vs. 41.8 days), time to microbiologic cure (a mean of 2.6 days vs. 2.24 days), and increase in creatine kinase (38% vs. 45%), reported Dr. Nagel of the health system’s department of pharmacy, Ann Arbor.
The researchers also found that, in the adjusted weight group, daptomycin resulted in $1,822 in costs savings per patient, or approximately $44,000 in annual savings.
"I think this study is a good starting point, but more studies are needed for these complex patients and obese patients," Dr. Nagel said. "We have a small sample size, but we showed similar outcomes and a pretty good cost savings. We need a lot more data on how to dose drugs in obese patients, especially in mg/kg, because obese patients will require higher levels and be at risk of toxicity."
Dr. Nagel said that he had no relevant financial conflicts to disclose.