The Pitt bacteremia score, or PBS, reliably predicts 14-day mortality in patients with nonbacteremia carbapenem-resistant Enterobacteriaceae, or CRE, according to study results published in Clinical Infectious Diseases.
“Similar to patients with bloodstream infections, patients without bloodstream infections who had a Pitt bacteremia score of less than 4 experienced a low risk of 14-day mortality, whereas patients with a PBS of 4 or greater had a significantly higher risk,” Heather Henderson, DVM, MPH, a graduate research assistant in the division of infectious diseases at the University of North Carolina, explained to Infectious Disease News.
According to Henderson and colleagues, there are many scoring systems to grade severity of illness, but the PBS has the fewest parameters and is the simplest to calculate.
For their study, Henderson and colleagues included 475 patients from the Consortium on Resistance Against Carbapenems in Klebsiella and Other Enterobacteriaceae, or CRACKLE-1, a prospective, multicenter, observational study of hospitalized patients with CRE. Patients had a CRE cultured from any specimen from December 2011 through June 2016.
According to the study, Henderson and colleagues estimated risk ratios (RRs) to determine the PBS’s predictive ability overall and for each of its individual components — hypotension, mechanical ventilation, mental status, maximum temperature and cardiac arrest. They analyzed each component to predict mortality, assessed the appropriate cutoff value for the dichotomized score and compared the results with the predictive ability of a quick Pitt (qPitt) score, an abbreviated version of the PBS that incorporates all five of its components as binary variables.
A PBS of 4 or greater was associated with mortality in patients with nonbacteremia infection (RR = 21.9; 95% CI, 7-68.8) and with bloodstream infection (RR = 6; 95% CI, 2.5-14.4), Henderson and colleagues reported.
They found that four PBS parameters — hypotension, mechanical ventilation, mental status and cardiac arrest — were independent risk factors for 14-day all-cause inpatient mortality. Although the temperature parameter as originally calculated for the PBS was not independently associated with mortality, a temperature of 36°C or less was independently associated with mortality compared with a temperature of 36°C or greater, according to the study.
The researchers also reported that qPitt scores of 2 or greater was strongly associated with 14-day mortality and concluded that both scores can be used as reliable predictors of mortality in nonbacteremia CRE infections.
“The PBS can be used in future observational studies or clinical trials involving [non-bloodstream] infections, such as pneumonia or complicated urinary tract infections, to stratify patients according to their baseline risk of mortality,” Henderson said. – by Joe Gramigna
Disclosures: Henderson reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.