title: Predictors of mortality in patients with infections due to multi-drug resistant Gram negative bacteria: the study, the patient, the bug or the drug?
abstract: OBJECTIVE
  To study the predictors of mortality among patients with multi-drug resistant Gram negative (MDRGN) infections and the role of MDRGN bacteria in the outcome of such patients.
  
  
  METHODS
  PubMed and Scopus databases were searched (until June 30, 2012). Data were extracted and analyzed using the technique of meta-analysis.
  
  
  RESULTS
  30 studies (25 retrospective) were included in the analysis; 9 provided data on predictors of mortality for MDRGN infections only, while 21 provided data for MDRGN vs non-MDRGN infections. Acinetobacter spp were the most commonly studied bacteria followed by Pseudomonas aeruginosa and Enterobacteriaceae. Significant diversity was observed among studies regarding the evaluated predictors of mortality. Infection severity and underlying diseases were the most commonly reported independent predictors of mortality followed by multidrug resistance, inappropriate treatment and increasing age. In studies that included only patients with MDRGN infections, cancer (RR 1.65, 95% CI 1.13-2.39) and prior or current ICU stay (1.27, 1.02-1.56) were associated with mortality. In studies that included patients with MDRGN and non-MDRGN infections, septic shock (3.36, 2.47-4.57), ICU stay (2.15, 1.45-3.20), pneumonia (1.65, 1.09-2.52), isolation of MDRGN bacteria (1.49, 1.21-1.83), inappropriate definitive (2.05, 1.12-3.76) and empirical treatment (1.37, 1.25-1.51), and male gender (1.13, 1.05-1.21) were most commonly observed in patients who died than patients who survived.
  
  
  CONCLUSIONS
  Significant diversity and statistical heterogeneity was observed. Beyond comorbidity and severity scores, MDR and inappropriate treatment were also identified as predictors of mortality.
authors.affiliation: Alfa Institute of Biomedical Sciences, Athens, Greece.
authors.forename: Konstantinos Z
authors.initials: KZ
authors.lastname: Vardakas
authors.forename: Petros I
authors.initials: PI
authors.lastname: Rafailidis
authors.forename: Athanasios A
authors.initials: AA
authors.lastname: Konstantelias
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Falagas
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D015331:Cohort Studies; D024881:Drug Resistance, Bacterial; D005260:Female; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000302:isolation & purification* / Q000472:pathogenicity; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy / Q000382:microbiology / Q000401:mortality*; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D012307:Risk Factors
chemical_list: D000900:Anti-Bacterial Agents