Inappropriate antibiotic therapy (IAT) represents a major determinant of outcomes in pneumonia, bacteremia, and sepsis. In earlier analyses, the rates of IAT were high ( > 30%). Recent data on the prevalence of IAT and its effect on outcomes when the rate of this is lower are lacking.
We reviewed outcomes in patients who, over a 3 yr period, presented to the hospital with severe pneumonia requiring mechanical ventilation. We included patients with both community-acquired (CAP) and healthcare-associated pneumonia (HCAP). We based the diagnosis on signs and symptoms along with chest imaging. We only included persons with evidence of acute bacterial infection (e.g. positive lower respiratory tract cultures, blood cultures, or urinary antigen testing). Mortality represented the primary endpoint. IAT was defined as 1) administration of an anti-infective to which the pathogen was in vitro resistant or 2) > 24 hr delay in appropriate antibiotic treatment (AT). We controlled for confounders (e.g. demographics, severity of illness, co-morbid illnesses, etc.) via logistic regression.
The cohort included 190 subjects (mean age: 60.9 ± 15.9 yrs, 54.2% male) and resistant pathogens (MRSA, P. aeruginosa) were present in a third of patients. The overall hospital mortality was 39.5%. Approximately 20% of subjects were given IAT; half being inappropriate because of delay and half due to resistsance. Patients who died were more severely ill (higher APACHE II scores, more vasopressors use) and were more likely to have underlying malignancies. Mortality rates were lower in the IAT cohort (24.4% vs 43.6%, p = 0.03). Independent predictors of mortality included APACHE II score, age, need for vasopressors, and concomitant bacteremia. IAT was not independently associated with death.
IAT therapy rates may be declining compared to historic reports. When IAT rates are low this does not seem to affect hospital mortality.
The absence of IAT's impact on mortality suggests that if physicians strive to reduce IAT they can focus on other issues in order to improve outcomes.
Matthew Schreiber, Grant monies (from industry related sources) Astellas, GSK, J and J, Pfizer, Sanofi; Consultant fee, speaker bureau, advisory committee, etc. Astellas, BI, GSK, J and J, Medicines Co. Merck, Pfizer, Sanofi, Theravance; No Product/Research Disclosure Information