Guideline-adherent initial intravenous antibiotic therapy for hospital-acquired/ventilator-associated pneumonia is clinically superior, saves lives and is cheaper than non guideline adherent therapy

Hospital-acquired pneumonia (HAP) often occurring as ventilator-associated pneumonia (VAP) is the most frequent hospital infection in intensive care units (ICU). Early adequate antimicrobial therapy is an essential determinant of clinical outcome. Organisations like the German PEG or ATS/IDSA provide guidelines for the initial calculated treatment in the absence of pathogen identification. We conducted a retrospective chart review for patients with HAP/VAP and assessed whether the initial intravenous antibiotic therapy (IIAT) was adequate according to the PEG guidelines

We collected data from 5 tertiary care hospitals. Electronic data filtering identified 895 patients with potential HAP/VAP. After chart review we finally identified 221 patients meeting the definition of HAP/VAP. Primary study endpoints were clinical improvement, survival and length of stay. Secondary endpoints included duration of mechanical ventilation, total costs, costs incurred on the intensive care unit (ICU), costs incurred on general wards and drug costs.

We found that 107 patients received adequate initial intravenous antibiotic therapy (IIAT) vs. 114 with inadequate IIAT according to the PEG guidelines. Baseline characteristics of both groups revealed no significant differences and good comparability. Clinical improvement was 64% over all patients and 82% (85/104) in the subpopulation with adequate IIAT while only 47% (48/103) inadequately treated patients improved (p < 0.001). The odds ratio of therapeutic success with GA versus NGA treatment was 5.821 (p < 0.001, [95% CI: 2.712-12.497]). Survival was 80% for the total population (n = 221), 86% in the adequately treated (92/107) and 74% in the inadequately treated 'subpopulation (84/114) (p = 0.021). The odds ratio of mortality for GA vs. NGA treatment was 0.565 (p = 0.117, [95% CI: 0.276-1.155]). Adequately treated patients had a significantly shorter length of stay (LOS) (23.9 vs. 28.3 days; p = 0.022), require significantly less hours of mechanical ventilation (175 vs. 274; p = 0.001), incurred lower total costs (EUR 28,033 vs. EUR 36,139, p = 0.006) and lower ICU-related costs (EUR 13,308 vs. EUR 18,666, p = 0.003).

Drug costs for the hospital stay were also lower (EUR 4,069 vs. EUR 4,833) yet not significant. The most frequent types of inadequate therapy were monotherapy instead of combination therapy, wrong type of penicillin and wrong type of cephalosporin.

These findings are consistent with those from other studies analyzing the impact of guideline adherence on survival rates, clinical success, LOS and costs. However, inadequately treated patients had a higher complicated pathogen risk score (CPRS) compared to those who received adequate therapy. This shows that therapy based on local experiences may be sufficient for patients with low CPRS but inadequate for those with high CPRS. Linear regression models showed that single items of the CPRS like extrapulmonary organ failure or late onset had no significant influence on the results.

Guideline-adherent initial intravenous antibiotic therapy is clinically superior, saves lives and is less expensive than non guideline adherent therapy. Using a CPRS score can be a useful tool to determine the right choice of initial intravenous antibiotic therapy. the net effect on the German healthcare system per year is estimated at up to 2,042 lives and EUR 125,819,000 saved if guideline-adherent initial therapy for HAP/VAP were established in all German ICUs.