Impact of Superinfection on Hospital Length of Stay and Costs in Patients with Ventilator-Associated Pneumonia

ABSTRACT

Ventilator-associated pneumonia (VAP) increases length of stay (LOS) in VAP versus non-VAP patients, but LOS differences among VAP patients remain unexplained. We explored the economic impact of developing a respiratory superinfection while being treated for VAP.

This was a retrospective, observational cohort study conducted in 74 patients discharged between January 2004 and July 2005 identified as having VAP. Using detailed, chart-abstracted demographic and hospital-course data—including antibiotic therapy, APACHE II scores, and superinfection development—multivariable analysis determined variables independently associated with LOS and total accounting costs from the date of VAP identification (VAP ID) to discharge or death.

Overall mortality and mean ± SD APACHE II were 35% and 19.4 ± 8.9 for 74 cases; 35% of the cohort developed a superinfection. Pseudomonas aeruginosa, Staphylococcus aureus, and Klebsiella spp. were most frequently responsible. Mortality was unaffected by superinfection. Younger age (p = 0.003), superinfection (p = 0.006), and admission to the surgical intensive care unit (ICU) (p = 0.014) independently predicted LOS (adjusted R ² = 0.296). Younger age (p < 0.001), admission to the surgical ICU (p = 0.004), superinfection (p = 0.002), and previous antibiotic exposure (p = 0.009) predicted increased costs (adjusted R ² = 0.394). Mean (95% CI) LOS and total costs after contracting VAP were greater for superinfection patients [47.8 days (39.0 to 56.5) versus 27.9 (22.4 to 33.1), p < 0.001; $140,850 ($98,426 to $183,275) versus $73,801 ($58,946–$88,656), p < 0.001], with 15.6 days and $48,527 attributable to superinfection.

While not affecting mortality in those patients with VAP, superinfections independently predict increased LOS after VAP ID, contributing to substantial additional cost.

KEYWORDS

Ventilator-associated pneumonia - superinfection - length of stay - hospital costs - bacteria resistance

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