Infected patients do worse than even sickest controls
Severity of illness less a factor in poor outcomes
It may seem intuitive, even obvious to experienced ICPs, but acquiring an infection during hospitalization is about as bad as it gets for a patient. Even patients with a host of maladies that compromise their recovery fared significantly better in outcomes than patients who acquired infections.
The finding comes in a recently published cohort study involving thousands of patients that concluded that "observed differences in mortality, length of stay and charges between patients with HAIs and those infection free could not be explained on the basis of increased disease-specific severity at the time of admission."1 In the study, nine cohorts (i.e., heart failure, chronic obstructive pulmonary disease, respiratory failure, pneumonia, hip fracture, major surgical complications, colonic resection, diabetes, and gastrointestinal bleeding) were examined for differences in mortality, length of stay, and hospital charges.
"We found people who were the sickest amongst the sick as controls," explains principal investigator Richard Johannes, MS, MD, vice president for clinical research at Cardinal Health, MediQual in Marlborough, MA. "One of the things that would have been easy to do — and that we didn't do — was simply compare the people with hospital-acquired infection with congestive heart failure against people with congestive heart failure that didn't acquire an HAI. But we found [controls] that were every bit as sick based on clinical parameters such as white cell count, blood pressure, degree of renal failure and the like — all measured with clinical parameters, not ICD 9 codes. These people were equally sick — and there were five controls compared to every case — so they had every opportunity to have an equally adverse outcome, but they didn't."
In particular, mortality rates remained significantly higher in the HAI cases as compared to matched non-HAI controls across the same disease groups. "If you get an HAI your mortality rates increase by a factor of between 1.5 to 5 times for the nine diseases that we looked at," he says. "Charges increased up to 10 times and length of stay increased by an excess of three weeks. What I am trying to say is that severity [of illness] certainly is a factor, but it does not account for the adverse outcomes, which are coming from the HAIs."
The study in conjunction with two others published simultaneously in the same journal raise doubt about the prevailing dogma that many infections are the inevitable price of providing care to severely ill patients.
"It suggests, as the other studies do as well, that these things aren't cast in stone," Johannes says. They are not inevitable. I think all three of these articles tend to reinforce one another even though they were done independent of one another. None of us had read the others articles until they actually had been accepted."
The study used data previously collected under Pennsylvania's infection rate disclosure law. The validity of the data have been questioned, but Johannes emphasized he thoroughly validated all cases and controls in the cohort study.
"In addition to the claims data, I also have laboratory values, vital signs and about 40 chart abstracted elements on each of these discharges," he says. "So I had very solid clinical data to base this on."
Reference
- Peng MM, Kurtz S, Johannes RS. Adverse outcomes from hospital-acquired infection in Pennsylvania cannot be attributed to increased risk on admission. Am J Med Qual 2006; 21(suppl):17S-28S.
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