Hospital Volume and Sepsis Mortality

By Andy Skean
Senior Editor

Multiple studies have reported that septic patients have better outcomes if they are treated at centers with high yearly case volumes of sepsis, according to Jared A. Greenberg, MD, MSc, from Rush University Medical Center. “This association is believed to be related to greater clinician expertise with managing sepsis at these high-volume hospitals and other organizational factors,” he says. “Much of the focus on improving sepsis outcomes has been on early interventions, but some patients have poor outcomes because their chronic medical conditions may worsen in the days or weeks after an initial infectious insult.”

For a study published in Annals of the American Thoracic Society, Dr. Greenberg and colleagues sought to determine whether the odds of death for immunosuppressed patients with sepsis varied according to the hospital’s yearly case volume of these individuals. They looked at more than 350,000 patients with sepsis from 60 different hospitals in a 2010-2012 database who were characterized as immunosuppressed or not immunosuppressed based on certain medical conditions and medication use. “Our focus was on immunosuppressed patients because these individuals are at greater risk for developing sepsis and dying from it,” adds Dr. Greenberg. “We hypothesized that greater clinician expertise at managing chronic conditions may improve outcomes from sepsis as well.”

Key Findings

Overall, 1 out of every 5 patients with sepsis was categorized as immunosuppressed. “We found that 15% of immunosuppressed septic patients died during their hospitalization, compared with 12% of non-immunosuppressed septic patients,” Dr. Greenberg says (Table). Septic patients who were immunosuppressed were 23% more likely to die during the hospitalization than septic patients without immunosuppressive conditions, after adjusting for multiple patient- and hospital-level variables.

The number of cases of immunosuppressed septic patients per hospital per year was also associated with in-hospital mortality. “At hospitals seeing fewer than 225 immunosuppressed patients with sepsis per year, immunosuppressed patients with sepsis were 38% more likely to die while hospitalized than non-immunosuppressed individuals,” says Dr. Greenberg. “At hospitals seeing more than 225 immunosuppressed sepsis patients each year, immunosuppressed patients with sepsis were only 21% more likely to die than non-immunosuppressed patients with sepsis.”

Interestingly, immunosuppressed patients with sepsis were more likely than non-immunosuppressed patients to return to home after discharge rather than another health facility (60% vs 50%, respectively). This finding may be the result of several factors, such as non-immunosuppressed patients being older than immunosuppressed patients and being more likely to have been admitted directly from other healthcare facilities than home.

Assessing Implications

The research team quantified the degree to which immunosuppressive conditions were associated with the risk of death from sepsis. “Our study is important for administrators and clinicians who focus on the quality of sepsis care at their hospital,” Dr. Greenberg says. “Patients with relatively uncommon medical conditions may have worse outcomes from sepsis in the hospital than those with the same conditions who are managed at hospitals where the condition is more common.”

There are many potential reasons for immunosuppressed patients having the highest mortality risk from sepsis at hospitals managing the fewest number of immunosuppressed patients with sepsis, and more research is necessary. “A prospective multi-center study of septic patients would be helpful to determine if our main finding is due to differences in patient characteristics or care delivery at hospitals with varying exposure to immunosuppressed patients,” says Dr. Greenberg. “Additional studies are also needed to investigate differences in long-term outcomes from sepsis according to patients’ immune states.”

Dr. Greenberg says the study results suggest that septic patients may benefit from being treated at hospitals that manage the most sepsis. “Patients may also benefit from being treated at hospitals with a certain level of familiarity managing comorbid conditions that have been identified as risk factors for developing sepsis,” he says.