Severe sepsis mortality rate lower in hospitals with higher case volumes
Hospitals with higher case volumes of severe sepsis exhibited lower rates of severe sepsis-related hospital mortality without a corresponding increase in costs, researchers have found.
“In the absence of novel therapeutics, processes of care are important determinants of outcomes in patients with severe sepsis,” study researcher Allan J. Walkey, MD, MSc, of the Boston University School of Medicine, told Infectious Disease News. “Whether academic hospitals with more experience caring for severe sepsis patients have better patient outcomes is currently unclear.”
The retrospective cohort study gleaned data related to US-based sepsis hospitalizations in 2011 from the University HealthSystem Consortium clinical database. Researchers accessed information from 124 academic medical centers and utilized the consortium standardized mortality index to quantify severe sepsis mortality.
Hospital features such as the number of acute care beds, ICU structure, long-term acute care hospital referral practices and geographic location were documented. For severe sepsis cases, the researchers also compiled data pertaining to hospital length of stay, direct costs and mortality.
The researchers identified for analysis 56,997 adult patients aged 18 to 95 years. Severe sepsis case volumes were calculated using algorithms from the ICD-9-CM. B-spline regression was used to determine the unadjusted association between severe sepsis case volume and severe sepsis-related mortality, whereas multivariable analysis of covariance models were used to determine the adjusted correlation between quartiles of severe sepsis case volume and severe sepsis death.
Researchers found that during 2011, hospitals admitted 460 ± 216 patients with severe sepsis, with a median length of stay of 12.5 days (interquartile range [IQR], 11.1-14.2]. The median direct cost was $26,304 (IQR, $21,900-$32,090), and the average hospital mortality rate was 25.6 ± 5.3%. An association was seen between higher severe sepsis case volume and lower unadjusted severe sepsis mortality (P=.01), as well as between higher case volume and risk-adjusted severe sepsis mortality (P<.001).
Hospitals in the highest quartile of severe sepsis case volume were found to have an absolute 7% (95% CI, 2.4-11.6) lower hospital mortality than those in the lowest quartile, after adjusting for geographic region, number of beds and long-term acute care referrals.
The researchers theorized that hospitals with more severe sepsis cases — and therefore more experience — may become more skilled in the care of these patients.
“Further studies that seek to determine the specific structures and processes of care associated with improved outcomes at the high volume hospitals are needed to reduce the disparities in severe sepsis outcomes at lower severe sepsis case volume centers,” Walkey and colleagues wrote.
Disclosure: The researchers report no relevant financial disclosures.