Admission to a hospital when most of the beds are already full can be deadly for patients, according to a new University of Michigan Health System study showing high occupancy increases the risk of dying in the hospital by 5.6%.
For the study, published in the March issue of Medical Care, researchers evaluated a set of critical factors that can affect hospital deaths: hospital occupancy, nurse staffing levels, weekend admission and seasonal influenza.
Having more nurses made patients safer, decreasing risk by 6%. But weekend admission raised the risk by 7.5% and admission during widespread seasonal flu had the greatest impact by increasing the risk of death by 11.7%, according to the study.
Because of the size of the study which included 166,920 adult patients admitted to 39 Michigan hospitals through a 3-year period, the findings can be generalized to hospitals nationwide, authors said in a news release.
“The study establishes that there is indeed a connection between hospital occupancy and death rates in U.S. hospitals,” lead author Peter L. Schilling, MD, MSc, a resident in orthopedic surgery at U-M Health System, said. “It’s important to emphasize though that this study does not identify a specific occupancy level above which patient care suffers and deaths abruptly become more common. The key occupancy level may differ for each hospital.
Researchers calculated the occupancy of the hospitals every day for the years 2003-2006. On average, patients in the study were admitted while hospital occupancy was 73% of full capacity. One-third of patients were admitted on high occupancy days, at average levels of 80% or more.
Study patients were admitted after being seen in the emergency department for a heart attack, congestive heart failure, stroke, pneumonia, hip fracture or gastrointestinal bleeding.
“Hospital occupancy changes from day to day, so patients shouldn’t try to choose a hospital based on its occupancy level,” co-author Matthew M. Davis, MD, MAPP, co-director of the Robert Wood Johnson Foundation Clinical Scholars Program at the U-M, said. “But these kinds of study findings should prompt hospitals to look at the flow of patients and processes of their care teams during high occupancy times. Those are more challenging moments when more things can go wrong.”