Hospitals Improve Survival Rates While Treating Sicker Patients
Survival rates for U.S. hospital inpatients have improved since 1998, despite predictions that rates would worsen due to the increased severity of the illnesses being treated.
According to "Improvements in Hospital Inpatient Survival Rates, 1998-2006," advances in care realized by U.S. hospitals since 1998 translated into the survival of 350,000 more patients than expected in 2006.
The study also showed that hospitals are treating sicker patients. To analyze this, discharge data and diagnoses codes were used to model expected survival rates which were compared to actual survival rates. Several earlier studies suggested that severity of illness, also called acuity, was rising among select patient groups; the Center for Healthcare Improvement (CHI) study confirmed this trend for all inpatients.
"The good news is that more patients are surviving; the better news is that even more patients than expected are surviving," said Kaveh Safavi, M.D., J.D., chief medical officer, Center for Healthcare Improvement and one of the study's co-authors. "The findings indicate significant progress in improving patient safety, as measured by survival rates, even though the nation's hospitals are facing the challenge of serving a higher percentage of inpatients with illnesses of increased severity."
Improving hospital patient safety has been the focus of a number of initiatives since 1998. For example, the goal of the 100,000 Lives Campaign, conducted by the Institute of Healthcare Improvement (IHI) from January 2005 through June 2006, was to prevent 100,000 deaths in hospital care through specific targeted activities to improve patient safety. (CHI contributed data to IHI's campaign on the estimated change in unnecessary patient mortality risk over time.)
"The objective of quality initiatives like the 100,000 Lives Campaign is to convince U.S. hospitals to uniformly adopt beneficial practices that were previously used inconsistently," noted Safavi. "The fact that the inpatient survival rate has been continuously rising -- despite increasing severity of illness -- indicates that this goal is being achieved."
"We are encouraged by the results of this study, which echo the IHI's own findings that significant numbers of unnecessary hospital deaths were avoided over the last two years," said Donald Berwick, M.D., president and CEO of IHI. "We applaud the hospital staff whose hard work across many quality initiatives including -- but not limited to the 100,000 Lives Campaign -- is responsible for these important improvements."
According to CHI's analysis, in 1998, the estimated actual in-hospital survival rate was 97.8 percent, compared to an expected survival rate of 97.6 percent, based on increasing acuity of hospital patients during that period. By 2003, the variance had grown, as the actual survival rate remained at 97.8 percent while the predicted rate had decreased to 97.3 percent.
Between 2003 and mid-2006, the study showed, the gap continued to widen, as estimated actual in-hospital death rates dropped 13 percent while predicted death rates increased nearly 30 percent. By June 2006, the actual survival rate was at 98.1 percent, while the predicted survival rate had dropped to 96.9 percent.
CHI used two proprietary Thomson Healthcare inpatient databases for its study of mortality and inpatient acuity: the Projected Inpatient Database (PIDB), the primary data source for trends between 1998 and June 2005; and ACTracker(R), the source for trends from July 2005 through June 2006.
The PIDB is a collection of all-payer state and proprietary inpatient data collected from short-term, general, non-federal (STGNF) hospitals. The PIDB aggregates information on more than 18 million patients discharged annually from more than 2,000 hospitals. The PIDB has been used extensively in epidemiological, pharmacological and health services research studies.
The ACTracker(R) database contains approximately 4 million discharges from 400 hospitals annually, but is much more current, with data typically available 45 to 60 days after the date of patient discharge. Both the PIDB and ACTracker databases are projected to be representative of the universe of STGNF hospitals.