Complication rates may not reflect hospital quality of care
for cardiac bypass surgery patients
Patient complication rates should not be used to judge how well
hospitals care for patients undergoing coronary artery bypass
graft (CABG) surgery until more is known about how CABG
complication rates reflect care quality, according to a study
supported by the Agency for Health Care Policy and Research
(HS06560). The study found that many hospital characteristics
that are sometimes thought to be associated with higher quality
of care were associated with expected or lower-than-expected
death rates but also with higher complication rates.
This is surprising, notes Jeffrey H. Silber, M.D., Ph.D., of the
University of Pennsylvania. Logically, there should be more
complications in hospitals with worse outcomes, and those
hospitals generally should provide worse quality of care. Dr.
Silber explains that this apparent paradox may be due to the fact
that hospital deaths are clear-cut events and are reported
consistently, whereas complications are not so easy to identify,
agree upon, or consistently report.
Dr. Silber and coinvestigators obtained data on 16,673 patients
undergoing CABG procedures at 57 hospitals across the Nation and
data from the 1991 American Hospital Association Annual Survey.
They compared the expected number of deaths, complications, and
deaths following complications (failure to rescue) based on
patients' clinical conditions with actual complication rates of
CABG patients at participating hospitals. They also studied
hospital characteristics often used as indicators of quality of
care that were associated with each outcome.
Results showed that of all the patients studied, 43 percent had
complications, 4 percent died, and 10 percent died as a result of
complications. The three hospital characteristics associated with
the highest complication rates were the presence of a magnetic
resonance imaging facility, an approved residency training
program, and a bone marrow transplant (BMT) unit, characteristics
usually associated with high quality of care. These findings
raise serious questions about the usefulness of complication
rates as an indicator of hospital quality of care for patients
undergoing CABG surgery, conclude the researchers.
Details are in "Evaluation of the complication rate as a measure
of quality of care in coronary artery bypass graft surgery," by
Dr. Silber, Paul R. Rosenbaum, Ph.D., J. Sanford Schwartz, M.D.,
and others, in the Journal of the American Medical
Association 274(4), pp. 317-323, 1995.
Greater ICU use does not necessarily translate into fewer
hospital deaths
The more technology-intensive nature of American versus Canadian
medical care is evident in a recent study which shows that the
number of intensive care unit (ICU) days per million people in
western Massachusetts is two to three times that of patients in
Alberta, Canada. The main reason for the difference is the
greater proportion of U.S. hospitalized patients treated in the
ICU rather than a difference in hospital admission rates or
length of ICU stay. Surprisingly, this greater use of ICUs does
not appear to lead to a lower hospital death rate, according to a
study supported in part by the Agency for Health Care Policy and
Research (HS06026).
Led by Stanley Lemeshow, Ph.D., of the University of
Massachusetts, the researchers used hospital discharge data to
compare differences in ICU use and hospital death rates among
50,030 patients admitted to hospitals in Alberta and western
Massachusetts during 1990 and 1991. ICU use in Massachusetts was
significantly higher for all patient groups, except those
undergoing coronary artery bypass surgery, where ICU use was
similar for Alberta and Massachusetts patients. The hospital
death rate in western Massachusetts was similar to, or higher
than, that of Alberta.
Evidence indicates that Alberta, which has fewer ICU beds per
hospital bed and per capita than western Massachusetts, reserves
the ICU for sicker patients. For instance, a much higher
proportion of Alberta ICU patients received mechanical
ventilation; conversely, a greater proportion of Massachusetts
ICU patients undergoing elective surgery were less severely ill
than similar Alberta ICU patients. Compared with patients in
western Massachusetts, patients in Alberta tended to receive
surgery earlier in the day and, if necessary, were kept longer in
the recovery room until their condition stabilized and they could
be transferred to regular beds on a surgical floor. These same
patients in Massachusetts would be more likely to be transferred
to the ICU after surgery until their condition stabilized. Also,
some categories of patients in Alberta were likely to be treated
for extended periods in the emergency department, in contrast to
similar Massachusetts patients, who were rapidly transferred from
the emergency department to the ICU.
For more information, see " A comparison of intensive care unit
utilization in Alberta and western Massachusetts," by John
Rapoport, Ph.D., Daniel Teres, M.D., F.C.C.M., Robert Barnett,
M.B.B.S., and others, in Critical Care Medicine 23(8), pp.
1336-1346, 1995.
Nearly three-quarters of ICU patients in acute renal failure
requiring dialysis die in the hospital
About 70 percent of critically ill patients with acute renal
failure (ARF) requiring dialysis die in the hospital. Although
dialysis can be lifesaving in some circumstances, it may be
unhelpful in others, such as this subgroup of ARF patients,
explains Glenn M. Chertow, M.D., of Brigham and Women's Hospital,
in this report of a study supported by the Agency for Health Care
Policy and Research (HS07118).
He and other researchers developed a model to predict in-hospital
death among these critically ill ARF patients, which they derived
from evaluating the medical records of 132 ICU patients with ARF
who required dialysis. Using patient medical history, clinical
condition, and laboratory results, the model identified 24
percent of high-risk patients who died, without misclassifying
any survivors. Overall, 70 percent of the patients died during
hospitalization, 63 percent of them within 30 days of beginning
dialysis.
According to the model, the need for mechanical ventilation,
malignancy, and nonrespiratory organ system failure were
independently associated with in-hospital death. According to the
researchers, this model may be useful for identifying a fraction
of those patients who will die regardless of dialysis and for
whom a less invasive approach might be appropriate, without
denying renal dialysis to patients who might benefit.
Details are in "Prognostic stratification in critically ill
patients with acute renal failure requiring dialysis," by Dr.
Chertow, Cindy L. Christiansen, Ph.D., Paul D. Cleary, Ph.D., and
others, in the Archives of Internal Medicine 155, pp.
1505-1511, 1995.
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