NEW YORK, Jun 09 (Reuters Health) - Errors in medical diagnoses fell by half
from the 1970s to 1990s in one Swiss hospital, due mainly to more accurate tests
for cardiovascular diseases, researchers suggest.
In the June 10th issue of The Lancet, investigators report that in 1972,
major errors were made in 30% of diagnoses in patients who died at Zurich's
University Hospital. By 1992, the major error rate had fallen to 14%.
In an interview with Reuters Health, study author Dr. Franco Salomon of the
hospital's department of internal medicine, said that technological
advances--mainly non-invasive procedures that allow doctors to study the heart
and arteries in detail--significantly cut cardiovascular misdiagnoses in the
1980s. In the 1970s, he noted, a growing awareness of the risks for heart
disease brought more people in for tests.
In the study, Salomon's team compared diagnoses with autopsy findings for
300 deaths at the hospital, 100 each in 1972, 1982 and 1992. They looked for
major and minor discrepancies, with major errors including information that
would have changed patients' treatment had it been caught.
The researchers report that while major errors were cut in half, the rate of
minor errors jumped from 23% to 46% over the 20-year period. One explanation for
this, according to Salomon, is that in 1992, patients were living longer with
more complex diseases and undergoing more tests.
The Swiss researchers also note that tests for infectious diseases improved
during the study period, leading to far fewer false-negative results in 1992.
Still, advances in cardiovascular medicine were the most important factor,
Salomon said. For example, pulmonary embolisms--a life-threatening condition in
which a clot blocks lung arteries--were missed far more often in 1972. Heart
attacks were also frequently missed at the time, he explained.
Cancer diagnoses, the investigators found, were highly accurate in 1972 and
remained so in 1992. This was expected, Salomon said, mainly because doctors
have more time in assessing cancer patients.
"With cardiovascular disease," he said, "it can be a question of hours or
minutes."
