DIAGNOSTIC errors are becoming more prominent in medical indemnity claims in Australia but accurate measurement remains a problem, say leading experts.
The problem of diagnostic errors has been raised in a US study showing diagnostic errors have become the “most common, most costly and most dangerous of medical mistakes”.
The study, published in BMJ Quality and Safety, found equal numbers of lethal and non-lethal diagnostic errors among malpractice claims, with the authors suggesting the public health impact of diagnostic errors could be substantially greater than previous estimates based on autopsy data, which consider only lethal errors. (1)
After analysing 350 706 paid claims from the National Practitioner Data Bank (1986–2010) the authors found that “diagnostic errors were the leading type (28.6%) and accounted for the highest proportion of total payments (35.2%)”.
“Diagnostic errors more often resulted in death than other allegation groups (40.9% vs 23.9%) and were the leading cause of claims-associated death and disability”, they wrote.
The most frequent types of diagnostic error were failure to diagnose (54.2%), delay in diagnosis (19.9%) and wrong diagnosis (9.9%).
Professor David Studdert, from the University of Melbourne’s School of Population and Global Health, told MJA InSight that he was a little surprised that diagnostic errors had eclipsed surgical claims in the US study.
“The numbers probably translate quite well to the Australian situation”, he said. “It’s been true for a long time that diagnostic errors and surgical errors have been the top reasons for claims, but in the last 10 years diagnostic errors seem to have become more prominent.”
However, he urged caution in interpreting the US data, saying much depended on the way errors were categorised.
A diagnostic error, as defined by the US study, is a diagnosis that is “missed, wrong, or delayed, as detected by some subsequent definitive test or finding”.
“The predominant diagnostic error in Australia is the missed cancer diagnosis, particularly breast and colon cancers”, Professor Studdert said.
“There’s been very little research done about diagnostic errors … because they are very hard to measure. We’re talking about omissions rather than commissions. A lot of the time with a diagnostic error, nothing happens as a result and so there is no harm.”
The most recent Australian data were from 2010–11 which showed procedural errors made up 33.7% of new public sector claims, while diagnostic errors made up 26.5% (data exclude WA). (2)
Dr Michael Smith, clinical director of the Australian Commission on Safety and Quality in Health Care, told MJA InSight the major difference between the US and Australia in regard to diagnostic errors was the “ethos of malpractice” in the US.
“Our legal system is perhaps not quite so focused on malpractice as they are over there, but proportionately the numbers are probably quite similar”, he said.
“You have to remember that we have 8.5 million hospital admissions a year, 12 million clinic attendances, 125 million general practice services being offered. And from those, there’s maybe one claim per half-million contacts.”
However, the low claim rate did not mean efforts should not be made to reduce diagnostic errors, Dr Smith said.
“In the past few years there has been more focus on trying to reduce diagnostic errors”, he said.
“About half of all diagnostic errors are cognitive — the doctor sees the symptoms but just can’t put it all together into a diagnosis.
“The other half is system errors — the lab result that goes missing, for example. A classic is the abnormal result that gets put into a patient’s file, but the GP isn’t informed, and if the patient doesn’t come back, the diagnosis is missed or delayed.
“There are systems that can be put in place by medical practices to reduce those errors”, Dr Smith said. “That’s the sort of work that’s starting to happen nationally.”