Medical errors are underestimated and could be the third leading cause of death in the U.S., say doctors calling for more transparency internationally. 

Death certificates in Canada, the U.S. and the U.K. rely on a mortality coding system — the International Classification of Disease code, or ICD — that doesn't capture fatal consequences due to failures in health care. The ICD is used in medical record-keeping in 117 countries, including Canada. 

Estimates of how often people die not from a disease but from the care they received is based on limited and outdated methods, Prof. Martin Makary and research fellow Michael Daniel, of Baltimore-based Johns Hopkins University, say in Wednesday's issue of The BMJ (formerly the British Medical Journal).

"People tend to think about an individual doctor's mistake, but we're really talking much more broadly about system failures, about wrong diagnosis, about medication errors and communication breakdowns," Makary said in an interview.

Makary looked at four U.S. studies from 1999 onwards. He compared the death rates to hospital admissions in 2013 and extrapolated an estimate of how many people died due to medical error that year: 251,454.

If confirmed, and if deaths from medical errors were considered a disease, then medical errors would rank as the third leading cause of death in the U.S. after heart disease and cancer, based on the U.S. Centers for Disease Control and Prevention's list, the researchers say.

Some hospitals in Canada and the U.S. only collect patient safety information on a voluntary basis. This includes diagnostic errors, errors in planning and anything else that affects safety.

He proposes ways to estimate medical errors more accurately, make health-care systems more reliable and share findings in the U.S. and internationally:

  • Make errors more visible when they occur so their effects can be intercepted.
  • Have remedies on hand to rescue patients.
  • Add a field to death certificates to note whether a preventable complication stemming from the patient's medical care contributed to the death.
  • Have hospitals carry out rapid and efficient independent investigation into deaths to see how they  potentially contributed to error.

A landmark Canadian report in 2004 found 7.5 per cent of patients admitted to acute care hospitals in Canada in 2000 experienced one or more adverse events — which refers to things like wrongly administered medications, bed sores, falls, infections and surgical errors. More recent international studies showed rates of adverse events in hospital of between 10 and 14 per cent. 

With files from CBC's Kas Roussy