A new study published in the British Medical Journal of Quality and Safety estimates that one in every 20 out-patients is misdiagnosed. Focusing mostly on studies involving the delayed diagnosis of lung and colorectal cancer, the authors examined cases where a patient had signs or symptoms suggestive of a disease, but the diagnosis was delayed. By extrapolating their statistics to the entire adult population, the authors calculated a rate of erroneous diagnoses over 5%.
Even more concerning, the study estimated that half of those errors had the potential to cause serious harm or even death related to the delay in diagnosis. That means that two or three of every 100 adults may potentially be harmed by a misdiagnosis in an out-patient setting. The causes of these medical errors was varied–ranging from a doctor overlooking potentially serious symptoms, attributing symptoms to a more common or less dangerous cause, or failing to order appropriate testing or follow up on testing that was ordered.
Much has been written about diagnostic errors among hospitalized patients, which are estimated to kill as many as 400,000 patients each year. But researchers have had much more difficulty studying out-patient errors, due to such factors as lack of uniformity among medical records, difficulty in defining diagnostic errors, and the absence of consistent follow-up information. The new study proves that out-patients are not immune from the dangers that plague in-patients.
There are some differences in the causes of in-patient and out-patient errors. Many in-patient errors are due to poor communication among hospital staff, while a common source of out-patient errors is a lack of follow-up for abnormal test results. But both in-patients and out-patients are subject to errors in physician thinking–doctors who ignore symptoms or guess at diagnoses without proper testing.
Many of these diagnostic errors could be reduced if hospitals, medical offices, and professional organizations were to create checklists or algorithms for working up certain groups of symptoms. Yet the medical profession has almost uniformly resisted these kinds of guidelines–not because they are bad for patients, but because they fear that doctors who ignore the guidelines will be held liable for malpractice. Well, yeah. But on the other hand, if these types of guidelines were available, there would be less chance that individual physicians would make diagnosis errors–and fewer patients injured or killed. Seems like that would be good for all concerned.
And in an out-patient setting, patients may be better able to advocate for themselves. Generally, patients are less acutely ill, have more time to ask questions, do their own research, and seek second opinions. These proactive steps won’t eliminate the original mistake–but they may help to reduce the consequences.