A new study in BMJ Quality and Safety, an international journal of healthcare improvement, estimated that one in 20 adults in the United States could be misdiagnosed in outpatient visits. The study found that approximately half of those mistakes could cause the patient harm.
The researchers set the definition of misdiagnosis as a missed opportunity to make a correct or timely diagnosis based on the evidence available. A misdiagnosis may be an instance of a physician making an incorrect diagnosis, or it may be a case of a delay in diagnosis. The researchers performed an analysis of data from three previous studies of outpatients in the United States, with the goal of estimating the frequency of misdiagnoses.
Researchers examined data on lung cancer misdiagnoses, delays in colon and prostate cancer diagnoses, and diagnostic mistakes in the primary care setting. The authors of the study said that diagnostic errors are often multifaceted, and that factors such as unclear clinical guidelines, cognitive biases and the structure of outpatient systems may play a part in misdiagnoses.
The researchers also said that misdiagnoses are underreported, which is a problem in itself. In the period between 1986 and 2010, payouts for medical malpractice claims due to misdiagnoses amounted to $38.8 billion. Diagnostic mistakes accounted for the largest percentage of malpractice payouts.