One in 20 US adults affected by erroneous outpatient diagnoses
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More than 5% of adults in the United States are affected by diagnostic errors during routine outpatient care, according to recent study findings.
Researchers integrated data collected from three prior studies of clinic-based populations addressing the subject of diagnostic error among US patients. Two of the studies used electronic algorithms to identify unusual patterns indicative of inpatient care errors, such as unusual return visits (in a study assessing primary care) or lack of follow-up on abnormal clinical findings for colorectal cancer (in a study assessing colon cancer). In a third study, data was collected from consecutive lung cancer cases at two institutions. Diagnostic errors were confirmed via chart review in all three studies.
The researchers applied the frequency of diagnostic errors observed among these studies to the adult US population. Data from the primary care study was used to approximate error rates for acute conditions, and the two cancer studies were used to make conservative estimates of missed colorectal and lung cancer diagnoses.
The algorithms in the primary care study included an unplanned hospitalization within 14 days of an index visit (n=1,086 total visits), at least one unscheduled visit within 14 days of an index visit (n=14,777 total visits) and control visits that met neither criterion (n=193,810 total visits). All visits across two health systems from Oct. 1, 2006, to Sept. 30, 2007, were included. Within these three groups, researchers estimated 5,126 diagnostic errors, for an estimated error rate of 6.29% among patients. Extrapolation to the US population indicated an estimated error rate of 5.06% for primary outpatient care.
In the colon cancer study, an estimated 26 errors occurred among 291,773 patients (0.009%), which the researchers extrapolated to 0.007% of the adult population experiencing colorectal cancer-related errors per year. The lung cancer study indicated 127 errors across 587 cases, for an error rate of 21.64% for the cohort. Researchers estimated a rate of diagnostic errors related to lung cancer of 0.013% per year for the general population.
After combining estimates from the three studies, researchers established a rate of outpatient diagnostic errors of 5.08%, or roughly 12 million US adults per year, and they estimated that approximately half of these oversights had the potential to result in severe harm to the patient.
“We estimate the frequency of diagnostic error to be at least 5% in US outpatient adults, a number that entails a substantial patient safety risk,” the researchers wrote. “This population-based estimate should provide a foundation for policymakers, health care organizations and researchers to strengthen efforts to measure and reduce diagnostic errors.”
Disclosure: The researchers report no relevant financial disclosures.