12 Million Misdiagnoses a Year Due to Gaps in Outpatient Care

Nearly 12 million patients a year are misdiagnosed, and half of those cases could lead to serious health problems, according to a meta-analysis in the journal BMJ Quality & Safety.

Researchers looked at three studies: one of misdiagnosis in primary care settings, and one each for colorectal cancer and for lung cancer that examine screenings and subsequent diagnosis.

The meta-analysis estimates “the frequency of diagnostic error to be at least 5% in U.S. outpatient adults, a number that entails a substantial patient safety risk. This population-based estimate should provide a foundation for policymakers, health care organizations, and researchers to strengthen efforts to measure and reduce diagnostic errors.”

The triggers in the primary care study were unplanned hospitalizations or unscheduled return visits within 14 days of the original visit.

“Although we presumed that the types of errors detected in the primary care study were likely to account for the majority of outpatient diagnostic errors, we also aimed to estimate the rate of errors related to initial diagnosis of less common but serious chronic conditions,” the study states.

Hence, the review of colorectal and lung cancer misdiagnosis. “Unlike misdiagnosis of acute conditions, these errors may not become apparent for weeks or months.”

Red flags were missed. For colorectal cancer this meant a “lack of follow-up 60 days after documentation of hematochezia (bright red blood per rectum), positive fecal occult blood test, and iron deficiency anemia.

“For lung cancer, we defined lack of follow-up as failure to initiate further investigation or an appropriate action within seven days of a documented red flag, such as an abnormal chest X-ray.”

The contribution of the two cancers to the overall estimation of missed diagnoses was small, “but we believe it was important to include them to show their relative contribution. This is because delayed cancer diagnosis is believed to be one of the most harmful and costly types of diagnostic error in the outpatient setting and its significance had become apparent not only in malpractice claims but also in retrospective studies of consecutive cancer cases, surveys, and studies of failures to follow-up abnormal test results.”

What can insurers do? Hardeep Singh, MD, MPH, the study’s corresponding author, says health plans “could work with researchers to identify care patterns in electronic data that suggest … diagnostic errors.”

Singh, a researcher at the Michael E. DeBakey VA Medical Center and Baylor College of Medicine in Hous–ton, says that more evaluation must be done to “bring these triggers to real-world practice, but this is a start. In the future, such measurement techniques could help identify outliers in diagnostic performance.”