ZDoggMD on Overdiagnosis: When More Medicine Makes Patients Worse

This article discusses ideas from ZDoggMD — Dr. Zubin Damania, MD , Stanford/UCSF-trained internist, founder of the Health 3.0 movement. Full archive: zdoggmd.com | YouTube @zdoggmd

American medicine has a cultural assumption so deeply embedded it's rarely examined: more testing, more diagnosis, and more treatment means better care. ZDoggMD has pushed back on this assumption with evidence. Overdiagnosis — finding and treating conditions that would never have caused harm — is a real, measurable, and significant source of patient harm.

What Overdiagnosis Actually Is

Overdiagnosis occurs when a true abnormality is detected — the test result or pathology finding is real — but the condition would never have progressed to cause symptoms or death. The patient ends up diagnosed with and treated for a condition that would have been irrelevant to their health if it had gone undetected.

The most studied examples: thyroid cancer (a dramatic increase in diagnosed cases has not produced a corresponding reduction in thyroid cancer deaths — we're diagnosing cancers that weren't killing anyone), ductal carcinoma in situ (DCIS) in breast cancer screening (many DCIS lesions would never progress to invasive cancer), and PSA-based prostate cancer screening (many screen-detected cancers are treated aggressively despite evidence they would have remained indolent).

Why the System Pushes Toward More

ZDoggMD identifies three drivers of overdiagnosis in the current system: fee-for-service reimbursement (more procedures, more revenue), defensive medicine (ordering tests to document thoroughness rather than because they'll change management), and the cultural equation of testing with caring that both physicians and patients have internalized.

There is also a real asymmetry in how errors are perceived: a missed diagnosis generates visible, documented harm — a malpractice claim, a complaint, a sentinel event review. An overdiagnosis generates invisible harm — the patient with an indolent thyroid cancer who received unnecessary surgery and lifelong thyroid replacement doesn't know what happened to them without it. The visible risk pushes toward more testing; the invisible risk gets no countervailing pressure.

What ZDoggMD Recommends

Shared decision making that presents screening and testing in terms of absolute benefits and harms, not relative risk reduction. Choosing Wisely guidelines that identify tests and treatments with unfavorable benefit-harm ratios. A cultural shift away from the assumption that more is better — and toward asking, for each intervention: will this actually help this specific patient?

ZDoggMD on evidence-based medicine and overdiagnosis:

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