Review Examines Causes and Consequences of Overdiagnosis in Primary Care

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A review in BMJ probes the sources, costs and possible solutions for overdiagnosis in primary care. Although the full extent of overdiagnosis in primary care is unknown, the phenomenon has been acknowledged for a number of conditions, including indolent breast and lung cancer, depression, and attention-deficit/hyperactivity disorder (ADHD).

Contributors to overdiagnosis include widened diagnostic boundaries, national screening practices, and systemic issues such as misaligned financial incentives. The researchers, Dr. Minal S. Kale of the Icahn School of Medicine at Mount Sinai and Dr. Deborah Korenstein of Memorial Sloan Kettering Cancer Center, identify overtreatment, diagnosis-related distress, labeling, and financial hardship as the potential harms of overdiagnosis in primary care.

“Overdiagnosis is inherent to the modern practice of healthcare, which seeks to diagnose and mitigate disease before it is clinically relevant,” they write. Yet, it “remains the ‘elephant in the examination room’ for a variety of…reasons, including confusion surrounding the meaning of the term, lack of awareness outside the realm of cancer screening, and expectations about healthcare.”

Kale and Korenstein define overdiagnosis as “the diagnosis of a condition (often subsequently treated), that would otherwise not cause symptoms or harm to a patient during his or her lifetime.” They focus on overdiagnosis in primary care due to the field’s population-wide reach.

Much of mental health evaluation and treatment in the U.S. occurs in primary care settings. Primary care physicians (PCPs) now provide the majority of care to those with mental health diagnoses, and they prescribe 79% of antidepressant medications in the U.S. And yet studies have found many PCPs feel inadequately equipped to assess mental health concerns and provide related recommendations and care.

Kale and Korenstein’s paper is based on a systemic literature review of overdiagnosis-related research. Their review was two-pronged: it included a search of studies on overdiagnosis in primary care (n = 71) and a second search of research quantifying overdiagnosis in medicine more broadly (n = 54).

The authors identify several causes of overdiagnosis based on their review. These include the expansion of “disease definitions,” public health screening efforts, and other systemic factors. The widening of disease definitions encompasses both the “lowering of diagnostic thresholds” and the creation of pre-diseases based on risk factors (e.g., pre-diabetes). Screening programs can contribute to overdiagnosis by indiscriminately detecting “all disease along the spectrum of clinical severity” and thus screening in those who may be only mildly affected. The U.S. Preventative Services Task Force’s 2016 recommendation that all individuals age 12 and older be screened for depression is a contemporary example of a screening guideline that has been met with concerns about overdiagnosis.

“When determining the effectiveness of screening, we evaluate the balance between clinical benefit (such as improved mortality) and clinical harm (such as complications from diagnostic tests and treatment) in a screened population,” Kale and Korenstein write.

Systemic conditions, such as financial structures and incentives, encourage overdiagnosis as well. For example, in “fee for service healthcare systems,” practitioners may be incentivized to promote testing even when it is not clinically advisable. The pharmaceutical industry is motivated to develop new drug markets, which it accomplishes through the expansion of disease definitions (e.g., by influencing “diagnostic criteria,” as in the case of the DSM-5). These practices promote overdiagnosis.

Costs of overdiagnosis, which include overtreatment, psychological injury, labeling, and financial loss, reverberate on multiple levels: for individual patients, within the healthcare system, and society-wide. Overtreatment, which is the “unnecessary treatment of a condition,” can harm individual patients through a treatment’s direct negative repercussions, indirect effects of “down-stream services,” and “opportunity costs.” In a system with finite resources, overtreatment is also felt within the healthcare system and society at large through a resulting reduction of access to care for others in need.

Overdiagnosis’s psychological effects can include isolation, despair, and anxiety. The labeling that occurs when a diagnosis is given can also affect one’s self-view and treatment by others. One study cited by Kale and Korenstein illustrates the influence of overdiagnosis on self-concept and behavior: researchers found that patients who received early imaging for “mild acute low back pain,” which frequently identifies “insignificant anatomic abnormalities,” were more often “out of work with a disability” than non-imaged patients one year afterwards.

“This [finding] suggests that the knowledge of an identifiable abnormality may affect people’s perceptions about their own health and engagement in society,” they add.

Lastly, overdiagnosis has significant financial costs – for example, breast cancer overdiagnosis amongst 40-59-year-old women in the U.S. has been calculated to cost $1.2 billion.

“Because overdiagnosis is an expected consequence of screening in asymptomatic people, some degree of overdiagnosis will persist,” the researchers write. “However, the ethical obligation to avoid patient harm compels physicians to minimize the prevalence of overdiagnosis…”

Kale and Korenstein offer several proposals regarding how the field of primary care can begin to address the issue of overdiagnosis. In their paper, they establish clear definitions of overdiagnosis and related, often confused terms (e.g.  overuse, overtreatment, overmedicalization, misdiagnosis), and advocate for these definitions to be adopted more widely, to the benefit of future research and clinical practice. They push for an improved “evidence base,” including calculations of overdiagnosis rates and harm/benefit analyses for screenings; the streamlining of “disease definitions”; and improved oversight via recognition of overdiagnosis in guideline development standards. They also suggest that primary care doctors can help mitigate overdiagnosis by discussing it with patients and engaging in “conservative management” of early stage/mild conditions.

“Better understanding of overdiagnosis by physicians and how best to manage it, along with an appreciation of the phenomenon by patients, will be important as we try to minimize both its prevalence and its harms in primary care,” they conclude.

 

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Kale, M. S., & Korenstein, D. (2018). Overdiagnosis in primary care: framing the problem and finding solutions. BMJ, 362, k2820. (Link)