A new study, published in BMJ Open, investigates varying approaches to understanding the phenomenon of overdiagnosis across different medical fields. Jenniskens and colleagues from the University Medical Center Utrecht in the Netherlands found that, although consequences of overdiagnosis can be detrimental to patient health, there is no universal definition. The lack of consensus on the issues hinders communication between healthcare workers, patients, and policy-makers.
“Overdiagnosis is discussed across virtually all clinical fields and in different contexts. The variability in characteristics between studies and lack of consensus on overdiagnosis definition indicate the need for a uniform typology to improve coherence and comparability of studies on overdiagnosis,” write the researchers.
The authors categorize overdiagnosis as a subcategory of “over-medicalization,” meaning “too much medicine.” It can be understood as diagnosing an individual with a condition for which they will never experience symptoms or as diagnosing in a way that would not yield a net benefit. For instance, large-scale screening for depression in adults and an ADHD-focused school culture have been linked to overdiagnosis of mental health disorders.
Jenniskens’ team aggregated the list of drivers of overdiagnosis identified across medical disciplines. They found that screening, technological developments that detect smaller abnormalities, inappropriate application of diagnostic criteria, legal incentives, cultural beliefs, and commercial or professional interests are all contributors to the issue.
They also review potential adverse consequences. The effects identified across the different specialties include:
- “negative effects on patient health and additional costs within the healthcare system,”
- “impaired quality of life and early loss of life due to side effects or complications of unnecessary subsequent testing or treatment,”
- psychological repercussions of “incorrectly labeling” a patient,
- indirect “social effects through eligibility for health benefits,” and
- the monetary impact resulting from “unwarranted usage of (follow-up) tests, treatment and healthcare facilities, and services.”
While the harmful impact of overdiagnosis is evident and there are increasing numbers of publications on the subject, Jenniskens and colleagues are the first to perform an analysis distinguishing between “studies focusing on how overdiagnosis should be studied” versus those reviewing the “impact of overdiagnosis in a certain field.” They searched PubMed in August 2017 and then assessed articles based on predetermined criteria, yielding 1,851 studies. Clinical fields were categorized using the ICD-10 classification.
The researchers found papers in all clinical fields, with most published on oncology (50%, mainly breast, prostate, and lung cancer), then mental health disorders (9%, mainly bipolar disorder), infectious diseases (8%, mainly malaria), and cardiovascular disease (6%, mainly pulmonary embolism).
The types of diagnostic tests used in the studies were mostly comprised of imaging, biomarkers, histology, and medical examination. While imaging, i.e., cancer screening, was predominant in oncology, medical examination characterized as an application tool of the DSM was most prevalent within the field of mental health. Notably, only the field of mental health discussed “disease definition” more than “overdiagnosis estimation,” indicating a potential lag in conceptualizing overdiagnosis.
In this study, significant differences lie in different definitions of overdiagnosis based on diverse methodologies and dissimilar typologies. The researchers call for a systematic method, such as comprehensive typology, to improve communication and provide clarity across disciplines. They conclude:
“Future methodological studies should focus on establishing a framework to aid clinicians and researchers in understanding the different subtypes of overdiagnosis, their consequences, and provide guidance for selecting appropriate study designs and methods that match the research question on interest.”
Jenniskens, K, de Groot, J. A. H., Reitsma, J. B., Moons, K. G. M., Hooft, L., & Naaktgeboren, C. A. (2017). Overdiagnosis across medical disciplines: a scoping review. BMJ Open. doi: 10.1136/bmjopen-2017-018448 (Link)