Intended for healthcare professionals

Analysis Too Much Medicine

Mapping the drivers of overdiagnosis to potential solutions

BMJ 2017; 358 doi: (Published 16 August 2017) Cite this as: BMJ 2017;358:j3879

Re: Mapping the drivers of overdiagnosis to potential solutions

The problem is that EBM as currently promulgated does not include the tools to find the solutions to over-diagnosis. EBM is in reality evidence based screening (supported by sensitivity and specificity) and efficacy (supported by RCTs). There is far more to medicine than screening and efficacy.

RCTs are not used currently to identify who benefits and to what extent. Sensitivity and specificity are used to assess non-numerical screening tests and to place cut-offs for numerical tests. They do not help to assess tests for use in differential diagnosis, diagnostic criteria and or offering treatments to patients to consider, which is why we have over-diagnosis and over-treatment.

One example of how to assess tests in order to avoid over-diagnosis was described in an over-diagnosis conference some years ago by stratifying patients within an RCT [1]. However, there seems to have been little interest in solutions until now. If we wish to apply such solutions, we need doctors and other health professionals who are familiar with the thought processes of day to day patient care who are also mathematicians and statisticians. This approach is now being taught to students [2].

It is not only the public, industry and health professionals who need a change of culture and education. There is a need for those who do research and promulgate EBM to expand their skills and horizons in order that they can help to provide solutions to current problems.

1. Llewelyn H. Reducing over -diagnosis and over-treatment by improving their criteria and stratifying them. Preventing Overdiagnosis Conference, Oxford, 2014, poster 34.

2. Llewelyn H, Ang AH, Lewis K, Abdullah A. The Oxford Handbook of Clinical Diagnosis, 3rd edition. Oxford University Press, Oxford, 2014, pp 615 – 664.

Competing interests: No competing interests

21 August 2017
Huw Llewelyn
Consultant Physician. Hon. Departmental Fellow in Mathematics
Aberystwyth University
Penglais, Aberystwyth, Ceredigion, SY23 3FL