Overdiagnosis – the growing threat to health

April 20, 2015


Jack O’Sullivan

On September 15-17th 2014, academics, doctors, patients and policy makers gathered at the University of Oxford to discuss an ever-growing threat to health: overdiagnosis. The 2014 Preventing Overdiagnosis conference, the second of its kind from The Dartmouth Institute, Bond University’s Centre for Research in Evidence Based Practice, Oxford University’s Centre for Evidence Based Medicine and The British Medical Journal was a landmark occasion. A variety of topics were covered, from the harms of screening programs to dangerous, unnecessary use of invasive interventions.

Significantly, defining Overdiagnosis was debated ardently. Although discussion is on going, simplicity, Overdiagnosis is a diagnosis of a benign, asymptomatic ‘disease’: that is, a ‘disease’ that will not progress to cause harm. These diseases are recognised formally, in screening programs,1 or incidentally,2 during investigation for a different reason. They are also captured by widening disease definitions (e.g. pre-diabetes)3 and labeling of non-specific or psychosomatic symptomatology (e.g. motivational deficiency disorder).4

This innovative meeting also examined the dangers of overdiagnosis. Broadly, harms are to patients (psychological and physical) and to health care systems. On reflection, it seems obvious that labeling a patient as ‘diseased’ can induce anxiety5. Despite this, screening programs are performed often without adequate explanations of the chance of misdiagnosis or the possibility of adverse outcomes post intervention.6 This is particularly worrying given screening can be erroneous and induce harm.1,5

Physical harms of overdiagnosis include the side effects of medications and unnecessary interventions. Rustam Al-Shahi’s presentation on the treatment of incidental brain findings was a good example of harmful, unnecessary intervention. Al-Shahi reported that cerebral haemorrhage is more likely using invasive cerebral angiography to ‘cure’ atriovenous malformations and other incidental cerebrovascular abnormalities than leaving these lesions alone.

Further, overdiagnosis harms our vulnerable health care system. It’s not good medicine and wastes health care resources. Investing in diagnostics and treatments that cause no benefit is costly6 and diverts funds from areas that desperately need it.

Perhaps most significantly, the conference addressed the challenges we face mitigating overdiagnosis. Unfortunately, it seems that there’s no single culprit. Overdiagnosis is the result of systemic vulnerabilities within medicine. Doctor’s ever-increasing medicolegal fear is one lingering driver, however medicine’s intuitive ‘more is better’ culture was a more prominent theme at this meeting. As a practising doctor, I can attest to the strong pressures of ‘not wanting to miss anything’. Although this meticulous desire reflects the benevolence that characterises medicine, I fear our best intentions are misplaced. As Iona Heath surmises, ‘patients need clinicians courageous enough to reassert the border between the well and the sick’.

Patient expectation, contentious evidence, issues measuring prevention and financial incentives to test and treat are additional factors fueling overdiagnosis. It seems patients may be accustomed to receiving something from doctors8. A 60-year old man not having Prostate specific antigen (PSA) test, for example, may be a hard concept for clinicians to explain and for patients to accept. Worryingly, often patients are not told of the potential adverse consequences from a PSA test7. These problems of communication are reflective of highly contentious evidence.8,9,10 The conflicting evidence leaves clinicians feeling lost. Fundamentally, as David Haslam, chair of NICE argued, it is very difficult to measure and communicate prevention: ‘no one knows if they have avoided a heart attack’. Hence when a patient doesn’t receive a diagnosis, treatment or a PSA test, it is hard for all parties to comprehend the avoided consequences.

The wonderful array of evidence presented at Preventing Overdiagnosis 2014 was an alarming insight into the harms of too much medicine. We do lots of good as doctors, however this conference highlighted medicine’s neglect of its defining and fundamental principle: Primum non nocere – first do no harm.

  1. Jorgensen KJ, Gotzsche PC. Overdiagnosis in publicly organised mammography screening programmes: systematic review of incidence trends. BMJ 2009; 339: b2587.
  2. Orme NM, Fletcher JG, Siddiki HA, et al. Incidental findings in imaging research: evaluating incidence, benefit, and burden. Arch Intern Med 2010 Sep 27; 170(17): 1525-32.
  3. Moynihan R, Heath I, Henry D. Selling sickness: the pharmaceutical industry and disease mongering. BMJ 2002 Apr 13; 324(7342): 886-91.
  4. Moynihan R. Scientists find new disease: motivational deficiency disorder. BMJ 2006 Apr 1; 332:745
  5. Woolf SH, Harris R. The harms of screening: new attention to an old concern. JAMA 2012 Feb 8; 307(6): 565-6.
  6. O’Dowd A. Patients are deceived over benefits and risks of screening, MPs hear. BMJ 2014; 348: g3960.
  7. Berwick DM, Hackbarth AD. Eliminating waste in US health care. JAMA 2012 Apr 11; 307(14): 1513-6.
  8. Schroder FH, Hugosson J, Roobol MJ, et al. Screening and prostate cancer mortality: results of the European Randomised Study of Screening for Prostate Cancer (ERSPC) at 13 years of follow-up. Lancet 2014 Aug 6.
  9. Andriole GL, Crawford ED, Grubb RL, et al. Prostate cancer screening in the randomized Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial: mortality results after 13 years of follow-up. J Natl Cancer Inst 2012 Jan 18; 104(2): 125-32.
  10. Ilic D, Neuberger MM, Djulbegovic M, et al. Screening for prostate cancer. Cochrane Database Syst Rev. 2013; 1: CD004720.

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