What is overdiagnosis?
Overdiagnosis occurs when individuals are diagnosed with conditions that will never cause symptoms or death. It converts ordinary people to be patients by identifying conditions that cause no harm and/or ‘medicalising’ ordinary life experiences through extended definitions of disease.
Overdiagnosis is the precursor of over-medicalisation and overtreatment, diagnosis creep, shifting thresholds, and disease-mongering. All such processes help to reclassify healthy people with mild problems or at low-risk, as sick.
Overdiagnosis is not:-
- a false-positive diagnostic test
- the same as overtreatment whether unnecessary, or over-aggressive treatment
- synonymous with over-testing
Too much medicine emanates from combined overdiagnosis and overtreatment.
Why is Overdiagnosis important?
USA expenditure on healthcare is the highest, approaching 18% of the GDP. Estimated cost of healthcare waste, identified in six domains, ranges from $760 billion to $935 billion, about 25% of the total healthcare spending. Overtreatment or low-value care is one of the six domains which account for $12.8 billion to $28 billion. In the USA, the average expenditure for each false-positive mammogram, invasive breast cancer, and ductal carcinoma in situ, in the year following diagnosis between 2011-2013 were $852, $51,837 and $12,369, respectively. This translates to a national cost of $4 billion each year.
Too much medicine is not just a problem of the rich countries. South Asia needs even better recognition of the manifestations and drivers of overdiagnosis. The latter region may have some unique features because of cultural and contextual differences.
Other than massive expenditure, the psychological trauma and anxiety, imposed sometimes for life, because of overdiagnosis, have not been estimated. Furthermore, “too much testing of healthy people and not enough care provided for the sick, worsens health inequalities and deters professionalism, harming both those who need treatment and those who do not.”
What are the drivers of overdiagnosis?
In a nutshell Iona Heath says that it is because of a “A toxic combination of vested interests and good intentions”
Thanya Pathirana has produced a summary of the drivers and solutions in one inforgraphic.
Fig 1 Overdiagnosis and related overuse. Mapping possible drivers to potential solutions. COI=conflict of interest; OD=overdiagnosis; OU=overuse. Mapping the drivers of overdiagnosis to potential solutions. Thanya Pathirana, Justin Clark Ray Moynihan. Center for Research in Evidence Based Practice, Bond University, Australia.
Examples of Overdiagnosis: Too Much Medicine
The classic but controversial example is mammography breast cancer screening. The aim is to lower the number of women who die of breast cancer. When we explain the findings to patients, we use decision aids that would make it easier to understand the epidemiological facts.
Supplement to: Hersch J, Barratt A, Jansen J, et al. Use of a decision aid including information on overdetection to support informed choice before breast cancer screening: a randomised controlled trial. Lancet 2015; published online Feb 18. http://dx.doi.org/10.1016/S0140-6736(15)60123-4.
Out of 1000 women who had breast screening for 20 years, 4 women avoided dying from breast cancer because of screening and 8 women still die from breast cancer (Fig 1).
Screening leads to finding some breast cancers that are not harmful (over-detection). The cancers found by screening are treated to try and prevent problems later. But some cancers found by screening would not cause problems anyway. Cancers like this may grow very slowly or just stay the same. Without screening, they would never have been noticed or would cause any trouble. Finding these cancers through screening is over-detection (or over-diagnosis).
Over-detection over 20 years of screening in Australia
Out of 1000 women who had breast screening for 20 years, 73 women were diagnosed with breast cancer. Of these, 19 women experienced over- detection; they were treated for a cancer that would not have caused any trouble. (Fig 2). Screening leads to some false positive results and further extra testing. Like many screening tests, a mammogram is not perfect. Sometimes the result looks abnormal and the woman is recalled for extra tests. It may turn out that there is no cancer: a false alarm. These false alarms from screening are called false positive results.
Women often feel anxious while they are having the extra tests and while waiting for their results, and then feel relieved when they are told that there is no cancer. However, some women find that they keep worrying about breast cancer for a while afterwards. Out of 1000 women who had breast screening for 20 years, 412 women experienced a false positive result: they had an abnormal mammogram followed by extra tests, but they did not have cancer. Of these, 67 women had a biopsy and 345 women had other extra tests but no biopsy (Fig 3).
The Ministry of Health guidelines has been updated in 2019 and are available at https://www.nccp.health.gov.lk/pdf/publications/guidelines/GuideLine.pdf. However, if you search the web for ‘breast cancer screening guidelines in Sri Lanka’ you can see for yourself how some private hospitals advertise breast screening which come to the top of the weblinks and the National Cancer Control Programme link down below at eighth or ninth place.
In the 1990s, arthroscopic debridement of the knee for osteoarthritis was performed about 650,000 times per year in the USA, despite the fact that it had not been shown to be beneficial. It is now being advertised in a number of private hospitals in Sri Lanka. In 2019 a Cochrane Review concluded that no placebo or sham-controlled trials were available for the review. The review concluded that ‘there is uncertainty around the current evidence to support or oppose the use of surgery in mild to moderate knee osteoarthritis. As no benefit has been demonstrated from the low-quality trials included in this review, it is possible that future higher quality trials for these surgical interventions may not contradict these results.’
What can be done?
Introducing the topic overdiagnosis to medical students, doctors and public will be a good start for the awareness programme. One of the key concepts, that will be difficult to make people understand, will be that ‘more is not always better’ even in healthcare and ‘less is perhaps more’. Oxygen in acute uncomplicated myocardial infarction is a good example. It was difficult to convince doctors that 100% oxygen saturation might do more harm during an ongoing myocardial infarction. It is now recommended that supplementary oxygen be given only when the saturation is below 90%.
Early detection of everything may not always give the desired effect. Breast cancer screening is the best example.
Health systems problems and solutions
Reforming incentives for professionals and healthcare organisations to reward the quality rather than quantity of care is commonly cited as a key way to tackle the problem of too much medicine.
Everyone is aware of the kickbacks offered by pharmaceutical companies: kickbacks from overdiagnosis at times. In the USA, the Open Payments Programme catalogues payments made to physicians by pharmaceutical and device companies and classifies payments by type. Between 31 August and 31 December 2016 alone, physicians received 4.4 million payments, totalling US$ 2.6 billion. In Sri Lanka there is no such mandatory register of payments made to doctors by pharmaceutical companies.
Industry and technology
More rigorous evaluation of the effects of both new and existing diagnostic testing on health outcomes is needed as a key solution to the emergence of increasingly sensitive tests that detect “abnormalities” of uncertain clinical significance. Detecting otherwise harmless pulmonary emboli in a CT scan done for a different reason is one such example.
Genetic testing is currently undertaken to diagnose diseases or to predict serious diseases with the opportunity to offer a specific intervention. In some diseases genetic tests can help – e.g. BRCA1 and BRCA 2 breast cancer genes. Even these genes predict a risk, not a certainty of developing breast cancer. The penetrance ranges from 30% to 70%. The new wave of genome scanning tests may be a looming disaster of overdiagnosis as they become available freely, even in Sri Lanka. For example, a 25-year old woman receives the first genome scan report: a 4 fold risk of ovarian cancer, decreased risk of lung cancer and a debatable increase in the risk of breast cancer. In addition, there may be an increased risk of heart disease and the presence of genetic variants that both increased and decreased her risk of macular degeneration. What are you going to do about this information? The only thing that almost all doctors would agree is that she doesn’t start smoking. What can be discussed are removing her ovaries because of the 4 fold increase in ovarian cancer but then what about her heart disease because the protective oestrogens will stop? Will this increase her breast cancer risk?
The need to tackle the medico-legal concerns regarding missing or delaying a diagnosis was one of the key solutions discussed in the literature in the US. However as litigation is not that rampant and still the patients trust the doctors to do the best, an open discussion about the tests would solve the problem in most situations.
Patients and public
Widespread awareness campaigns to inform and educate patients and the public on harms as well as benefits of screening and treatment options are commonly cited as essential to tackling overdiagnosis; echoing and overlapping with solutions we have classified in the cultural domain.
Another frequently recommended solution was promoting shared decision- making as a response to several key drivers in this domain. However still the majority of our consultations are doctor-centered because the patients expect the doctors to take the initiative and recommend the test or medicine.