Main findings grouped to the main themes addressed in a set of included studies (n=154)
| Study | Key findings |
| Estimation of overdiagnosis and/or overuse of diagnostic and screening tests (n=72) | |
| Vaccarella 2021 (47 countries) A population-based study of 159 registries including 8049 children and adolescents with thyroid cancer.53 | Rapid increase in the incidence rates of thyroid cancer among children and adolescents in almost all countries, although thyroid cancer mortality rates remained low in these countries. This epidemiological pattern mirrored the pattern in adults—suggesting a major role of overdiagnosis, which, in turn, can lead to overtreatment, lifelong medical care and side effects that can negatively affect quality of life. |
| Panato 2020 (India) A population-based study of 14 cancer registries of >5% of Indian population.43 | Thyroid cancer incidence rates increased by 37% and 27% in women and men between 2006–2008 and 2012–2014, respectively. Overdiagnosis accounted for >50% of thyroid cancer in women. Authors concluded that ‘As a society, we must do what it takes to minimise harms to patients and to the already overstretched healthcare systems of these countries’. |
| Ozbek 2010 (Turkey) A retrospective study of 56 349 patients admitted to a university hospital between 2007–2009.54 | More than 1/10 of hepatitis B tests were unnecessary, resulting in an economic loss of approximately US$20 000 over 3 years in a single hospital. |
| Zhang 2018 (China) A retrospective study of 2706 patients in the respiratory, thoracic surgery, and oncology departments of 3 hospitals between 2014 and 2015.45 | The inappropriate use of tumour markers was widespread, ranging between 58% and 79%. This resulted in a financial burden equivalent to 7.69%–12.00% of examination expenses and 1.35%–2.11% of hospitalisation costs. |
| Drivers of overdiagnosis and/or overuse of diagnostic and screening tests (n=27) | |
| Soares 2019 (Brazil) A nationwide population-based survey of 13 625 men older than 40 years.55 | Prostate cancer screening with digital rectal examination is very prevalent in Brazil (63.3%–41.6%) – most frequently carried out within private health insurance, which increase the risk of overdiagnosis and overtreatment. |
| Chandler 2008 (Tanzania) A qualitative ethnographic study of 2082 patient consultations with 34 clinicians over a period of 3 months.30 | Four key drivers of malaria overdiagnosis identified: flawed training, peer pressure and professional norms, perceived patients’ preferences, and limited quality diagnostic resources and support. |
| Consequences of overdiagnosis and/or overuse of diagnostic and screening tests (n=41) | |
| Kavosi 2021 (Iran) A cross-sectional study of 385 participants had undergone brain MRI in three public teaching hospitals.56 | More than one-fifth of brains MRIs were inappropriate—resulting in a financial burden of almost US$100 000 in 1 year in just three hospitals—17 times Iran’s GDP per capita. |
| A-Elgayoum 2009 (Sudan) A retrospective study of 3203 patients from 95 health facilities.57 | Malaria overdiagnosis was widely recognised in Sudan, with massive economic burden—estimated to be US$86 million in 2000. |
| Solutions for the problem of overdiagnosis and/or overuse of diagnostic and screening tests (n=14) | |
| Henao-Villada 2016 (Colombia) A before and after study of 1365 children with bronchiolitis to evaluate the impact of guideline implementation.58 | A marked increase in the proportion of bronchiolitis patients with an appropriate diagnosis and management (36.4% vs 44.5%) and a further decrease in the use of low value care such as unnecessary haemogram (33.2% vs 26.6%). |