Table 1

Characteristics of included studies (n=154)

N (%)
Publication year
 1999–201046 (29.9)
 2011–2022108 (70.1)
Language of publication
 English136 (88.3)
 Spanish11 (7.1)
 Turkish5 (3.2)
 Mandarin1 (0.7)
 Persian1 (0.7)
Income group
 Single country142 (92.2)
 Low income14 (9.1)
 Lower middle income59 (38.3)
 Upper middle income69 (44.8)
Multiple countries12 (7.8)
Study design
 Interventional (e.g., RCT)17 (11.0)
  Randomised trials (e.g., cluster RCTs)13 (8.4)
 Observational (e.g., cross-sectional)125 (81.2)
  Cross sectional (e.g., survey)78 (50.6)
  Prospective cohort34 (22.1)
 Secondary research (e.g., review)9 (5.8)
Analysis approach
 Quantitative125 (81.2)
 Qualitative23 (14.9)
 Mixed6 (3.9)
Condition
 Malaria and other infectious61 (39.6)
 Thyroid cancer and other cancers25 (16.2)
 Heart and lung diseases15 (9.7)
 Diabetes4 (2.6)
 Mental illnesses2 (1.3)
 Other8 (5.2)
 Not specified39 (25.3)
Diagnostic or screening tests
 Imaging (e.g., CT scan, MRI)25 (16.2)
  CT scan (e.g., multidetector CT)7 (4.5)
  MRI (e.g., multiparametric MRI)8 (5.2)
  X-ray (e.g., mammography, DXA) & US6 (3.9)
  Multiple imaging types4 (2.6)
 Lab investigations (e.g., blood tests)18 (11.7)
  Blood tests (e.g., full blood count, lipid)9 (5.8)
  Serological tests (e.g., hepatitis, HIV tests)5 (3.2)
  Others (e.g., tumour markers, d-dimer)4 (2.6)
 Procedures (e.g., colonoscopy)14 (10.1)
  Endoscopies (e.g., colonoscopies)9 (6.2)
  Urogenital (e.g., prostate biopsies and pap smears)3 (1.9)
  Others (e.g., coronary angiographies)2 (1.3)
 Not specified97 (62.2)
Financial implications mentioned
 Considered29 (18.8)
 Not considered125 (81.2)
Main contexts
 Overdiagnosis70 (45.5)
 Overuse of tests61 (39.6)
 Both23 (14.9)
  • DXA, dual-energy X-ray absorptiometry; RCT, randomised controlled trials; US, ultrasound scan.