Table 2

Quality assessment of included studies (RCTs)

Cochrane risk of bias tool (for RCTs)
Type of biasSelectionPerformanceDetectionAttritionReporting
Author, yearRandom sequence generationAllocation concealmentBlinding of participants and personnel*Blinding of outcome assessment*Incomplete outcome dataSelective reporting
Arrossi et al, 201521Medium†LowLowLowLowLow
Bais et al, 200722LowMedium‡LowLowLowLow
Broberg et al, 201423Medium‡Medium‡LowLowLowLow
Cadman et al, 201524LowLowLowLowLowLow
Carrasquillo et al, 201825LowLowLowLowLowLow
Darlin et al, 201327Medium‡Medium‡LowLowLowMedium††
Giorgi Rossi et al, 201130LowLowLowLowLowLow
Giorgi Rossi et al, 201529LowLowLowLowLowLow
Gok et al, 201031LowMediumLowLowLowLow
Gök et al, 201232LowMedium‡LowLowLowMedium††
Gustavsson et al, 201833LowLowLowLowLowLow
Haguenoer et al, 201434LowLowLowLowLowLow
Ivanus et al, 201835LowLowLowLowLowLow
Kellen et al, 201836LowHigh§LowLowLowLow
Lazcano-Ponce et al, 201138Medium¶LowLowLowLowMedium††
Modibbo et al, 201739High**MediumLowLowLowMedium††
Moses et al, 201540LowLowLowLowMediumLow
Murphy et al, 201641LowLowLowLowLowLow
Piana et al, 201142LowMedium‡LowLowMediumHigh††‡‡
Racey et al, 201654LowLowLowLowMediumLow
Sancho-Garnier et al, 201343Medium‡Medium‡LowLowLowMedium††
Sewali et al, 201544LowLowLowLowLowLow
Sultana et al, 201645LowLowLowLowLowMedium
Szarewski et al, 201146Medium3Medium3LowLowLowLow
Tranberg et al, 201847LowLowLowLowLowLow
Tranberg et al, 2018 (subanalysis)48LowLowLowLowLowLow
Virtanen et al, 201150LowMedium‡LowLowLowLow
Viviano et al, 201751LowLowLowLowLowLow
Wikström et al, 201152Medium‡Medium‡LowLowLowLow
Zehbe et al, 201653Medium†MediumLowLowMediumMedium
  • Green: low risk of bias; yellow: medium risk of bias; red: high risk of bias.

  • *Given the intervention of interest (self-sampling for HPV testing), blinding was not possible for participants and personnel, nor was it possible to blind for outcome assessment. However, the measured outcomes (uptake of cervical cancer screening, frequency of HPV testing, social harms/adverse events and linkage to care) are unlikely to be influenced by lack of blinding. For uptake, the outcome was measured by lab/medical records (number of kits sent in for testing and number of patients who got the Pap smear or VIA), not by self-report. For linkage to care, the outcome was measured through medical records, not by self-report.

  • †Cluster-randomised community health workers or communities to self-sampling and control arms.

  • ‡Details of the randomisation and/or allocation process are not documented.

  • §Timing of screening invitation was different for the intervention group compared with the control group.

  • ¶Non-random factor is included in design (eg, women randomised to the self-sampling arm who were not at home when visited by researcher were reassigned to control/conventional cytology).

  • **Randomisation occurred after enrolment.

  • ††Intention to treat was not reported.

  • ‡‡Women in the self-sampling arm could opt out; those who did were excluded from the analysis (possibly leading to an artificially high participation rate in the self-sampling arm).

  • HPV, human papillomavirus; RCT, randomised controlled trial; VIA, visual inspection with acetic acid.