Table 5, Strengths and Limitations of Clinical Studies using the Downs and Black checklist - HPV Self-Sampling for Primary Cervical Cancer Screening: A Review of Diagnostic Test Accuracy and Clinical Evidence

Table 5Strengths and Limitations of Clinical Studies using the Downs and Black checklist¹¹

Strengths	Limitations
Randomized controlled trials
Polman et al., 2019¹⁵
- Hypothesis described - Outcomes to be measured described - Patient characteristics described - Intervention described - Distributions of principal confounders described - Main findings described - Estimates of random variability provided - Important adverse effects explicitly described - Patients lost to follow-up described - Individuals asked to participate representative of the population from which they were recruited - No significant changes to health care that the participants received, compared to that the majority received - Similar lengths of follow-up for participants in different groups - Appropriate statistical tests to assess the outcomes - Measures of compliance reliable - Accurate outcome measures - Participants recruited from the same period of time - Participants recruited from the same population - Participants randomized to different groups - Confounding adjusted in the analysis	- Participants not blinded - Outcome assessors not blinded - Intervention allocation not concealed - Participants lost to follow-up not taken into account - Power analysis for sample sizes not conducted
Ajenifuja et al., 2018¹⁶
- Hypothesis described - Outcomes to be measured described - Patient characteristics described - Intervention described - Distributions of principal confounders described - Main findings described - Estimates of random variability provided - No patients lost to follow-up reported - No significant changes to health care that the participants received, compared to that the majority received - Similar lengths of follow-up for participants in different groups - Appropriate statistical tests to assess the outcomes - Measures of compliance reliable - Accurate outcome measures - Participants recruited from the same period of time - Participants recruited from the same population - Participants randomized to different groups - Confounding adjusted in the analysis	- Participants not blinded - Outcome assessors not blinded - Intervention allocation not concealed - Power analysis for sample sizes not conducted - Important adverse effects not explicitly described - Actual probability values (P values) not reported
Non-randomized studies
Thay et al., 2019¹⁷
- Hypothesis described - Outcomes to be measured described - Patient characteristics described - Intervention described - Distributions of principal confounders described - Main findings described - No patients lost to follow-up reported - No significant changes to health care that the participants received, compared to that the majority received - Similar lengths of follow-up for participants in different groups - Appropriate statistical tests to assess the outcomes - Measures of compliance reliable - Accurate outcome measures - Participants recruited from the same period of time - Participants recruited from the same population - Confounding adjusted in the analysis - Actual probability values (P values) reported	- Participants not blinded - Outcome assessors not blinded - Intervention allocation not concealed - Power analysis for sample sizes not conducted - Important adverse effects not explicitly described - Participants not randomized to different groups
Toliman et al., 2019²²
- Hypothesis described - Outcomes to be measured described - Patient characteristics described - Intervention described - Distributions of principal confounders described - Main findings described - Estimates of random variability provided - No patients lost to follow-up reported - No significant changes to health care that the participants received, compared to that the majority received - Similar lengths of follow-up for participants in different groups - Appropriate statistical tests to assess the outcomes - Measures of compliance reliable - Accurate outcome measures - Participants recruited from the same period of time - Participants recruited from the same population - Confounding adjusted in the analysis - Actual probability values (P values) reported	- Participants not blinded - Outcome assessors not blinded - Intervention allocation not concealed - Power analysis for sample sizes not conducted - Important adverse effects not explicitly described - Participants not randomized to different groups
Des Marais et al., 2018¹⁸
- Hypothesis described - Outcomes to be measured described - Patient characteristics described - Intervention described - Distributions of principal confounders described - Main findings described - Estimates of random variability provided - Patients lost to follow-up described - No significant changes to health care that the participants received, compared to that the majority received - Similar lengths of follow-up for participants in different groups - Appropriate statistical tests to assess the outcomes - Measures of compliance reliable - Accurate outcome measures - Participants recruited from the same period of time - Participants recruited from the same population - Confounding adjusted in the analysis - Actual probability values (P values) reported	- Participants not blinded - Outcome assessors not blinded - Intervention allocation not concealed - Power analysis for sample sizes not conducted - Important adverse effects not explicitly described - Participants not randomized to different groups - Participants lost to follow-up not taken into account
Lam et al., 2018⁵
- Hypothesis described - Outcomes to be measured described - Patient characteristics described - Intervention described - Distributions of principal confounders described - Main findings described - Estimates of random variability provided - Patients lost to follow-up reported - Participants asked to participate representative of the population which they were recruited from - No significant changes to health care that the participants received, compared to that the majority received - Similar lengths of follow-up for participants in different groups - Appropriate statistical tests to assess the outcomes - Measures of compliance reliable - Accurate outcome measures - Participants recruited from the same period of time - Participants recruited from the same population - Actual probability values (P values) reported	- Participants not blinded - Outcome assessors not blinded - Intervention allocation not concealed - Power analysis for sample sizes not conducted - Important adverse effects not explicitly described - Participants not randomized to different groups - Confounding not adjusted in the analysis - Participants lost to follow-up not taken into account
Phoolcharoen et al., 2018²³
- Hypothesis described - Outcomes to be measured described - Patient characteristics described - Intervention described - Distributions of principal confounders described - Main findings described - Estimates of random variability provided - No patients lost to follow-up reported - No significant changes to health care that the participants received, compared to that the majority received - Similar lengths of follow-up for participants in different groups - Appropriate statistical tests to assess the outcomes - Measures of compliance reliable - Accurate outcome measures - Participants recruited from the same period of time - Participants recruited from the same population	- Participants not blinded - Outcome assessors not blinded - Intervention allocation not concealed - Power analysis for sample sizes not conducted - Important adverse effects not explicitly described - Participants not randomized to different groups - Confounding not adjusted in the analysis
Senkomago et al., 2018¹⁹
- Hypothesis described - Outcomes to be measured described - Patient characteristics described - Intervention described - Distributions of principal confounders described - Main findings described - Estimates of random variability provided - Patients lost to follow-up reported - No significant changes to health care that the participants received, compared to that the majority received - Similar lengths of follow-up for participants in different groups - Appropriate statistical tests to assess the outcomes - Measures of compliance reliable - Accurate outcome measures - Participants recruited from the same period of time - Participants recruited from the same population - Actual probability values (P values) reported - Participants lost to follow-up taken into account in the analysis	- Participants not blinded - Outcome assessors not blinded - Intervention allocation not concealed - Power analysis for sample sizes not conducted - Important adverse effects not explicitly described - Participants not randomized to different groups - Confounding not adjusted in the analysis
Wong et al., 2018⁸
- Hypothesis described - Outcomes to be measured described - Patient characteristics described - Intervention described - Distributions of principal confounders described - Main findings described - Estimates of random variability provided - Patients lost to follow-up reported - No significant changes to health care that the participants received, compared to that the majority received - Similar lengths of follow-up for participants in different groups - Appropriate statistical tests to assess the outcomes - Measures of compliance reliable - Accurate outcome measures - Participants recruited from the same period of time - Participants recruited from the same population - Confounding adjusted in the analysis - Actual probability values (P values) reported - Important adverse effects explicitly described	- Participants not blinded - Outcome assessors not blinded - Intervention allocation not concealed - Power analysis for sample sizes not conducted - Participants not randomized to different groups - Participants lost to follow-up not taken into account in the analysis
Zhang et al., 2018⁹
- Hypothesis described - Outcomes to be measured described - Patient characteristics described - Intervention described - Distributions of principal confounders described - Main findings described - Estimates of random variability provided - Patients lost to follow-up reported - No significant changes to health care that the participants received, compared to that the majority received - Similar lengths of follow-up for participants in different groups - Appropriate statistical tests to assess the outcomes - Measures of compliance reliable - Accurate outcome measures - Participants recruited from the same period of time - Participants recruited from the same population - Confounding adjusted in the analysis - Actual probability values (P values) reported	- Participants not blinded - Outcome assessors not blinded - Intervention allocation not concealed - Power analysis for sample sizes not conducted - Important adverse effects not explicitly described - Participants not randomized to different groups - Participants lost to follow-up not taken into account in the analysis
Cremer et al., 2017²⁰
- Hypothesis described - Outcomes to be measured described - Patient characteristics described - Intervention described - Distributions of principal confounders described - Main findings described - Estimates of random variability provided - Patients lost to follow-up reported - No significant changes to health care that the participants received, compared to that the majority received - Similar lengths of follow-up for participants in different groups - Appropriate statistical tests to assess the outcomes - Measures of compliance reliable - Accurate outcome measures - Participants recruited from the same period of time - Participants recruited from the same population - Confounding adjusted in the analysis - Actual probability values (P values) reported	- Participants not blinded - Outcome assessors not blinded - Intervention allocation not concealed - Power analysis for sample sizes not conducted - Important adverse effects not explicitly described - Participants not randomized to different groups - Participants lost to follow-up not taken into account in the analysis
Obiri-Yeboah et al., 2017²¹
- Hypothesis described - Outcomes to be measured described - Patient characteristics described - Intervention described - Distributions of principal confounders described - Main findings described - Estimates of random variability provided - No patients lost to follow-up reported - No significant changes to health care that the participants received, compared to that the majority received - Similar lengths of follow-up for participants in different groups - Appropriate statistical tests to assess the outcomes - Measures of compliance reliable - Accurate outcome measures - Participants recruited from the same period of time - Participants recruited from the same population - Confounding adjusted in the analysis - Actual probability values (P values) reported	- Participants not blinded - Outcome assessors not blinded - Intervention allocation not concealed - Power analysis for sample sizes not conducted - Important adverse effects not explicitly described - Participants not randomized to different groups

From: HPV Self-Sampling for Primary Cervical Cancer Screening: A Review of Diagnostic Test Accuracy and Clinical Evidence – An Update

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HPV Self-Sampling for Primary Cervical Cancer Screening: A Review of Diagnostic Test Accuracy and Clinical Evidence – An Update [Internet].

Chao YS, McCormack S.

Ottawa (ON): Canadian Agency for Drugs and Technologies in Health; 2019 May 30.

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Table 5Strengths and Limitations of Clinical Studies using the Downs and Black checklist11

Table 5Strengths and Limitations of Clinical Studies using the Downs and Black checklist¹¹