Table 1 Studies included in the review of patients understanding of informed consent in clinical trials
From: The reality of informed consent: empirical studies on patient comprehension—systematic review
Author [year] | Country | Number of patients | Age | Subject of the study | Population | Timing | Aspects of IC explored in the study and percentage of correct answers | Level of education |
|---|---|---|---|---|---|---|---|---|
Ponzio [6] [2018] | Italy | 60 | 52.9 ± 11.7 | Neurology | Adult patients | ND | Purpose of the study 20.7–93.5% Blindness 58.6–89.7% Freedom to withdrawal 100% Confidentiality 29–93.1% Risk 6.9–100% Benefits 34.5–96.6% | ND |
Schumacher [7] [2017] | USA | 50 | 61 (35–85) | Oncology | Adult patients | Mean time 60 ± 51 Days after ICP for treatment (oncology) trial | Risk 20% Direct benefits 76% Freedom to withdrawal 90% Voluntary participation 90% | Less than high school diploma 9% High school diploma 41% Associate degree 13% Bachelor’s degree 26% Master’s degree or higher 11% |
Chu [8] [2012] | Republic of Korea | 291 | 36.4 ± 15.0 | Oncology Cardiology Endocrinology Gastroenterology Immunology Neurology Others | Adult patients | ND | Freedom to withdrawal 78.2% Compensation 43.4% Randomisation 49.8% Fulfilling inclusion criteria to be eligible 82.5% Approval of bioethics committee 78.7% Voluntary participation 53.6% | ≤ High school 28.9% ≥ College 71.1% |
Chaisson [9] [2011] | Botswana | 1835 | 33 | Infectious disease | Adult patients | Within 30 days after ICP | Purpose of the study 90–97% Placebo and blinding 64–65% Voluntary participation 69–77% Risk 87–94% Freedom to withdrawal 76–77% | No formal education 7% Primary school 28% Secondary school 59% Tertiary 9% |
Ellis [10] [2010] | USA/Mali | 171 89 700 | 30 (18–50) 27 (18–50) ND | Infectious disease (malaria vaccine) | Adult patients and parents or guardians | Directly after ICP | Freedom to withdrawal 93–98%1 Safety and side effects 48–85%1 | ND |
Minnies [6] [2008] | South Africa | 192 | 26 (16–44) | Infectious disease | Parents or guardians | Within 1 h after ICP | Reason to participate 85.4% Purpose of the study 80.6% Procedures 60.9% Duration of the study 66.3% Risks 79.2% Benefits 51.3% Voluntary participation 65.1% Confidentiality 73.3% Storage and use 82.9% | Grade ≤ 6 23.4% Grade 7–11 42.8% Grade ≥ 12 33.9% |
Bergenmar [11] [2008] | Sweden | 282 | 60 (32–82) | Oncology | Adult patients | Within max. 2 weeks after ICP | Voluntary participation mean 96.2 (13.2) Confidentiality mean 84.3 (26.2) Potential risks or discomfort mean 76.7 (28.2) Withdrawal criteria > 90% Randomisation > 80% Side effects > 10% | Compulsory school (1–9 years) 24% Senior high school (10–12 years) 29% University education (13–16 years) 38% Higher university education (> 16 years) 9% |
Bertoli [12] [2007] | Argentina | 105 | 56.3 ± 11.8 | Rheumatology | Adult patients | ND | Participant’s blinding 64.9% Investigator’s blinding 27.3% Freedom to withdrawal 77.8% Randomisation 10% Placebo 47–65.5%2 Confidentiality 52% | Illiterate 1.9% Elementary school (7 years of education) 48.6% High school 28.6% Higher educational degrees 19.0% |
Krosin [13] [2006] | Mali | 163 | ND | Infectious disease (malaria vaccine) | Adult patients | Within 2 days after ICP | Voluntary participation 57% Compensation 44% Withdrawal criteria 10% Withdrawal consequences 44% Randomisation and placebo 68% Side effects 7% Lay scientific knowledge 73% | Primary education 67% Literate to some degree 70% |
Criscione [14] [2003] | USA | 30 | 44.9 ± 9.8 | Rheumatology | Adult patients | 7–28 days after ICP | Voluntary participation 77% Freedom to withdrawal 63% Participant’s blinding 53% Investigator’s blinding 80% Randomisation 50% Placebo 87% Risk and safety 30% | Years of education, median 12.5 |
Pope [15] [2003] | Canada | 190 | 63 (22–84) | Cardiology, ophthalmology, rheumatology | Adult patients | 2 months to 5 years after ICP | Participant’s blinding 14–47%3 Investigator’s blinding 9–60%3 Randomisation 20–66%3 Placebo 13–49% 3 | Elementary school 18% High school 45% Higher education 36% |
McNally [16] [2001] | UK | 29 | 32 | Infectious disease | Parents or guardians | ND | Randomisation 75% Blinding 75% Placebo 64% | No formal education 18% ≥ Advanced “A” level 21% Ordinary “O” level 39% National vocational qualification 11% Certificate of secondary education 11% |
Itoh [17] [1997] | Japan | 32 | 58 (30–68) | Oncology | Adult patients | After ICP before drug treatment | Freedom to withdrawal 97% Right to therapeutic choice 88% | Elementary school 16% High school 47% Higher education 28% Unknown 9% |
Harrison [18] [1995] | USA | 175 | 37 (18–56) | Infectious disease (HIV vaccine) | Adult patients | Before ICP | Confidentiality 95–100%4 Side effects 83–100%4 Randomisation 68–96% 4 | ND |