Table 1.
Results from trials of written interventions to improve patient comprehension in informed consent
| Source | Study country |
N | Mean patient age (and range if specified) |
Patients’ education |
Procedure | Intervention | Elements of patient comprehension assessed |
Comprehension assessment tool |
Timing of patient comprehension assessment relative to informed consent consultation* |
Risk of bias for patient comprehension outcome† |
Results | Group favored‡ |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Straessle et al. (2011) | Switzerland | 185 | 54 y | 26% primary education, 37% apprenticeship, 24% secondary education, 12% university | Elective orthopedic surgery | Information form describing types of anesthesia, pre-operative instructions, recovery, and the role of the anesthetist (testing in 20 patients for comprehensibility, legibility, and completeness; reading level not specified) given to patients before the pre-anesthetic consultation versus standard care (control) | General knowledge about procedure | 3 items on a 17-item multiple choice questionnaire adapted from a validated measure (other questions pertained to patient satisfaction) | Immediately | Some concerns for bias | Percentage of correct answers 75% intervention vs. 62% control, P <0.01 | Intervention |
| Borello et al. (2016) | Italy | 70 | Mean age not specified, range 24 - 80 y | 50% did not complete high school, 26% completed high school, 23% college | Laparoscopic cholecystectomy | Standard verbal explanation using a simplified informed consent document with bulleted text and limited anatomical images (reading level not specified) in place of a standard informed consent document versus standard verbal explanation using a “standard text document” (control) | Risks, general knowledge about procedure | 9-item multiple choice questionnaire | Not specified | Some concerns for bias | 33.3% intervention vs 24.3% control answered all questions correctly, “no statistically significant difference" (no P value given) | Neither |
| Wong et al. (2016) | Canada | 60 | 55.8 y | 20% did not complete high school, 27 % completed high school, 49% with some college or trade school, 4% with some graduate school | Carpal tunnel release surgery | Single-sided, single page pamphlet detailing risks at a 7th grade reading level provided following standardized informed consent consultation (detailed, standardized discussion of potential complications) versus standard informed consent consultation alone (control) | Risks | Blinded research team member used standardized script to ask patients to recall risks via telephone | Delayed | Some concerns for bias | Number of risks recalled 1.33 (SD 1.21) intervention vs. 1.45 (SD 1.22) control, P = 0.73 | Neither |
| Aremu et al. (2011) | Nigeria | 50 | 43 y (range 16 - 76) | 52% high school or less, 48% some degree of postsecondary training | Mastoidectomy, tympanoplasty, nasal polypectomy, rhinotomy, maxillectomy, and laryngoscopy | Information handout addressing risks of the specific procedure (reading level not specified) in addition to verbal consent using a standard checklist of risks versus verbal consent using a standard checklist of risks only (control) | Risks | Telephone interview assessing recall of risks discussed | Delayed | Some concerns for bias | Unclear: overall risks correctly recalled reported as both 67% and 62% for intervention vs. 51% control "The difference was significant” (no P value provided) | Intervention |
| Finch et al. (2009) | England | 100 | 73.5 y | Not specified | Transurethral resection of the prostate | Informed consent using British Association of Urological Surgeons (BAUS) procedure-specific consent form including check boxes for frequently occurring risks (reading level not specified) versus informed consent using conventional Department of Health Type 1 consent form (control) | Risks, benefits, general knowledge about procedure | "Short, standardized questionnaire” | Early | High risk of bias | No overall score reported; no significant difference in “median estimation of risk” for 4 independently assessed risks, intervention group accurately predicted risk of redo at 10 years 50% of the time vs. 10% for control, P = 0.007 | Neither |
| Hong et al. (2009) | Canada | 100 | 42 y (range 20 - 68) | 60% no university, 40% university or higher | Rhinoplasty | Written pamphlet outlining the risks of the procedure (reading level not specified) in addition to oral dialogue with surgeons using a checklist of complications versus oral dialogue alone (control) | Risks | Recall of risks via telephone call with guided questions, answers recorded "on a standard set form" | Delayed | High risk of bias | Average risk recall 2.3 out of 5 intervention vs. 1.3 out of 5 control, P < 0.008 | Intervention |
| Khan et al. (2013) | England | 114 | Not specified | Not specified | Hand surgery | A4-sized document (8.27 × 11.69 inches) explaining risks (reading level not specified) in addition to standard verbal information versus standard verbal information only (control) | Risks | "A4 size questionnaire" | Delayed | High risk of bias | Mean percentage of risks recalled 85% intervention vs. 79% control, P = 0.1 | Neither |
| Alsaffar et al. (2016) | Canada | 49 | 49 y (range 27 - 77) | Not specified | Total thyroidectomy | Pamphlet provided at the beginning of the informed consent interview (reading level not specified) and discussed point-by-point in addition to verbal consent with a senior staff surgeon following a standardized script versus verbal consent with a senior staff surgeon following a standardized alone (control) | Risks | 12-item written multiple choice test | Delayed | High risk of bias | Overall correct score 80% intervention vs. 83% control group (no P value provided) | Neither |
| Smith a et al. (2012) | England | 119 | 62.1 y (range 18 - 99) | Not specified | Surgeries for traumatic upper or lower limb fracture requiring surgical fixation | 2-page written information leaflet with details about diagnosis, surgery, risks, post-op care, and rehabilitation (same as information discussed verbally, reading level not specified) given in addition to standard, structured verbal information versus standard, structured verbal information alone (control) | Risks | "Standardized, structured self-administered questionnaire " | Delayed | High risk of bias | Mean score 64% intervention vs. 41% control, P = 0.0014 | Intervention |
| Gangol et al. (2010) | Nepal | 116 | 44.1 y | 7.0% primary (1 to 3 classes), 32.5% secondary (4 to 10 classes) 11.4%, higher (>10 classes) | Elective cholecystectomy | Information leaflet written in Nepali with information about indications, anesthesia, difference between laparoscopy versus open procedure, post-op pain control and diet, and complications (reading level not specified) given in addition to standard verbal counseling versus standard verbal counseling only (control) | Unclear/ not specified | 10 standard questions asked in interviews; each answer scored as 2 (understood well), 1 (satisfactory understanding), or 0 (poor understanding) | Not specified | High risk of bias | Mean score 14.98 out of 20 intervention vs. 8.05 out of 20 control group and level of understanding "good" (score 51-75%) or "satisfactory" (score >75%) in 76.3% intervention vs. 18.2% control, P = 0.000 | Intervention |
*
Immediately: within 1 hour of informed consent consultation; early: >1 hour but <24 hours of informed consent consultation, delayed: ≥ 24 hours after informed consent consultation
†
Assessed using the Cochrane Risk of Bias 2.0 tool, see Table 7 for details
‡
If a study reported an improvement in patient comprehension on a single item or multiple items of the comprehension assessment but if overall score did not improve, we considered neither or no group to be favored