Introduction

The emphasis on a person’s right to accept or refuse to participate in biomedical research reflects important ethical principles such as respect for human dignity and autonomy. Informed consent for research on humans usually incorporates five essential components: a) the capacity to consent, b) disclosure of all relevant information about the research, c) the prospective participants’ comprehension of this information for making an informed decision, d) the prospective participants’ freedom from all coercion, and e) explicit and formal consent by the participant, usually in writing (1, 2).

Informed consent is complex. It is one thing to get potential participants to sign a form indicating that they have been informed about a trial, but another to achieve a participant’s understanding. To make the decision, the participant has to fully understand the information provided. As Faden and Beauchamp (3) have suggested, this involves three stages: a) the transmission and reception of information, b) the comprehension of information, and c) the use of information in arriving at a decision.

The goal of the process of informed consent is to make sure that research participants achieve informed decisions and then implement them. But the interaction between the researchers and participants is nearly as important as the outcome of their discussions. The issue of informed consent therefore implies a sharing of information.

In some cultures, the belief system of potential research participants does not use the concepts and terms of modern medical science and technology to explain health and disease. Studies have provided examples of pervasive beliefs about diseases and causes of death such as sorcery, spirits and forbidden food. This is significant, because when people do not understand or accept scientific explanations of health and disease, the challenge of obtaining informed consent can be daunting (4). Are we really gaining informed consent from people who may not believe in the germ theory of disease?

More research is needed in the process of obtaining informed consent and whether participants actually understand the information given to them. We examined the process of informed consent in a group of clinical trial participants to assess their understanding of the study in which they were participating, and the relationship of their understanding with demographic characteristics such as age, gender and education.

Methodology and analyses

The study aims to assess the adequacy of understanding of the information by study participants.

The study involved participants enrolled in a clinical trial of an antiretroviral therapy (ART) in Nigeria. The ART clinical trial is a non-inferiority trial involving a new (generic) antiretroviral drug to be marketed within the country and a drug already approved and used in the treatment of HIV. At the time of the study, ART was available in some pharmacies in major cities of the country, but it cost US$200 for a complete course for a month and US$100 for a generic, which is beyond the reach of most HIV positive individuals in Nigeria. HIV patients in the country at the time of the study were mainly treated through five federal government centres that provided ART at a subsidised rate of US$10 per month. The patient information sheet and informed consent form for the ART trial indicated that it was a research study and explained the purpose of the research.

All 180 people enrolled in the clinical trial were invited to participate; 70 initially agreed and 18 more volunteered later. The 88 participants comprised 48.8 per cent of the persons enrolled in the study. Data were collected through a questionnaire.

The information leaflet given to participants in the ART trial was used to design the questionnaire. The questionnaire used both structured and unstructured questions. Some of the questions had an open format; this enabled us to assess the participants’ comprehension of technical information. These questions asked for explanations and could be answered in a variety of ways. The questionnaire was pre-tested on a sub-sample similar to our target sample. The researcher, together with a trained interviewer, administered the questionnaire. The questionnaire was administered to all 88 participants two months after they were enrolled in the ART trial.

The questions covered knowledge of four main categories: the aims of the research and eligibility of participants, the risks and benefits, the right to refuse participation and withdraw from participation, and the practical procedures of the research. The maximum scores were 4, 10, 4 and 7 respectively for the four categories, and the overall knowledge score was 25. Responses were evaluated and recorded as either right or wrong. Scoring was based on information given to the participants about the trial.

A mean knowledge score of the four categories was obtained. The following cut-offs were used: a score of 75 per cent meant excellent knowledge, 60-74 per cent was good knowledge, 50-59 per cent meant moderate knowledge, 30-49 per cent was poor knowledge, and 0-29 per cent meant extremely poor knowledge.

After scoring, the data were entered in a computer database and analysed with STATA software. Percentages of fully correct, partially correct and incorrect answers were used to evaluate the subjects’ understanding. Frequency distribution was generated for all variables and later for collapsed categories. A spearman rank correlation, student’s T-test and one-way ANOVA were done to test the relationship between understanding and the demographic variables of education, gender and socio-economic status.

Results and discussion

Of the 88 respondents, 51 were female and 39 were male. The mean age of the participants was 39.2 (range 26-62). The majority (73) were Christian and 55 were married at the time of the study (Table 1). Sixty-six were employed at the time of study with a high percentage of civil servants and people doing business. All the respondents had some education and 22 were university graduates.

The majority of the respondents (75) knew they were enrolled to participate in research and 13 thought they were involved in a treatment schedule. Fifty-seven participants reported that doctors explained the trial; the counsellors explained the research to 23 of the participants, and nurses explained it to eight participants.