Risk perception and its role in attitudes toward blood transfusion: a qualitative systematic review.

Despite improvements in blood safety making transfusion a much safer clinical procedure, the general public still perceives it as risky. We systematically reviewed available literature to examine evidence regarding the reasons and causes behind this perception. Electronic databases including PubMed, Cochrane Library, and EMBASE for literature dating back to the 1980s were searched. Eligible studies collected information on blood recipients' demographics, measures of risk domains (sets of values that risks encompass), and general knowledge of blood transfusion in terms of risks and benefits. Each study was assessed for quality of data, research method, and relevant findings. A scoring system was used to subjectively rate the overall quality of each study. Each study was reviewed for its method of data collection and information abstracted on hazards and conceptual dimensions used to measure risk. Risk perception between blood transfusion and other hazards including alternatives to transfusion were compared. Fifteen studies met the inclusion criteria, all of which were conducted outside the United States, with most of the studies published more than 10 years ago and conducted by only 3 research groups. Five studies were rated as being very good, four good, five fair, and one of poor quality. The finding of the studies consistently show that objective or raw knowledge is not correlated with risk perception, but subjective or calibrated knowledge is. Thus, it is what people think they know rather than what they actually do know that influences risk perception of transfusion. Of the 3 common conceptual domains-dread, unknown risk, and benefits-blood transfusion was found to be of intermediate dread, intermediate unknown risk, and most beneficial compared with other hazards. Donated blood was found to have lower perceived risk than all other alternatives to transfusion, except for use of autologous blood. There is a lack of recent studies on allogeneic transfusion. However, the more recent studies show that perceived high risk is still prevalent in the general public. The available risk perception studies suggest that although blood transfusion is safe, elevated risk perception of infections persists. Studies of the US population are needed to better understand the influence of both psychological and scientific factors.