By Godin, Gaston Belanger-Gravel, Ariane; Gagne, Camille; Blondeau, Danielle
Context-The shortage of organs for transplantation has led public health authorities to invest significant efforts in the promotion of organ donation. Objective-To identify factors predictive of signed consent for posthumous organ donation by using the theory of planned behavior.
Participants and Design-A random sample of 602 adults completed a questionnaire at baseline, and behavior was self-reported 15 months later.
Results-Logistic regression indicated that intention, perceived behavioral control, moral norm, and past behavior were factors predictive of consent for posthumous organ donation. Participants’ perceived behavioral control, past behavior, and moral norm were also predictive of intention to sign, but attitude and perceived barriers were 2 additional determinants. Finally, anticipated regret and knowledge of persons who had made an organ donation were 2 moderators of the intention-behavior relationship.
Conclusion-Overall, the results showed that intention is an important determinant of signing the organ donor’s consent sticker and also highlighted that moral consideration and perceived difficulties could be 2 potential avenues for designing interventions. (Progress in Transplantation. 2008;18:109-117)
In Canada, as in many other countries, the gap between the number of organs needed for transplants and the number of organs available is increasing.1 For those waiting for an organ, this shortage has dramatic consequences on quality of life and life expectancy.2 Among the strategies used to increase organ donation, offering financial incentives and applying presumed consent3,4 have been suggested. From an ethical point of view, however, these financial and juridical strategies are questionable, and they are not allowed in Canada.57 Thus, public health practitioners must rely on educational interventions or promotional campaigns to promote organ donation. In Quebec, a province of Canada, there are 2 major ways to consent to posthumous organ donation: (1) signing the organ donors register of the Chambre des Notaires du Quebec [Notary Chamber of Quebec] and (2) signing the organ donor’s consent sticker when renewing the health insurance card.
Much of the scientific literature on organ donation has focused on the study of willingness/intention to register as organ donors. In general, willingness to donate is linked to a set of salient beliefs (eg, religious, cultural, altruistic, and normative) mediated by attitude toward becoming a donor.8 However, according to these authors, longitudinal studies based on strong theoretical foundations are needed. Likewise, many authors argue that the lack of theory-based studies may provide a potential explanation for the limited success of interventions aimed at promoting health-related behavior.9
More recent studies based on Bandura’s social cognitive theory10 suggest that past behavior, as well as the perception of positive and social outcomes and selfefficacy, should be considered to increase willingness to sign as an organ donor.11,12 Along the same line of thought, attitude, subjective norm, and perceived behavioral control, 3 variables of the Ajzen theory of planned behavior (TPB),13 as well as moral norm, were additional determinants of intentions related to organ donation in adults.14 Notwithstanding these findings, in a recent prospective study, researchers documented that a gap may exist between psychological predispositions toward organ donation and action.15 Indeed, they observed that many individuals who were willing to donate organs did not obtain their organ donor cards.
This lack of consistency between intention and subsequent behavior has been observed for several healthrelated behaviors.16 One explanation for this phenomenon could be the moderating effect of certain variables on this relationship. Previous studies on the moderating effect suggest that the intention-behavior relationship could be modulated by variables such as past behavior, anticipated regret, moral norm, and age.16-19 In the context of organ donation, however, only the moderating effect of religious beliefs has been documented.15
Thus, the aims of this study were (1) to identify the factors predicting the signing of the organ donor’s consent sticker among the general population in Quebec in reference to the TPB and (2) to test potential moderators of the intention-behavior relationship.
Theoretical Framework
In the present study, an extended version of the TPB was adopted (see Figure). According to the TPB, the immediate determinant of behavior is the intention to act. This intention is influenced by 3 main factors: attitude, subjective norm, and perceived behavioral control. Perceived behavioral control is defined as the degree of ease or difficulty with which a behavior can be adopted and can also directly predict behavior in parallel to intention when the behavior under study is not under volitional control (ie, when the adoption of the behavior requires skills, abilities, and resources). Attitude designates the individual’s favorable or unfavorable position toward adopting a specific behavior. Subjective norm corresponds to the subject’s perception of the level of approval or disapproval of important people or groups of people with respect to adoption of the behavior.
In the present study, additional variables known to contribute to either the prediction of behavior or intention also were considered. For instance, perceived barriers, anticipated regret, and moral norm were included in the theoretical framework (see Figure).20-22 Anticipated regret refers to an individual’s beliefs regarding the degree of regret, tension, or preoccupation one would feel if the targeted behavior were not adopted. Moral norm measures the sense of personal obligation toward adopting the behavior. It may be viewed as an expression of the core self, that is, individuals referring to their personal values and principles of conduct when deliberating the adoption of the behavior. Related to this latter variable, and based on previous research on ethics-related behaviors, constructs of autonomy, beneficence, and justice have been identified as subdimensions explaining moral norm.23 Beneficence is defined as “an action done to benefit others.”24(p166) More precisely, the “principle of beneficence refers to a moral obligation to act for the benefit of others.”24(p166) In other words, beneficence is associated with promoting the well-being of others. It is also related to the concept of nonmaleficence, which refers to the principle of not hampering others, of not causing them any harm or distress, of avoiding hurting them. Autonomy is the capacity of individuals to govern their lives and make their own choices. Finally, justice comprises 2 principles: commutative and distributive justice. These concepts are based on the recognition that all humans are equal and that social and natural imbalances must be corrected.
Finally, past behavior (eg, to have signed one’s card in the past), sociodemographic characteristics (eg, age, sex, education level, and marital status), and personal experience with organ donation such as knowing someone waiting for organ donation, knowing someone who received an organ, knowing someone who had made an organ donation, and knowing how to manifest consent to organ donation were considered, although their effect should be mediated through one or more of the main psychological factors explaining intention and predicting behavior.25
Materials and Methods
Population and Sample
The population targeted by this study was made up of individuals aged 18 years or older, living in Quebec, and likely to renew their health insurance cards in the coming year. A total of 2018 individuals were reached by phone by using a random digit number technique for the recruitment. Interviews were conducted by a firm specializing in telephone surveys. Before the questionnaire was completed, the purpose of the study, the right to refuse participation without consequence, and the confidentiality of responses were discussed. Among individuals reached, 918 (45.5% of participation rate) agreed to complete the questionnaire at baseline, but 30 did not agree to be contacted again for a follow- up on their behavior. Thus, among the 888 respondents who consented to be phoned again, a total of 625 respondents were successfully interviewed at follow-up. The others could not be reached or refused to participate. Also, 23 respondents were excluded because too much data was missing. Compared with the respondents included in the analysis (N = 602), those who were excluded were mainly male. No other significant differences were observed with respect to sociodemographic and psychosocial variables. This study was approved by the local university ethics committee.
Data Collection Procedure
At baseline, the interviews were conducted by a firm specializing in telephone surveys. The questionnaire was completed for those who agreed to participate. On average, this procedure lasted 12 minutes. At the end of the interview, respondents were invited to consent to be contacted by telephone 15 months later. At follow-up, respondents were asked if they had signed and applied their organ donor’s consent stickers on the back of their health insurance cards upon renewal (yes/no).
Questionnaire The questionnaire was developed following the guidelines specified by Ajzen and Fishbein26 and Godin and Kok,27 that is, the formulation of theoretical constructs (etic dimension) based on the beliefs and perceptions of the population under study (emic dimension). Behavior was defined as signing the organ donor’s consent sticker when renewing the health insurance card. The quality of the questionnaire was first verified among 10 individuals in the general population. They were asked to provide feedback and comments on item wording and clarity of questions; some modifications were made to the initial version of the questionnaire. Then, a 2-week test-retest reliability study was conducted among 53 respondents representative of the target population to determine internal consistency (Cronbach alpha coefficient) and temporal stability (intraclass coefficient). Items of the psychosocial variables, as well as their psychometric values, are presented in Table 1. Items of the subdimensions of moral norm that is autonomy (4 items, alpha= .81), beneficence (7 items, alpha = .96) and justice (4 items, alpha = .90) are described elsewhere.23
Statistical Analysis
A hierarchical logistic regression was performed to identify determinants of behavior (signing or not signing the organ donor’s consent sticker). Because the distribution of data was skewed, each variable was dichotomized at the median value. For the prediction of behavior, intention and perceived behavioral control were first entered into the model. Then, moral norm, anticipated regret, perceived barriers, and past behavior were included. Because the distribution of the dependent variable was skewed, a similar approach was used for the prediction of intention.
First, attitude, subjective norm, and perceived behavioral control were entered into the model. Next, moral norm, anticipated regret, and perceived barriers were added, followed by the sociodemographic variables and past behavior. For the preceding analyses, all potential predictors related at P
The moderating effect of some variables on the intention- behavior relationship was tested by using a 3-step hierarchical regression analysis.29-10 To test the independent contribution of each potential moderator (ie, moral norm, anticipated regret, the 3 ethical subdimensions of moral norm, past behavior, sociodemographic variables, and variables related to personal experience with organ donation), a model including the significant predictors of behavior identified in the previous steps was tested for each moderator and their interaction term. A moderating effect was detected if the interaction term reached statistical significance (P= .10) and if the log likelihood ratio indicated that the model was significantly improved (P
Results
Description of the Sample
The mean (SD) age of the sample (N = 602) was 41.6 (14.2) years. Most respondents were married (59.7%), were women (60.1%), and had completed at least some college education (70.1%). In this sample, 71.1 % of the respondents had signed a card to consent to organ donation. Results also showed that 90.0% of the respondents knew that they could consent to organ donation by signing the organ donor’s consent sticker. Finally, the majority of the respondents reported having very good or excellent health (69.3%).
Determinants of Behavior
Among the respondents, 391 (65.0%) had signed their organ donor’s consent sticker at the followup. For the prediction of behavior, 4 variables made a significant contribution: past behavior (P
Determinants of Intention
The median score of intention was 3.67. The logistic regression model showed that the following factors, in order of decreasing importance, were predictive of intention to consent to organ donation: past behavior of signing the organ donor’s consent sticker (P
Moderation Effects
Tests for moderating effect of the intentionbehavior relationship revealed that anticipated regret (P= .05) and knowing someone who had made an organ donation (P= .05) were 2 independent significant moderators of this relation (see Table 2, Models 3a and 3b). None of the other interaction terms were significant (data not shown). The intention-behavior relationship was verified separately for those who differed in their level of anticipated regret and for those who reported knowing or not knowing someone who had donated their organs. The results of these analyses are presented in Table 4. Contrary to expectation, the intentionbehavior relationship was weaker among those who had a higher level of anticipated regret. Deeper analysis of the relationship indicated that this was mainly due to the behavior of low intenders (chi^sup 2^= 13.08; P
A final model of behavior that included the 2 interaction terms was tested. All variables previously found to be significant predictors of behavior remained significant (see Table 2, Model 4), although moral norm (P = .05) was not significant but remained near significance.
Discussion
This prospective study provides useful information on the factors predicting behavior (not only intention) and potential moderators of the intention-behavior relationship. More specifically, the results showed that signing the organ donor’s card is predicted by intention, perceived behavioral control, moral norm, and past behavior, whereas the intention-behavior relationship is moderated by anticipated regret and knowing someone who has made an organ donation.
The contribution of intention and perceived behavioral control in the prediction of signed consent to organ donation is congruent with Ajzen’s TPB, and the importance of those factors as determinants of health-related behaviors has been confirmed in several meta- analyses.27,31 Past research, essentially based on cross-sectional studies, has placed much emphasis on the study of intention (eg, willingness) to consent to register for posthumous organ donation, but has not given much attention to its predictive power. The present longitudinal study confirms the important role of intention in predicting signed consent for posthumous organ donation, and our findings are well aligned on a quantitative summary of a number of meta-analyses showing that a significant portion of the variance in behavior is accounted for by intention.16 Thus, our results highlight the relevance of understanding determinants of intention, as this information can guide the development of interventions and promotional strategies to increase the motivation of potential organ donors.
To our knowledge, this study is the first to report that perceived behavioral control is a determinant of signed consent for posthumous organ donation. Recent research indicates that perceived behavioral control is actually an amalgamation of 2 constructs: perceived difficulty and perceived control.32,33 In the present study, the concept of perception of control referred to the perceived difficulty dimension. Thus, individuals who evaluated providing consent for posthumous organ donation as a simple act were more likely to sign the sticker of their health insurance cards at renewal.
Moral norm was also identified as a direct predictor of behavior. Within social cognitive theories, it has been documented that moral norm adds to the understanding of intention31,34 and certain healthrelated behaviors.35,36 However, the vast majority of studies that showed an impact of moral norm on intention did not show a similar impact on behavior, at least when intention was included in the analysis. Although the current study does not provide explanations for this direct effect, an attempt to conceptualize the way in which moral norm impacts on behavior can be found in the norm- activation theory (NAT).37 Schwartz and Berkowitz37(p231) argue that it is likely that many individuals adopt specific behaviors by conviction; that is, because they feel a moral obligation to adopt them: “Individuals sometimes act in response to their own self- expectations, their own personal norms.” According to NAT, a given behavior is adopted not because of the expected outcomes of performance, but for more internalized feelings that can be captured by the concept of moral norm. Schwartz and Berkowitz proposed that these personal norms are not experienced as intentions, but as feelings of moral obligation, and so can directly influence behavior. Obviously, signed consent for posthumous donation also involves dimensions other than a more rational statement of intention and perceived behavioral control. Similar to what has been observed for other altruistic behaviors,38,39 past behavior was an important determinant of signed consent for posthumous organ donation. Although past behavior is not a modifiable target for intervention, it is likely that those who signed their cards in the past will sign them again in the future. To date, the mechanism by which past behavior influences future behavior is not well understood. One possible explanation is the development of a habit; that is, as the past behavior increases, the influence of this variable on future behavior also increases.40 However, since the frequency of renewal is relatively modest in the present context (ie, about every 4 years), it would be difficult to accept that the frequency of past behavior exerted such an effect. The present study does not provide specific explanations for this effect. Results support the relevance of offering specific interventions aimed at promoting willingness to register as a potential posthumous organ donor in adolescence to develop lifetime habit in youth. Examples of such successful interventions can be found in scientific literature.41-43
Because intention is a significant predictor of behavior, the examination of the determinants of this variable helped to identify promotional strategies to increase the motivation of potential organ donors. As was the case for the prediction of behavior, perceived behavioral control and past behavior were determinants of intention; these 2 factors were discussed earlier. Additional factors explaining intention were attitude, perceived barriers, and moral norm (or beneficence).
Most scientific reviews of willingness to consent to become a potential organ donor have reported that attitude is one of the main factors explaining this decision.8,44 The present findings are no exception to this conclusion and confirm its contribution to explaining intention. This suggests that persuasive messages about the positive consequences of organ donation still represent an interesting approach to promoting this behavior. Nonetheless, attitude is not alone, and other variables share the same weight in the explanation of intention. According to Ajzen,13 perceived behavioral control should mediate the effects of perceived barriers on intention. However, a recent meta-analysis found significant relationships between perceived barriers and intention after perceived behavioral control had been taken into account.20 The results of this study support this hypothesis. Consequently, perceived barriers enhance the level of explained variance in intention and should be considered in future studies aimed at predicting the intention of individuals toward organ donation. Among the barriers identified was the fear of one’s body being mutilated and the fear of not having done everything possible to save one’s life. These 2 items are quite similar to the perceived negative outcomes of registering as an organ donor reported among Dutch adolescents.11,12 Obviously, such barriers should be considered in future promotional strategies. In particular, special attention should be given to explaining legal procedures that must be followed for the determination of death before organs are taken from the dead body.
Interestingly, the present study showed that beneficence, a subdimension of moral norm, was predictive of intention beyond the global assessment of moral norm or other psychosocial determinants. Hence, it seems important to assign importance to ethical variables in future research to study behavior that has a moral connotation. The contribution of beneficence to the explanation of intention confirms the view of Radecki and Jaccard8 that the person who agrees to sign his/her organ donor card is actively involved in an altruistic act. In the context of organ donations, a person could sign a donor card with the altruistic goal of doing a good deed for another person with the intention of improving that person’s quality of life. From a practical point of view, this suggests that more interventions should promote the idea of personal commitment to donate by signing the donor card. In this regard, persuasive messages encouraging individuals to make a decision regarding posthumous donation are effective.45 It might be suggested that focusing on the potential positive effects of organ donation on others’ lives (eg, saving a mother of 3 children or saving a child’s life) could stimulate individuals to consent to organ donation.
In the present study, anticipated regret and knowing someone who donated 1 or more organs were identified as moderators of the intention-behavior relationship. We observed a surprising effect for the moderating effect of anticipated regret: the intention-behavior relation was weaker among those who anticipated regret if they did not sign their organ donor’s consent stickers than among those who did not anticipate regret. The analysis of this relationship showed that this effect was attributable to the low intender group. Indeed, low intenders who did not anticipate regret did not provide consent for posthumous organ donation. On the other hand, low intenders who anticipated regret presented more variation in behavior at follow- up; that is, a significant proportion signed their cards at follow- up in spite of their negative intention to do so. In a recent study46 of adolescent smoking initiation, researchers also observed a similar moderating effect of anticipated regret. They found that participants who anticipated regret about starting smoking, although they had the intention to start smoking, were not consistent with their initial intention and were more likely not to smoke at follow- up. In the context of the present study, this result suggests that the absence of anticipated regret supports the decision not to sign, whereas the presence of anticipated regret creates ambiguity in the decision. As a consequence, someone who anticipates regret is more likely to sign a consent for posthumous organ donation. This result should, however, be confirmed in future studies. For intervention purposes, it might be suggested that a specific message such as: “Don’t regret not doing it, just sign it to give life!” could be used to invite individuals to sign their organ donor’s consent stickers on the back of their health insurance cards.
Knowing someone who has donated 1 or more organs was the other moderator identified in the present study. Thus, knowing someone who has donated organs is likely to make the need for organ donations more salient. This finding offers an avenue for intervention, as suggested by recent findings.43,47 For instance, Smits et al43 showed that an intervention provided by kidney transplantation patients was successful in encouraging adolescents to make a well- considered choice with regard to registering as potential posthumous organ donors.
A few limitations of this study must be noted: the response rate, social desirability bias, and cultural factors. The response rate does not allow the results to be generalized to the general population, and it is possible that respondents were more positive toward the topic of the study than one would expect from the general population. Those who refused to participate might have responded differently and most likely more negatively than the cohort of this study. For instance, 65% reported having signed to provide consent for posthumous organ donation, a proportion much higher than the known proportion in the population (at about 28%).48 All possible precautions were taken to avoid social desirability bias, but this bias still might have affected some participants’ answers. Finally, diverse cultural factors such as religious beliefs44 or race49 can affect organ donations. The present study was conducted among a predominantly white and Catholic population. In other words, a cultural context different from the study setting might have revealed a different interplay of factors.
To conclude, this prospective study provides a better understanding of the factors predicting behavior. In particular, it shows that intention is an important determinant of signing to provide consent for organ donation, whereas moral considerations influence both behavior and intention to provide consent for posthumous organ donation. Overall, the present study provides interesting avenues for designing interventions aimed at promoting signed consent for posthumous organ donation.
Acknowledgments
We thank Leo-Daniel Lambert for his technical assistance in the statistical analysis and Isabelle Martineau for project coordination.
Financial Disclosures
Gaston Godin holds a Tier 1 Canada Research Chair in Health Related Behaviour, Laval University. This work was supported by a grant from the Canadian Institutes of Health Research (grant no. 43932).
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Gaston Godin, PhD, Ariane Belanger-Gravel, MSc, Camille Gagne, PhD, Danielle Blondeau, PhD
Laval University, Quebec, Canada
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