Background: To determine whether altruism as reason for participation in research is independently associated with adherence to a medical regimen in a clinical trial.
Methods: Participants were 475 participants in the Women's Estrogen for Stroke Trial. Before randomization to estrogen or placebo, all women were questioned about reason for participation and baseline features that may contribute to adherence. Adherence was defined as completion of at least 80% of expected pill intake during the trial.
Results: Women who reported at least one altruistic reason for participation were more likely to be college educated, have a higher level of social support, and a better functional status. They were also more likely to be adherent to their study medication {155 of 212 (73%) vs. 158 of 253 (62.5%), P < .01}. On stratified analysis and multivariable regression, the relationship between altruism as reason for participation and adherence was independent of other sociodemographic, psychosocial, and clinical features (relative risk 1.17, Confidence interval 1.03-1.32).
Conclusion: Altruism may explain a small portion of the variation in adherence among research participants. This relationship may have implications for recruitment of participants in clinical research. The possible contribution of altruism to the relationship between adherence and outcomes in clinical trials is worthy of further investigation.