Is Signature Size Associated With Organ Donor Designation on Driver's Licenses?

INTRODUCTION: Previous studies suggest that large signature size is associated with narcissistic characteristics. By contrast, organ donation is an indicator of altruism. Because altruism and narcissism may be viewed as opposites, we sought to determine if smaller signature size is associated with willingness to be an organ donor. METHODS: Using a cross-sectional study design, we reviewed the health records of 571 randomly selected primary care patients at a large urban safety-net medical system to obtain their demographic and medical characteristics. We also examined driver's licenses that were scanned into electronic health records as part of the patient registration process. We measured signature sizes and obtained the organ donor designation from these driver's licenses. RESULTS: Overall, 256 (45%) patients were designated as donors on their driver's licenses. Signature size averaged 113.3 mm(2) but varied greatly across patients (10th percentile 49.1 mm(2), 90th percentile 226.1 mm(2)). On multivariate analysis, donor designation was positively associated with age 18-34 years, non-black race, having private insurance, and not having any comorbid conditions. However, signature size was not associated with organ donor designation. CONCLUSIONS: Signature size is not associated with verified organ donor designation. Further work is needed to understand the relationship between personality types and willingness to be an organ donor.