“Too Good to Be True?” Social Desirability Bias in Age-Related Patterns of Self-Reported Medication Adherence Among Patients with Atrial Fibrillation
Objective: To investigate whether social desirability bias contributes to the paradox of older adults reporting high medication adherence despite a greater risk of non-adherence due to polypharmacy and comorbidities.
Methods: We analyzed cross-sectional data from 308 anonymized adults with atrial fibrillation (AF) from the UK (n=100), the US (n=103), and Germany (n=105). Participants completed the Adherence Assessment Questionnaire (AAQ), a validated self-report instrument that includes a two-item social desirability scale.
Results: The sample had a mean age of 67.0 years (SD: 13.2), and 33.8% were female. Increasing age and higher social desirability scores were associated with lower odds of reporting non-adherence (OR = 0.97, 95% CI: 0.94-0.99, p = .009 and OR = 0.80, 95% CI: 0.64-1.00, p = .051, respectively). The age-by-social desirability interaction was marginal in the binomial model (OR = 0.98, 95% CI: 0.96-1.00, p = .105), but significant in ordinal (p < .001) and linear (p = .002) regressions. The moderation analysis (p = .016) confirmed that social desirability bias strengthened the association between age and adherence. No country-level differences were observed.