Abstract
BACKGROUND: Adherence to immunosuppressive therapy is crucial for successful outcomes in solid organ transplantation. Tacrolimus intra-patient variability (%CV) is a validated marker of adherence and has been associated with graft outcomes. Health literacy (HL), a modifiable factor, may influence this variability, but its role remains unexplored. METHODS: We conducted a prospective observational study including adult kidney, liver, and lung transplant recipients receiving tacrolimus. HL was assessed using the Short Test of Functional Health Literacy in Adults (S-TOFHLA); a score <23 indicated insufficient HL. Tacrolimus %CV was calculated over 6 months post-discharge. Linear regression models, adjusted for sociodemographic variables, evaluated the association between HL and %CV. RESULTS: Ninety-eight patients were included (kidney: n = 38, liver: n = 24, lung: n = 36). Patients with insufficient HL had higher %CV than those with sufficient HL (31.5% vs. 16.1%, p < 0.05). HL remained independently associated with %CV after adjusting for age and transplant type (β = -1.60, SE = 0.17, p < 0.05). The final model explained 53% of %CV variability. CONCLUSIONS: HL is independently associated with tacrolimus variability. HL screening and targeted educational interventions may help improve medication stability and long-term transplant outcomes.