Health Literacy predicts incident foot ulcers after 4 years – the SHELLED cohort study

Aims/hypothesis: To determine whether health literacy is associated with an index diabetes-related foot ulcer (DFU). Methods: The SHELLED Study is a 4-year prospective study of people with diabetes aged over 40 with no history of DFU. The primary outcome was development of a first foot ulcer. Health Literacy was measured using the short form Test of Functional Health Literacy in Adults (s-TOFHLA) and nine domains of the Health Literacy Questionnaire (HLQ). Results: Of 222 participants, 191 (86.0%) completed the study, of whom 13 (5.9%) developed an incident ulcer. In multivariable models, every unit increase in S-TOFHLA was associated with a reduced odds of foot ulcer development by 6% (OR 0.94, 95% CI 0.88 to 0.99). Better scores on two HLQ domains reduced the odds of foot ulcer (actively managing my health (OR 0.23, 95% CI 0.08 to 0.65) and understanding health information well enough to know what to do (OR 0.39, 95% CI 0.19 to 0.78). This was independent of baseline risk for foot disease. Conclusions/interpretation: These data provide novel evidence that health literacy is an important clinical risk factor for index foot ulceration. This is an area of potential focus for research and development of educational programs or policy aimed at reducing development of incident foot ulceration.