Association of Health Literacy and Numeracy With Lupus Knowledge and the Creation of the Lupus Knowledge Assessment Test.

Objective: Limited health literacy and numeracy are associated with worse patient-reported outcomes and higher disease activity in systemic lupus erythematosus (SLE), but which factors may mediate this association is unknown. We sought to determine the association of health literacy and numeracy with SLE knowledge.

Methods: Patients with SLE were recruited from an academic center clinic. Participants completed validated assessments of health literacy (Newest Vital Sign [NVS]; n = 96) and numeracy (Numeracy Understanding in Medicine Instrument, Short Version [S-NUMI]; n = 85). They also completed the Lupus Knowledge Assessment Test (LKAT), which consists of 4 questions assessing SLE knowledge that were determined through consensus expert opinion for their wide applicability and importance related to self-management of the disease. Descriptive statistics and multivariable logistic regression modeling were used to analyze the results.

Results: In our SLE cohort (n = 125), 33% (32/96) had limited health literacy and 76% (65/85) had limited numeracy. The majority correctly identified that hydroxychloroquine prevented SLE flares (91%); however, only 23% of participants correctly answered a numeracy question assessing which urine protein to creatinine (UPC) ratio was > 1000 mg/g. The mean LKAT score was 2.7 out of 4.0. Limited health literacy, but not numeracy, was associated with lower knowledge about SLE as measured by the LKAT, even after adjusting for education.

Conclusion: Patients with SLE with limited health literacy had lower knowledge about SLE. The LKAT could be further refined and/or used as a screening tool to identify patients with knowledge gaps. Further work is needed to improve patients' understanding of proteinuria and investigate whether literacy-sensitive education can improve care.