Patient assessments of disease activity (PtGA) and general health (GH) measured by visual analog scale (VAS) are widely used in rheumatoid arthritis (RA) clinical practice and research. These require comprehension of the question's wording and translation of disease activity onto a written VAS, which is problematic for patients with limited health literacy (HL) or difficulty completing forms. This study's objective was to validate verbally administered versions of patient assessments and identify factors that might explain discrepancies between verbal and written measures.
We enrolled patients with RA at the Denver Health rheumatology clinic (n = 300). Subjects were randomized to complete the traditional written PtGA and GH and one of the verbal assessments. Subjects provided a verbal numeric response after reading the question, having the question read to them in person, or hearing the question over the phone. Spearman and Lin correlations comparing written and verbal assessments were determined. Multivariate logistic regression was performed to explain any discrepancies.
The instruments administered verbally in-person showed good, but not excellent, correlation with traditional written VAS forms (Spearman coefficients 0.59 to 0.70; p < 0.001 for all correlations). Twenty-three percent of subjects were unable to complete 1 of the written VAS assessments without assistance. HL predicted missing written data and discrepancies between verbal and written assessments (p < 0.05 for all correlations).
Providers should use verbal versions of PtGA and GH with caution while caring for patients unable to complete traditional written version. Limited HL is widely prevalent and a barrier to obtaining patient-oriented data.