Visual Analog Scale Patient Global Assessments May Be Confusing for Patients With RA

Interpretation of PGA-VAS instruments can be complex, particularly in the care of vulnerable populations.

Patients with rheumatoid arthritis (RA) have difficulty completing visual analog scale patient global assessments (PGA-VAS), which can lead to clinical misclassification of disease activity. This research was presented in a study recently published in Arthritis Care & Research. 

This cross-sectional, observational study included 300 individuals with RA who completed both the Multidimensional Health Assessment Questionnaire PGA-VAS and the Disease Activity Score assessing 28 joints PGA-VAS. In a follow-up questionnaire, 40% reported confusion with the PGA-VAS. This result was associated with lower health literacy and symptoms of depression. Fewer than 25% of participants followed natural progression in classifying model disease states or met criteria for the remission threshold in remission model responses, an effect that diminished with greater income and health literacy.

Participants scored remission and ranked model disease states as mild, moderate, or severe. Regression analyses were used to link clinical features with outcomes. The outcomes of this study included whether the PGA-VAS caused confusion, if a natural progression was followed in model disease states responses, and whether the threshold for remission was met. The threshold for this latter outcome was determined by Boolean criteria and simplified disease activity index-based criteria for remission.

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The study researchers concluded that “patients perceive difficulty with PGA-VAS, and do not reliably rate model disease state VAS. These patients are potentially at risk for disease activity misclassification because of literacy and other barriers in completing VAS.”

Two authors report receiving funding from UCB Pharmaceuticals. See reference for a full list of disclosures.

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Hirsh J, Wood P, Keniston A, et al. Limited health literacy predicts patient confusion about patient global assessments of disease activity and rheumatoid arthritis model disease states [published online June 28, 2018]. Arthritis Care Res (Hoboken). doi: 10.1002/acr.23692