Background/Purpose: The patient global assessment (PtGA) is a core domain used in RA composite disease activity (CDA) measures for trials and treat-2-target paradigms. The PtGA is asked differently, either referring to the patient’s global health or condition (PtGA-GH), or to their arthritis disease activity (PtGA-AR). Objectives of this study were to assess agreement between PtGA-GH vs. PtGA-AR ratings and between CDA indices calculated using both versions of the PtGA.

Methods: We included patients enrolled in the Canadian Early Inflammatory Arthritis Cohort (CATCH) study between 2011 and 2017 who met 1987 or 2010 ACR/EULAR criteria for RA and simultaneously completed both PtGA-GH and PtGA-AR using a 10 cm VAS (scored 0-10) at baseline, 6- and 12-months of follow-up. Descriptive statistics were used to summarize baseline cohort characteristics, PtGA ratings and CDA indices with differences compared using Wilcoxon-sign rank tests and chi-square tests. Agreement was assessed using intraclass correlation coefficients (ICC) for continuous measures and weighted kappa coefficients for categorical measures. Stratified analyses were also performed by age (older >65) and sex.

Results: Of 571 early RA patients who completed both PtGAs, 71% were female, 83% were white, 17% were current smokers, 17% were erosive, and 60% had completed high-school. Baseline mean(sd) age was 55(15), symptom duration was 5(3) months and comorbid conditions were 2(2). Agreement between PGA ratings, composite CDA measures and classification of remission using both PtGA-GH and PtGA-AR are summarized in Table 1. Mean(sd) PtGA-GH ratings were only marginally higher than PtGA-AR ratings and agreement was high between PtGA ratings at baseline and over the first year follow up (all ICCs > 0.8). Agreement in CDA scores calculated with either PtGA was even higher at baseline and over time (all ICCs > 0.95). There was also high concordance in classification of remission using either PtGA at all time points (all Kappa’s > 0.85). Results of stratified analyses showed that relative to men, women tended to report slightly higher differences in PtGA-GH vs. PtGA-AR (all p’s >0.0001) but overall agreement in PGA ratings, CDA scores and classification of remission was very high and similar in both sexes. Age stratified analyses, which reflects the comorbidies that increase with age, were similar to those in the whole sample.

Conclusion: Results from this large sample of early RA patients followed in a longitudinal study in typical practice settings, showed patients rated their PtGA-GH marginally higher their PtGA-AR, but this difference had minimal impact on composite disease activity indices and classifications of remission commonly used in patient care. These findings suggest common composite measures of RA disease activity can be calculated using either the PtGA-GH or PtGA-AR.

Table 1: Agreement PtGA Indices

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-patient-global-assessment-and-common-composite-disease-activity-measures-vary-minimally-when-patients-reflect-on-their-arthritis-or-their-global-health-results-from-the-canadian-early-arthritis-c/