Background/Purpose: Patient (PtGA) and physician (MDGA) global assessment of disease activity are standard outcome measures used to ascertain physician and patient subjective perception of disease activity in rheumatoid arthritis (RA). Given that the PtGA and MDGA measure the same construct from two different perspectives, assessing their discordance may provide valuable insight on patient and physician differences with respect to the relative importance placed on specific disease parameters.

Methods: BioTRAC is an ongoing Canadian registry of patients initiating treatment with infliximab or golimumab as first biologics. PtGA and MDGA were measured at baseline using a 10cm VAS. Using tertiles of the baseline MDGA-PtGA distribution every patient was classified as having higher assessment than the physician (range: -10.0 to -0.5), agreement (range: -0.4 to 1.1) or lower assessment than the physician (range: 1.2 to 8.0).

Results:

841 patients with baseline data for both PtGA and MDGA were included. Among these 623 (74.1%) were female, mean age was 57.0 yrs and mean disease duration was 9.8 yrs. Mean (SD) PtGA and MDGA were 6.1 (2.4) and 6.5 (2.1), respectively, and the mean (SD) PtGA – MDGA was 0.4 (2.4) with a median of 0.3; for 6.4% of the patients the PtGA-MDGA was nil.

Significant differences between patients with lower, equal or higher assessment relative to the physician assessment were identified. When compared to patients with higher PtGA relative to MDGA, patients with lower assessment of their disease activity had lower morning (AM) stiffness, pain, and HAQ-DI but higher SJC (Table 1). AM stiffness, SJC, TJC, and HAQ-DI were highest in patients with PtGA-MDGA agreement. Age, gender, and SJC/TJC ratio were not different for the three groups. Linear regression using backwards selection identified pain (P<0.001), SJC (P<0.001), and HAQ-DI (P=0.056) as independent predictors of PtGA-

Table 1: Patient Baseline Characteristics by Degree of Difference Between MDGA and PtGA
Mean (SD)	Lower PtGA vs. MDGA1	Higher PtGA vs. MDGA2	P-Value3
Age: Years	56.9 (13.8)	57.2 (13.2)	0.815
Disease Duration: Years	9.0 (8.3)	10.0 (10.5)	0.478
AM Stiffness: min	62.0 (44.5)	70.7 (43.2)	0.019
Pain: VAS mm	42.0 (22.4)	67.4 (21.2)	<0.001
SJC-28	11.1 (7.0)	9.1 (6.4)	<0.001
TJC-28	12.0 (8.1)	11.4 (7.3)	0.326
SJC/TJC	1.1 (1.1)	1.1 (1.6)	0.805
HAQ-DI	1.42 (0.73)	1.69 (0.65)	<0.001
1 MDGA-PtGA range: 1.2 to 8.0 2  MDGA-PtGA range: -10.0 to -0.5 3  P-Value was assessed with a t-test for independent samples

MDGA.

Conclusion: The relative importance of morning stiffness, pain, HAQ, and SJC in assessing disease activity may be different between patients and physicians. These results have implications for development of assessment tools that better represent both patient and physician perspectives of disease activity.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/identification-of-four-parameters-that-drive-the-discordance-between-the-patient-and-physician-global-assessment-in-rheumatoid-arthritis/