Influence of the different “patient global assessment” formulations on disease activity score by different indices in rheumatoid arthritis

Abstract

Patient global assessment (PGA) is included in almost all rheumatoid arthritis (RA) composite disease activity indices and definitions of remission. However, different PGA formulations exist and are used interchangeably in research and clinical practice. We investigated how five different PGA formulations used in four disease indices affect the remission rates. This was an ancillary analysis of data from a cross-sectional study in patients with RA. The data comprised the following: 28-joint counts, C-reactive protein, and five PGA formulations. Remission rate variation was assessed using five PGA formulations in each index (ACR/EULAR Boolean, CDAI, SDAI, and DAS28-CRP). PGA agreement was assessed by the following: Pearson's correlation; Bland-Altman plots; paired samples t test; and establishing the proportion of patients who scored (i) all formulations within an interval of 20 mm and (ii) each formulation ≤ 10 mm. This analysis included 191 patients. PGA formulations presented good correlations (≥ 0.65), but Bland-Altman plots showed clinically significant differences, which were statistically confirmed by comparison of means. Just over a half (51.8%) of patients scored all PGA formulations within a 20-mm interval. The proportion of those scoring ≤ 10 mm varied from 11.5 to 16.2%. When different formulations of PGA were used in each index, remission differences of up to 4.7, 4.7, 6.3, and 5.2% were observed. When formulations were used in their respective indices, as validated, the remission rates were similar (13.1, 13.6, 14.1, and 18.3%). Using PGA formulations interchangeably may have implications in the assessment of disease activity and in the attainment of remission, and this can impact upon management decisions.

Limited Health Literacy and Patient Confusion About Rheumatoid Arthritis Patient Global Assessments and Model Disease States

“…In addition, ratings on this instrument are frequently responsible for patients not achieving defined remission states. Remission is also often influenced by which of the many versions of the PGA‐VAS is presented to patients . Few data exist regarding RA patients’ perspective regarding this instrument, but the Outcome Measures in Rheumatology (OMERACT) group has published valuable qualitative information about patients’ attitudes regarding the PGA‐VAS instruments.…”

“…This potential confusion is concerning, given the prominent role the PGA‐VAS plays in RA clinical practice and research trials . Although the many different versions of the PGA‐VAS are often not scored similarly by RA patients, a low PGA score is mandated to reach either low disease activity or remission, as recommended in current disease management guidelines . In fact, numerous studies have shown that the PGA‐VAS score is often the sole reason that patients and research subjects do not meet criteria for remission, regardless of their literacy level .…”

Shared decision‐making in people with chronic disease: Integrating the biological, social and lived experiences is a key responsibility of nurses

“…Most patients are also unaware of the purpose of PGA, and have difficulties in completing the measurements reliably (Ferreira, de Wit, et al, 2019). With a quantitative study, we were able to confirm that the use of different versions of PGA introduces systematic errors in the rate of remission (Ferreira, Eugenio, et al, 2018).…”

Impact of Patient's Global Assessment on Achieving Remission in Patients With Rheumatoid Arthritis: A Multinational Study Using the METEOR Database

“…METEOR also incorporates data imported from other registries and the formulation of the PtGA question presented to patients is not exactly the same. Our previous research suggests that PtGA score varies by different formulations of the question. There was a significant amount of missing data (e.g., body mass index, smoking status, erosions) that could introduce some selection bias.…”

“…PtGA is highly affected by comorbidities and by other musculoskeletal and psychological conditions (e.g., osteoarthritis, fibromyalgia, depression) that cannot be improved by therapies targeting the inflammatory process, which makes it inappropriate to guide the readjustment of such therapies . Additionally, concerns have been raised regarding the variety of formulations used to ask this question , which have been shown to influence remission rates by 4.7% to 6.3% . The patient's health literacy also affects the validity and reliability of PtGA: approximately 40% of patients find the concept of PtGA confusing and the instruments difficult to mark .…”