3-Variable Score Better Represents Disease Activity in Patients With RA and Concomitant Fibromyalgia

A measurement of evaluating disease activity in patients with rheumatoid arthritis (RA) and concomitant fibromyalgia, called the DAS28 V3 score, was more beneficial for the clinical assessment of disease activity than traditional methods, according to data presented at the European Congress of Rheumatology (EULAR) 2023.¹

The disease activity score (DAS) was originally developed using a large prospective study of patients with early RA who were frequently evaluated using disease activity measures.²

The 28 joint disease activity score (DAS28), a modification of the original DAS, measures 28 joints, most of which are in the hands, as well as the knees, shoulders, and elbows. Improvements are measured by the reduction in score, in which a .6 reduction is indicative of a moderate improvement and a ≥1.2 reduction represents a major improvement in disease activity. This simplified version is commonly used in clinical trials and as a treatment decision tool.

“Several studies have shown that rheumatoid arthritis patients with concomitant fibromyalgia can cause an overestimation of the disease activity assessed by the DAS28 by inflating the patient reported components,” wrote a group of investigators from Hôpital Mongi Slim, Rheumatology Department, in Marsa, Tunisia.

To mitigate this potential issue, DAS28 V3, a further simplified version, is calculated based on only 3 variables: swollen joint counts, tender joint counts, and C-reactive protein (CRP). Another version, the DAS28 V4 also includes a patient global assessment, although previous research using the Danish registry for biological treatment in rheumatology (DANBIO) indicated that the DAS28 V3 score was only slightly underestimated compared with the DAS28 V4 version.³

The cross-sectional, observational study included patients with RA both with and without concomitant fibromyalgia. RA diagnosis was confirmed using American College of Rheumatology (ACR)/European Alliance of Associations for Rheumatology (EULAR) 2010 criteria, while fibromyalgia was confirmed using 2016 ACR criteria. Demographics and disease characteristics were collected, and all patients received a clinic-biological and ultrasound evaluation of RA activity. The ultrasound assessment included an evaluation of synovial/tenosynovial hypertrophy in both grey scale and in Power Doppler (PD).

In total, 80 patients were included, with 40 patients placed in the RA cohort and 40 patients placed in the RA and concomitant fibromyalgia cohort. Characteristics of RA and epidemiological data were comparable among both groups. The subjective activity parameters were higher in the patients with RA and fibromyalgia cohort.

No significant differences were observed between both groups regarding mean DAS28, DAS28 V3, clinical disease activity index (CDAI), and simple disease activity index (SDAI) (P = .12, P = .14, P = .5, and P = .2, respectively). However, the DAS28 was significantly greater than DAS28 V3 in those with concomitant fibromyalgia (P = .000). No difference was observed between DAS28 and DAS28 V3 in patients with RA without a fibromyalgia diagnosis.

Multivariate analysis in the concomitant fibromyalgia cohort revealed DAS28 V3 was significantly positively associated with the presence of synovial hypertrophy (r = .494, P = .001) and PD synovitis (r = .155, P = .032). Conversely, patient global assessment (PGA) reported a significant negative association (r = -.392, P = .049 and r = -0.642, P = .005 respectively).

References

1. ^{S Miladi, B A Hiba, F Alia, S Ben Yaacoub, et al. DAS28 With Three Variables Performance in a Cohort of Rheumatoid Arthritis Patients With and Without Concomitant Fibromyalgia. Paper presented at: European Congress of Rheumatology (EULAR) 2023. Milan, Italy. May 31 – June 3, 2023.}
2. ^{van Riel PL, Renskers L. The Disease Activity Score (DAS) and the Disease Activity Score using 28 joint counts (DAS28) in the management of rheumatoid arthritis. Clin Exp Rheumatol. 2016;34(5 Suppl 101):S40-S44.}
3. ^{Madsen OR. Is DAS28-CRP with three and four variables interchangeable in individual patients selected for biological treatment in daily clinical practice?. Clin Rheumatol. 2011;30(12):1577-1582. doi:10.1007/s10067-011-1847-6}