Development and Validation of Rheumatoid Arthritis Disease Activity Indices Including HandScan (Optical Spectral Transmission) Scores

Abstract

Objective To develop and validate a composite rheumatoid arthritis (RA) disease activity index using optical spectral transmission (OST) scores obtained with the HandScan, replacing tender and swollen joint counts. Methods RA patients from a single center routinely undergoing HandScan measurements with at least 1 concurrent OST score and Disease Activity Score in 28 joints (DAS28) were included. Data were extracted from medical records. Linear regression analyses with the DAS28 as the outcome were performed to create a disease activity index (DAS‐OST). OST score, erythrocyte sedimentation rate (ESR), and patient global assessment (PtGA) visual analog scale (VAS), sex, age, disease duration, and rheumatoid factor status were evaluated as independent variables. Final models were derived based on the statistical significance of coefficients and model fit. Of the data, two‐thirds were used for development and one‐third for validation; external validation was performed in a cohort from another center. Agreement between DAS‐OST and DAS28 was assessed using the Bland‐Altman plot method and intraclass correlation coefficient (ICC). Diagnostic value of the DAS‐OST was determined for established definitions of remission, low disease activity (LDA), and high disease activity (HDA). Results Data of 3,358 observations from 1,505 unique RA patients were extracted. DAS‐OST was defined as: –0.44 + OST × 0.03 + male × –0.11 + LN(ESR) × 0.77 + PtGA VAS × 0.03. The ICCs between DAS‐OST and DAS28 were 0.88 (95% confidence interval [95% CI] 0.87–0.90) and 0.82 (95% CI 0.75–0.86) and measurement errors were 0.58 and 0.87 in internal and external validation, respectively. Sensitivity for remission, LDA, and HDA was 79%, 91%, and 43%, respectively, and specificity was 92%, 80%, and 96% in external validation. Conclusion Using the HandScan, RA disease activity can be accurately estimated if combined with ESR, PtGA VAS, and sex into a disease activity index (DAS‐OST).

Optical imaging (HandScan) can identify ultrasound remission in rheumatoid arthritis

“…total HS score), which corresponds to the average score per joint multiplied by 22, ranging from 0 to 66. At the patient level, we also calculated DAS-OST score and DAS-OST without PtGA score according to Verhoeven et al [ 8 ] (DAS OST : -0.44 + OST*0.03 + male*-0.11 + LN (ESR) * 0.77 + PtGA * 0.03 ; DAS-OST without PtGA : -0.11 + OST*0.04 + male*-0.25 + LN (ESR) * 0.88). For total HS score, the clinical remission threshold proposed by Besselink et al is a total HS score ≤ 11 with no more than one joint with unitary OST score > 1 [ 24 ].…”

“…For total HS score, the clinical remission threshold proposed by Besselink et al is a total HS score ≤ 11 with no more than one joint with unitary OST score > 1 [ 24 ]. For the DAS-OST and DAS-OST without PtGA, the clinical remission threshold was ≤ 2.6 [ 8 ].…”

“…A longitudinal association between the total HS score and the disease activity score (DAS) of 28 joints (DAS28) has been found, but the explained variance is quite low [ 6 ]. In 2022, Verhoeven et al developed composite index scores based on OST: DAS-OST, and DAS-OST without patient global assessment (PtGA) on a visual analogue scale (VAS) (PtGA-VAS) [ 8 ]. They concluded that the DAS-OST score seems to be the most accurate to monitor the patient’s disease activity, with good negative and positive predictive values for clinical remission.…”

Monitoring of rheumatoid arthritis: a patient survey on disease insight and possible added value of an innovative inflammation monitoring device

“…This may help to understand the current activity of a patient's arthritis as well as to localize inflammatory activity. Previous research showed that the HandScan is a sensitive and specific test with good validity [15,16]. This makes it interesting to examine the HandScan as a potential addition to or (partial) replacement of current measures for inflammatory activity such as blood tests, DAS28, MRI, and ultrasound…”

“…A device based on optical spectral transmission-the HandScan-has recently been developed for detecting inflammation [15]. Optical spectral transmission technology might be a valuable addition to or (partial) replacement of current measures for inflammatory activity such as the DAS28, blood tests, MRI and ultrasound [16]: it is an objective measure and the test can be performed by anyone after a short training. For more information on the HandScan, see Fig.…”