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Time in Remission Proposed as New Outcome Measure for RA
Time in remission showed validity as a predictor of remission among patients with rheumatoid arthritis (RA), according to research published in Rheumatology.
The authors observed, “Achieving targeted disease activity (DA) is the primary therapeutic strategy in RA. Point measurements of DA are done at out-patient visits, however true DA between visits remains unobserved.” They set out to determine the validity of a new outcome measure, time in remission (TIR), to estimate unobserved disease activity between scheduled appointments and to predict remission.
Participants were enrolled in the Czech ATTRA-RA registry. The researchers calculated TIR “using linear interpolation of the Disease Activity Score-28 for Rheumatoid Arthritis with Erythrocyte Sedimentation Rate (DAS28-ESR) determined at outpatient visits,” they explained. “Correlation coefficients were computed between TIR and DAS28-CRP, Health Assessment Questionnaire (HAQ), Simple Disease Activity Index (SDAI), patient global assessment (PGA), and physician global assessment (PhGA).”
TIR was used as a predictor of remission (SDAI ≤3.3) and nondisability (HAQ <0.5) through logistic regression. The predictive value of TIR was compared with point and sustained remission using the cross-validated area under receiver-operating curves.
Among the 2618 RA patients who initiated anti-TNF therapy in 2010 and were followed until 2020 or until treatment discontinuation, 56% had no remission (TIR = 0) during the first 6 months; 22% of patients reached sustained remission (TIR = 1), while 22% of patients had point remissions with 0 < TIR < 1.
“EULAR good responders and moderate/nonresponders spent 64 ± 42% and 6 ± 18% of time in remission, respectively. The mean TIR grew during the follow-up and was correlated with DAS28-CRP, SDAI, HAQ, PGA, and PhGA (P < 0.0001),” the investigators wrote. “TIR at 3 and 6 months predicted remission (SDAI ≤3.3) and nondisability (HAQ <0.5) at 13 and 19 months better than point or sustained remission.”
The authors concluded, “TIR is an intuitive way of estimating unobserved DA between scheduled visits; its calculation only requires two consecutive DA values (https://www.medevio.cz/tir-calculator/). TIR is a valid predictor of RA outcomes.”
—Rebecca Mashaw
Reference:
Tužil J, Mlčoch T, Závada J, Svoboda M, Pavelka K, Doležal T. Time in remission as an alternative outcome measure for rheumatoid arthritis: a 10-year prospective study of 2618 new users of anti-TNF. Rheumatology. 2022;61(6): 2295–2306
