Background Routine monitoring of Rheumatoid arthritis (RA), i.e. by using DAS28 (1), requires considerable resources in rheumatology outpatient departments. Further, a new awareness has been raised of including the patient perspective in disease monitoring in daily clinical practice (2).
The Flare instrument (FI) is a newly developed self-administrated tool to identify flares between consultations. It is developed in France, and is the result of 99 semi-structured interviews together with statements from 13 rheumatologists, generated through a Delphi process (3).
Objectives To translate the FI into Danish and to investigate the validity and reliability of this FI version among a consecutive sample of RA patients visiting a large Danish outpatient clinic.
Methods Forward and back-ward translation was carried out according to the guidelines by Guillemin et al.(4).
Both reliability and validity was evaluated among RA patients treated with conventional DMARDs. In the reliability test, a 10-day period between test and re-test was used to reduce the risk of recall bias and new flaresAbsolute measurement errors were estimated by calculating the standard error of the measurement (SEM) and minimally detectable change (MDC). The intra class correlation coefficients (ICC), with corresponding 95% CI, were used to assess reliability.
Criterion validity was evaluated using DAS28 as the gold standard. A cut off value of ≤3.2 was sat to discriminate between low and high disease activity in DAS28, and of ≤2.5 in the FI. A 2x2 table was used to calculate the sensitivity, specificity and positive and negative predictive values (PPV and NPV).
Results The reliability test showed the following results: SEM: 0.44 (95% CI: 0.37; 0.55),nd ICC: 0.97 (95% CI: 0.95; 0.99). The minimal detectable change was 1.23. The results of the criterion validity test was: Sensitivity: 86% (95% CI: 71-95), spececificity: 52% (95% CI: 39-66), PPV: 59% (95% CI: 46-71) and NPV: 81% (95% CI: 66-99).
Conclusions The FI presents excellent reliability. Further the criterion validity shows that the instrument identifies RA patients without flare in >80% of the cases. Potentially, this opens up for new ways of RA disease monitoring in the future.
Prevoo ML, van 't Hof MA, Kuper HH, van Leeuwen MA, van de Putte LB, van Riel PL. Modified disease activity scores that include twenty-eight-joint counts. Development and validation in a prospective longitudinal study of patients with rheumatoid arthritis. Arthritis Rheum 1995 Jan;38(1):44-48.
Kirwan JR, Hewlett SE, Heiberg T, Hughes RA, Carr M, Hehir M, et al. Incorporating the patient perspective into outcome assessment in rheumatoid arthritis–progress at OMERACT 7. J Rheumatol 2005 Nov;32(11):2250-2256.
Berthelot JM, De Bandt M, Morel J, Benatig F, Constantin A, Gaudin P, et al. A tool to identify recent or present rheumatoid arthritis flare from both patient and physician perspectives: The 'FLARE' instrument. Ann Rheum Dis 2012 Jul;71(7):1110-1116.
Guillemin F, Bombardier C, Beaton D. Cross-cultural adaptation of health-related quality of life measures: literature review and proposed guidelines. J Clin Epidemiol 1993 Dec;46(12):1417-1432.
Disclosure of Interest None declared
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