Validity and reliability of the EULAR instrument RAID.7 as a tool to assess individual domains of impact of disease in rheumatoid arthritis: a cross-sectional study of 671 patients

Abstract

Objective: The rheumatoid arthritis impact of disease (RAID) questionnaire comprises seven patient-important domains of disease impact (pain, function, fatigue, sleep disturbance, emotional well-being, physical well-being, coping). RAID was validated as a pooled-weighted score. Its seven individual items separately could provide a valuable tool in clinical practice to guide interventions targeting the patient's experience of the disease. The aim was to separately assess the psychometric properties of each of the seven numeric rating scale (NRS) of the RAID (RAID.7).

Material and methods: Post hoc analyses of data from the cross-sectional RAID study and from the Rainbow study, an open-label 12-week trial of etanercept in patients with RA. Construct validity of each NRS was assessed cross-sectionally in the RAID data set by Spearman's correlation with the respective external instrument of reference. Using the rainbow data set, we assessed reliability through intraclass correlation coefficient between the screening and the baseline visits and responsiveness (sensitivity to change) by standardised response mean between baseline and 12 weeks.

Results: A total of 671 patients with RA with features of established disease were analysed, 563 and 108 from RAID and Rainbow, respectively. The NRS correlated moderately to strongly with the respective external instrument of reference (r=0.62-0.81). Reliability ranged from 0.64 (0.51-0.74) (pain) to 0.83 (0.76-0.88) (sleep disturbance) and responsiveness from 0.93 (0.73-1.13) (sleep disturbance) to 1.34 (1.01-1.64) (pain).

Conclusion: The separate use of the individual NRS of RAID (RAID.7) is valid, feasible, reliable and sensitive to change, representing an opportunity to improve the assessment and treatment of disease impact with minimal questionnaire burden.

Trial registration number: NCT00768053.

Keywords: arthritis; health care; outcome assessment; patient reported outcome measures; rheumatoid.

Figure 1

Comparison of mean values obtained in each RAID domain between patients in the RAID study (n=563) with different levels of disease activity status (DAS28(3 v)-ESR). *Correspond to p<0.05 by Kruskal-Wallis test, bars correspond to mean, lines to 95% CI, obtained through bootstrapping method. DAS28(3 v)-ESR, Disease Activity Score-3 variables-erythrocyte sedimentation rate; RAID, Rheumatoid Arthritis Impact of Disease.

Figure 2

Mean NRS for each RAID domain, according to disease activity status (Das28(3v)-ESR) at week 12 in rainbow study (n=97) * correspond to p<0.05, independent samples t-test, bars correspond to mean, lines to 95% CI, obtained through bootstrapping method. DAS28(3 v)-ESR: Disease activity Score, 3 variables with erythrocyte sedimentation rate; LDA: Low Disease Activity; NRS: Numerical Rating Scale; RAID, Rheumatoid Arthritis Impact of Disease.

Figure 3

Comparison of change in RAID domains (baseline to week 12 between responders and non-responders (DAS28(3 v)-ESR) to bDMARD, in the Rainbow trial (n=97). *Correspond to p<0.05, independent samples T-test, bars correspond to mean, lines to 95% CI obtained through bootstrapping method. bDMARD, biological Disease Modifying Anti-Rheumatic Drugs; DAS28(3 v)-ESR: Disease Activity Score, 3 variables with erythrocyte sedimentation rate; RAID, Rheumatoid Arthritis Impac of Disease.