The Patient Self-Administered Inflammatory Arthritis Detection Study

Early diagnosis and treat-to-target strategies improve outcomes for patients with inflammatory arthritis (IA). One approach for reducing diagnostic delay is using standardized patient-completed questionnaires to support referral decisions. This study evaluated the discriminatory referral performance of 2 validated questionnaires in newly referred rheumatology patients in British Columbia, Canada.

Patients completed the Early Inflammatory Arthritis Questionnaire (EIAQ) and Case Finding Axial Spondyloarthritis (CaFaSpA) questionnaire. Predictive scores for IA were calculated using existing algorithms and compared to the reference standard of their rheumatologist diagnosis. Discriminative performance was tested using the area under the receiver-operating characteristics curve (AUC), and diagnostic performance was tested using metrics, including sensitivity and specificity. Exploratory regression models were used to predict IA with different combinations of questionnaire questions.

Of 92 participants, 30 (33%) had time-sensitive IA (TS-IA), 35 (38%) other IA, and 27 (29%) non-IA. Time from referral to rheumatologist visits for patients with TS-IA was 44 days (IQR 28-83), 69 (IQR 40-102) for "other IA," 65 (IQR 34-99) for "non-IA," and was longer for women (+ 9 days) and in nonmetropolitan areas (+ 16 days). Only 7 patients had axial spondyloarthritis, precluding discriminative analysis of the CaFaSpA. The EIAQ had an AUC of 0.59 (95% CI 0.49-0.68), sensitivity of 33% (95% CI 19-51%), and specificity of 84% (95% CI 73-91); alternate algorithms based on EIAQ and CaFaSpA questions delivered AUCs up to 0.80 (95% CI 0.68-0.90).

The results support the utility and feasibility of routine collection of EIAQ and CaFaSpA questionnaires for discriminating patients with IA from those with non-IA.