Background Patient involvement and personalisation of healthcare has become increasingly important in managing chronic diseases. Knowledge about their disease and its treatment is an important precondition for patients to be able to be involved in their own care.[1] Hence, EULAR recommends education to be an integral and continuous element of Rheumatoid Arthritis (RA) management, so that patient can be involved in their RA care.

An instrument to assess patients' knowledge about their disease and its treatment can provide insight into the effectiveness of healthcare professionals' education efforts. Moreover, it can be used as an instrument to personalize education based on individual patients' knowledge gaps. Currently available patient knowledge questionnaires were developed before the introduction of biologicals as well as treat to target strategies in rheumatoid arthritis (RA). Therefore we started the development and validation of an RA knowledge questionnaire for patients.

Objectives To propose an instrument to measure factual disease related knowledge in RA patients with additional focus on knowledge related to modern treatment methods.

Methods Content to be covered by the instrument was adopted from existing questionnaires. Consensus was reached on relevant content by a RAND modified Delphi scoring procedure by six rheumatology nurses and six rheumatologists, and a subsequent consensus meeting among six rheumatology nurses and four rheumatologists. Six rheumatology nurses and five rheumatologists provided written feedback on a preliminary pool of items written to assess the identified content domains. Subsequently, a focus group among nine patients was organised to identify additional content areas that might have been omitted from the item pool. Readability, feasibility and comprehensiveness of the resulting pool of 63 items were rated by eight patients from the focus group.

Results Cross-sectional data of 340 patients recruited from Bernhoven rheumatology department were used to evaluate psychometric properties. Preliminary analysis suggests that 21 (27%) items should be discarded based on an item total point biserial correlation <0.30. Confirmatory factor analysis with weighted least squares estimation on the polychoric correlation matrix suggested acceptable fit for a unidimensional measurement model for the remaining 45 items (CFI =0.95, TLI=0.95, RMSEA=0.02, WRMR=0.95). Internal consistency was also high for 45 items, with Cronbach's α=0.92.

Conclusions These preliminary results suggest that the questionnaire is a valid and reliable measure for assessing factual disease related knowledge in RA patients. Further validation efforts based on modern item response theory based approaches are ongoing as well as work directed at developing a calibrated item bank, tailored short-forms and a computerized adaptive testing algorithm.

1. Joseph-Williams N, Elwyn G, Edwards A. Knowledge is not power for patients: a systematic review and thematic synthesis of patient-reported barriers and facilitators to shared decision making. Patient education and counseling. 2014;94(3):291–309.

Acknowledgement We thank all rheumatology nurses, rheumatologists and patients who have helped in the development or validation of the questionnaire.

Disclosure of Interest M. de Jonge Grant/research support from: Dutch Arthritis Foundation (Reumafonds), M. Oude Voshaar: None declared, A. Huis: None declared, M. van de Laar: None declared, M. Hulscher: None declared, P. van Riel: None declared