Maxime Verhoeven

197 Development and validation of DAS-OST Conclusion Using the HandScan, RA disease activity (states) can be accurately estimated if OST- scores are combined with ESR, VAS and gender into a disease activity index (DAS-OST), which results in a quick and more objective disease activity index compared to joint count based disease activity indices. REFERENCES 1. Smolen, J. S. et al. EULAR recommendations for the management of rheumatoid arthritis with synthetic and biological disease-modifying antirheumatic drugs: 2016 update. Ann. Rheum. Dis. 76 , 960–977 (2017). 2. Smolen, J. S., Aletaha, D. & McInnes, I. B. Rheumatoid arthritis. Lancet 388 , 2023–2038 (2016). 3. Jacobs, J. W. G., ten Cate, D. F. & van Laar, J. M. Monitoring of rheumatoid arthritis disease activity in individual patients: still a hurdle when implementing the treat-to-target principle in daily clinical practice. Rheumatology 54 , 959–961 (2015). 4. Scott, D. L. & Houssien, D. A. Joint assessment in rheumatoid arthritis. Br. J. Rheumatol. 35 , 14–18 (1996). 5. Grunke, M. et al. Standardization of joint examination technique leads to a significant decrease in variability among different examiners. J. Rheumatol. 37 , 860–864 (2010). 6. Besselink, N. J. et al. Optical spectral transmission to assess inflammation in hand and wrist joints of rheumatoid arthritis patients. Rheumatology 57 , 865–872 (2018). 7. Besselink, N. J. et al. Novel optical spectral transmission (OST)-guided versus conventionally disease activity-guided treatment: study protocol of a randomized clinical trial on guidance of a treat-to-target strategy for early rheumatoid arthritis. Trials 20 , 226 (2019). 8. van Onna, M. et al. Assessment of disease activity in patients with rheumatoid arthritis using optical spectral transmission measurements, a non-invasive imaging technique. Ann. Rheum. Dis. 75 , 511–518 (2016). 9. Aletaha, D. et al. 2010 Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Arthritis Rheum. 62 , 2569–2581 (2010). 10. Balsa, A. et al. Value of disease activity score 28 (DAS28) and DAS28-3 compared to American College of Rheumatology-defined remission in rheumatoid arthritis. J. Rheumatol. 31 , 40–46 (2004). 11. Koo, T. K. & Li, M. Y. A guideline of selecting and reporting intraclass correlation coefficients for reliability research. J. Chiropr. Med. 15 , 155–163 (2016). 12. de Vet, H. C. W., Terwee, C. B., Mokkink, L. B. & Knol, D. L. Measurement in Medicine . (Cambridge University Press, 2011). 13. van Riel, P. L. C. M. The development of the disease activity score (DAS) and the disease activity score using 28 joint counts (DAS28). Clin. Exp. Rheumatol. 32 , S65–S74 (2014). 14. Triantafyllias, K., Heller, C., de Blasi, M., Galle, P. & Schwarting, A. Diagnostic value of optical spectral transmission in rheumatoid arthritis: associations with clinical characteristics and comparison with joint ultrasonography. J. Rheumatol. 47 , 1314–1322 (2020). 10