SP0131 RELIABILITY IN THE LAST 10 YEARS: CAPILLAROSCOPIC CHARACTERISTICS VERSUS INSTRUMENTAL DETECTION

Background: With nailfold capillaroscopy there are different aspects of reliability to consider, including reliability of qualitative image grading (e.g. ‘early”, ‘active” and ‘late”) and also of semi-quantitative and quantitative measures including capillary density, apical width and presence of giant capillaries. The reliability of image acquisition (i.e. test-retest reliability) is especially important if nailfold capillaroscopic parameters are to be used in longitudinal studies (e.g. clinical trials) which involve acquiring repeat images over time. Lastly when assessing reliability, it is important to recognise that the nailfold capillaries cannot always be clearly seen, and cannot therefore be evaluated. Objectives: To highlight the different aspects of reliability relating to nailfold capillaroscopy and how these have been addressed in studies over the last 10 years. Methods: Review of recent studies. Results: Intra–observer reliability has been shown in several studies to be higher than inter–observer. Assessment of ‘evaluability” varies between observers and therefore also needs to be taken into account when assessing reliability. Subject to evaluability, certain parameters demonstrate high intra– and inter–observer reliabilities. Reliability differs across different capillaroscopic parameters. Conclusion: Recent studies examining reliability of capillaroscopy suggest that certain parameters, including image grade, capillary density and apex width have high intra-and inter-observer reliabilities (subject to nailfold image evaluability, which remains a major challenge). Standardised training is likely to improve reliability. References: [1] Murray AK, Vail A, Moore TL, et al. The influence of measurement location on reliability of quantitative videocapillaroscopy in patients with SSc. Rheumatol 2012; 51 : 1323-30. [2] Overbury R, Murtaugh MA, Fisher A, et al. Primary care assessment of capillary abnormalities in patients with Raynaud”s phenomenon. Clin Rheumatol 2015; 34: 2135-40. [3] Smith V, Beeckman S, Herrick AL, et al. An EULAR study group pilot study on reliability of simple capillaroscopic definitions to describe capillary morphology in rheumatic diseases. Rheumatol 2016; 55: 883-90. [4] Dinsdale G, Moore T, O”Leary N, et al. Intra-and inter-observer reliability of nailfold videocapillaroscopy - A possible outcome measure for systemic sclerosis-related microangiopathy. Microvascular Research 2017; 112: 1-6. [5] Dinsdale G, Moore T, O”Leary N, et al. Quantitative outcome measures for systemic sclerosis-related microangiopathy – reliability of image acquisition in nailfold capillaroscopy. Microvascular Research 2017;113:56-9. [6] Boulon C, Devos S, Mangin M, et al. Reproducibility of capillaroscopic classifications of systemic sclerosis: results from the SCLEROCAP study. Rheumatology 2017; 56: 1713-20. [7] Cutolo M, Melsens K, Herrick AL, et al. Reliability of simple capillaroscopic definitions in describing capillary morphology in rheumatic diseases. Rheumatology (Letter) 2018; 57: 757-9. Disclosure of Interests: None declared