The preliminary validation of laser Doppler flowmetry in systemic sclerosis in accordance with the OMERACT filter: A systematic review

Objectives: To investigate the validation status of laser Doppler flowmetry (LDF) in systemic sclerosis (SSc) according to the ‘Outcome Measures in Rheumatologic Clinical Trials’ (OMERACT) filter. Methods: The literature was systematically reviewed to identify all reports assessing the microcirculatory flow in SSc patients. The OMERACT filter –including the domains of truth, discrimination and feasibility– was applied and a quality assessment was done by the ‘Good Methods Checklist’. To ease the comparison between studies the results were grouped per dynamic test situation: basal, cold/heat challenge and occlusion. Results: The literature search resulted in 4332 hits. Based on title and abstract screening 243 hits were retained and of these, 52 full texts described an assessment by LDF in SSc patients. Finally, 18 studies passed the quality assessment and form the object of this review. The review reveals that expert consensus is lacking on the face and content validity of LDF in SSc. The construct validity of LDF, on the other hand is partially validated. Conflicting results exist on the discriminant capacity of LDF in distinguishing healthy from diseased patients, primary from secondary Raynaud's phenomenon and in differentiating between disease subsets. Yet, complementing an LDF-measurement with a heat challenge, as well as the evaluation of the post-occlusive hyperaemic response, has the potential to elicit a difference between healthy and diseased patients. Lastly, data on the feasibility of LDF in SSc is lacking in the identified literature. Conclusion: This systematic review emphasizes the very preliminary validation status of LDF in the assessment of the microcirculatory flow in SSc.