Limitations in study design hamper interpretation of studies evaluating the prognostic value of nailfold capillaroscopy in systemic sclerosis: a systematic literature review

Background: Nailfold capillaroscopy (NC) is a valuable diagnostic tool in systemic sclerosis (SSc). Increasing attention has focused on the prognostic potential of NC in predicting disease outcomes in SSc. Confirmation of the prognostic value of NC could facilitate earlier intervention and improve outcomes in SSc. We report a systematic literature review evaluating the prognostic value of NC in predicting disease outcomes in SSc.Methods: The review was conducted according to PRISMA guidelines (PROSPERO 2017: CRD42017071719). Standardised searches of EMBASE and MEDLINE (through July 2017) were undertaken to identify longitudinal studies examining the prognostic potential of NC in SSc. Non-English, non-original research, animal studies, non-adult studies and non-full length reports were excluded. The QUality In Prognosis Studies (QUIPS) tool was used to evaluate the risk of bias across six domains (Table 1). Study selection, data extraction and risk-of-bias assessment were undertaken independently by two reviewers and consensus reached where necessary.