Re-evaluation of nailfold capillaroscopy in discriminating primary from secondary Raynaud’s phenomenon and in predicting systemic sclerosis: a randomised observational prospective cohort study

ABSTRACT

Background

Primary Raynaud’s phenomenon (pRP) is difficult to distinguish from secondary (sRP). Although nailfold capillaroscopy (NFC) may detect early alterations, no universal criteria yet discriminate between pRP from sRP.

Objectives

To create and validate two NFC scores that could distinguish pRP from sRP and that could predict systemic sclerosis (SSc), respectively.

Methods

We performed NFC on two separate cohorts with isolated RP, and recorded number of capillaries per field, enlarged/giant capillaries, crossed/bizarre patterns, microhemorrhages, neoangiogenesis, rarefaction, edema, blood flow velocity, stasis. By multivariate regression analysis, we evaluated the adjusted prognostic role of these features in a derivation cohort of 656 patients. Results were used to construct algorithm-based prognostic scores (A and B). These scores were then tested on a confirmation cohort of 219 patients.

Results

Score A was unable to discriminate sRP from pRP (low negative predictive values with high positive predictive values for any cut-point); score B was unable to discriminate progression to SSc or a SSc-spectrum disorder (low positive predictive values with high negative predictive values for lower cut-points).

Conclusion

NFC patterns, believed as specific, showed low discriminatory power and on their own are unable to reliably discriminate sRP from pRP or predict evolution to SSc.

KEYWORDS:

• Nailfold capillaroscopy
• primary Raynaud’s phenomenon
• secondary Raynaud’s phenomenon
• systemic sclerosis
• videocapillaroscopy
• raynaud’s disease
• connective tissue disease

Article highlights

• Distinction between primary and secondary Raynaud’s phenomenon can be challenging;

• Nailfold capillaroscopy lacks discriminatory power between pRP and sRP;

• In early stages nailfold capillaroscopy is unable to predict who will develop systemic sclerosis;

• We must start looking at NFC in a different way, thinking how we can improve or complement it.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Author contributions

M Amaral, P Ames and J Delgado Alves contributed to the study conception and design. Material preparation, data collection and analysis were performed by M Amaral, F Seguro Paula, J Caetano and J Delgado Alves. The first draft of the manuscript was written by M Amaral and all authors commented on previous versions of the manuscript and on revision. All authors read and approved the final manuscript.

All authors take full responsibility for the integrity and accuracy of all aspects of the work.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Ethics Statement

The ethics committee of our hospital approved the research protocol (2004/CEHFF, revised in 2018: 15/2018). Informed consent was obtained from all individual participants (or their legally authorized representative) included in the study, which was carried out according the Declaration of Helsinki.

Additional information

Funding

This paper was not funded.