Insight from convergent validity of assessment of systemic sclerosis–associated Raynaud phenomenon with nailfold capillaroscopy

Objectives
The assessment of systemic sclerosis–associated Raynaud phenomenon (ASRAP) questionnaire was recently developed. We tested the convergent validity of the ASRAP instrument with patient demographics and capillary morphology on nailfold capillaroscopy (NFC).

Methods
Participants completed the ASRAP (range 20–80; higher scores unfavourable) and underwent NFC using Dinolite™. We collected demographic and relevant clinical data. Two blinded assessors classified NFC images as ‘scleroderma pattern’ present or absent and recorded specific abnormalities. We assigned the NFC semi-quantitative score (range 0–3) based on the frequency of these abnormalities. Descriptive statistics were generated, and regression and correlation analyses were used to evaluate associations between ASRAP, NFC and clinical factors.

Results
Seventy-five patients [87% women, 78% white, 77% with limited cutaneous SSc] with a mean (SD) age of 58 (14) were recruited from scleroderma clinics. ASRAP scores were 11.2 points higher in women compared with men with other significant variables held constant. The NFC semi-quantitative score weakly correlated with ASRAP (Spearman’s σ = 0.23, P = 0.05), with moderate correlation in winter (Spearman’s σ = 0.36, P = 0.04). Holding other variables constant, patients with dilated capillaries and capillary dropout had higher ASRAP scores by 6.1 and 6.8 points, respectively.

Conclusion
In SSc patients, females reported higher ASRAP scores. Greater proportion of ‘scleroderma pattern’ NFC abnormalities as well as specific abnormalities like dilated capillaries and capillary dropout were associated with higher ASRAP providing mechanistic insight and supporting the construct validity of ASRAP for assessing SSc-RP.

Lay Summary
What does this mean for patients?
Raynaud phenomenon (RP) is a common and troublesome manifestation of SSc (scleroderma) that causes painful colour changes in the fingers and toes, especially with cold exposure or stress. The assessment of systemic sclerosis–associated Raynaud phenomenon (ASRAP) questionnaire was recently developed to capture how RP affects daily life from the patient’s perspective. In this study, we examined how ASRAP scores related to changes seen in the small blood vessels of the fingers using a simple microscope test called nailfold capillaroscopy. We found that people with more severe damage to the small blood vessels—especially those with dilated or missing capillaries—tended to report worse RP symptoms on the ASRAP. This relationship was even stronger during the cold weather months when symptoms are often worse. These findings support use of the ASRAP to measure the real-world impact of RP on patients with SSc. Using the ASRAP together with nailfold capillaroscopy may be a useful approach for assessing RP disease severity and evaluating whether treatments improve patients’ quality-of-life.