Nailfold videocapillaroscopy-defined capillaroscopic abnormality burden in systemic lupus erythematosus: a controlled cross-sectional study.

INTRODUCTION/

OBJECTIVES

Nailfold videocapillaroscopy (NVC) abnormalities are recognized in systemic lupus erythematosus (SLE), but their meaning remains uncertain. We examined whether standardized NVC quantifies structural capillaroscopic abnormality burden in SLE.

METHODS

In this single-centre cross-sectional study, 65 SLE patients and 46 non-autoimmune controls underwent standardized NVC. Six parameters were semi-quantitatively scored and combined into microangiopathy, morphological, and total scores. Between-group associations were assessed using adjusted negative binomial regression. Within-SLE correlation, treatment-adjusted, and exploratory cluster analyses were performed.

RESULTS

Total score was higher in SLE than controls (15 [10-21] vs. 2 [0-4], p < 0.001). After adjustment for age, sex, BMI, smoking, diabetes, and hypertension, SLE was associated with total (IRR 7.64, 95% CI 4.93-11.84), microangiopathy (IRR 9.48, 95% CI 5.94-15.14), and morphological scores (IRR 5.99, 95% CI 3.84-9.35; all p < 0.001). Density loss showed the largest component-level estimate (IRR 129.68, 95% CI 30.67-548.26) and was interpreted cautiously because of sparse controls. Microhaemorrhages were not associated with SLE (IRR 1.35, p = 0.452). Within SLE, only giant capillaries showed nominal correlations with disease duration (ρ = 0.298, p = 0.016) and neutrophils (ρ = 0.271, p = 0.029); serological signals were FDR-negative. Organ-level models were largely negative; musculoskeletal and discoid signals attenuated after treatment adjustment. Exploratory clustering identified low/high-burden groups (n = 52/13; silhouette 0.479), with limited high-burden stability.

CONCLUSIONS

Standardized NVC identified greater structural capillaroscopic abnormality burden in SLE, but not a surrogate for activity, serology, organ involvement, or treatment response. Prognostic or clinical utility requires prospective multicentre validation incorporating cumulative treatment exposure.