Diagnostic Value of Capillary Density at Periungual Capillaroscopy in the Diagnosis of Connective Tissue Disease

Abstract

Our study aims to demonstrate the contribution of quantitative analysis of capillaroscopic study in the early diagnosis of connective tissue diseases. One hundred and fifteen patients were evaluated by capillaroscopy. Raynaud's phenomenon is the most frequently encountered acro-syndrome leading to the request for capillaroscopic examination. capillaroscopy reveals minor dystrophy in 83.5% of patients and major dystrophy in 60% of them. On a quantitative level, 77 patients present, among the four examined fingers, at least one finger with a capillary density <25 capillaries/3mm. For the diagnosis of connective tissue disease, this threshold is statistically significant with an odds ratio of 4.21 (95% CI = 1.47-11.99; p = 0.008). For this same diagnosis, its positive predictive value is 38%, its negative predictive value is 86%. A low capillary density, as a diagnostic test for connective tissue disease, has a sensitivity of 85% and a specificity of 41%. There is no significant difference between the decrease in capillary density for the diagnosis of connective tissue disease for each examined finger in terms of positive predictive value, negative predictive value, sensitivity, and specificity