Background Raynaud's phenomenon (RP) is frequently associated with the presence of scleroderma or other connective tissue diseases. To identify the presence of secondary RP is important to perform an adequate therapeutic management and to achieve the early control of these patients. Nailfold capillaroscopy is a safe, inexpensive and easy to perform method and has proven to be useful in identifying patients with secondary RP.
Objectives To assess the usefulness of nailfold capillaroscopy to discern between primary RP and secondary RP. We propose a predictive model to identify patients with secondary RP.
Methods Descriptive observational study involving 192 patients with primary and secondary RP. Capillaroscopy examination was performed to each of the patients in the HUP La Fe between January 2012 and January 2014. The rheumatologists responsible for carrying out the nailfold capillaroscopy were unaware of the clinical diagnosis of each patient. A predefined capillaroscopic pattern was assigned to each patient based on the findings of the capillaroscopic examination. Patients were classified on the basis of their clinical diagnosis in two groups (primary RP and secondary RP).
Results We studied 192 patients (169 women/20 men), with a mean age of 48.6±16.4 years (range 15-85).
The main pathologies observed were: Primary RP (n=124), Scleroderma/ Systemic sclerosis (32), Systemic Lupus Erythematosus (15), Rheumatoid arthritis (7), Sjögren's syndrome (7), Polymyositis/ Dermatomyositis (1) and others (6). The main capillaroscopic patterns observed were: Normal (49), Unspecific (77), Scleroderma pattern (34) and suggestive of other patterns of rheumatic diseases (32).
The following capillaroscopic parameters were observed significantly more often in the group of patients with RP secondary compared to those with primary RP: Presence of megacapillaries (47.1% vs 16.1%; p<0.01), presence of capillary tortuosity (82.4% vs 64.5%; p<0.01) and the presence of a decreased capillary density (25% vs 4.8%; p<0.01). The presence of capillary bleeding was also observed more frequently in patients with sencundary RP although this finding was not significant (64.7% vs 56.5%; p=0.32). Increased risk of secondary RP was observed in those patients in whom the nailfold capillaroscopy showed megacapillaries, capillary tortuosity and a decreased number of capillaries/mm.
The predictive model performed on the basis of the previously mentioned capillaroscopic parameters showed a good calibration and a corrected index of Harrell (index equivalent to the area under the ROC curve) of 0.71.
Conclusions The nailfold capillaroscopy can be useful to distinguish between primary RP and secondary RP. The presence of megacapillaries, an increased capillary tortuosity and a decreased number of capillaries/mm are the capillaroscopic parameters associated in our model to a greater risk for secondary RP. The use of a predictive model of secondary RP performed on the basis of these parameters can be useful for the detection of cases of secondary RP.
Disclosure of Interest None declared