Nailfold capillaroscopy for the early diagnosis of the scleroderma spectrum of diseases in patients without Raynaud's phenomenon.

Background: The utility of nailfold capillaroscopy in the evaluation of patients without Raynaud's phenomenon is unclear.

Objective: This study aims to compare the utility of nailfold capillaroscopy for the early diagnosis of the scleroderma-spectrum of diseases in patients who present with Raynaud's phenomenon, undifferentiated non-Raynaud's phenomenon features and positive systemic sclerosis-associated antibodies without scleroderma-spectrum of disease features.

Methods: Eligible patients were divided into three referral criteria groups: (I) Raynaud's phenomenon; (II) Undifferentiated non-Raynaud's phenomenon features and (III) Positive systemic sclerosis-associated autoantibodies without features to suggest scleroderma-spectrum of diseases. This includes systemic sclerosis, mixed connective tissue disease and dermatomyositis. The association between baseline scleroderma pattern on nailfold capillaroscopy (systemic sclerosis-nailfold capillaroscopy) and final diagnosis at follow-up was determined using logistic regression analysis. Test characteristics of nailfold capillaroscopy were compared and stratified by referral groups.

Results: Of 95 patients followed-up for a mean of 1.6 years, 28 (29.5%) patients developed scleroderma-spectrum of diseases, 36 (37.9%) patients had suspected/other connective tissue disease and 27 (28.4%) patients had no connective tissue disease. Baseline systemic sclerosis-nailfold capillaroscopy was significantly associated with the development of scleroderma-spectrum of diseases in patients from Group I (odds ratio, 7.1, p = 0.01) and Group II (odds ratio 7.3, p = 0.005). In Group II patients, nailfold capillaroscopy had a sensitivity, specificity, positive and negative predictive values of 71.4%, 76.5%, 55.6% and 86.7%, respectively. Specificity (81.8%) and PPV (69.2%) were the highest in Group I patients. Nailfold capillaroscopy had the highest negative predictive value in Group III (100%), followed by Group II (86.7%) and Group I (78.3%) patients.

Conclusion: In addition to evaluating patients with Raynaud's phenomenon, nailfold capillaroscopy was useful in the evaluation and exclusion of scleroderma-spectrum of diseases in patients with undifferentiated non-Raynaud phenomenon features and those with systemic sclerosis-associated antibodies without features to suggest scleroderma-spectrum of diseases.