Are the clinical phenotypes of systemic sclerosis determinant for osteoporosis and fragility fractures?

Systemic sclerosis (SSc) is associated with an increased risk of osteoporosis and fractures. The aim of this single-center cross-sectional study was to evaluate whether clinical phenotype and nailfold videocapillaroscopy (NVC) pattern could influence bone mineral density (BMD) values and fragility fractures in patients with SSc.

A cohort of 84 consecutive outpatients (age 63.7 ± 13.7 years) diagnosed with SSc, 43 classified as diffuse cutaneus SSc (dSSc) and 41 as limited cutaneus SSc (lSSc), were enrolled in the study. All patients underwent BMD by Dual Energy X-ray Absorptiometry (DX, pulmonary function tests for diffusing capacity of carbon monoxide (DLCO), and NVC to be assigned to an "early," "active," or "late" pattern.

Patients with dSSc exhibited significantly lower BMD values compared to those with lSSc; moreover, the prevalence of osteoporosis and major osteoporotic fractures were higher in dSSc than in lcSSc (39,6% and 41,9% vs. 29,2% and 34,1%, respectively). Patients with a "late" or "active" NVC pattern had a more marked reduction in BMD with respect to those with a "early" pattern (p < 0.05). Moreover, patients with dSSc showed a greater reduction in DLCO values compared to those with lSSc in all three capillaroscopic patterns (p < 0.05). DLCO reduction and history of previous fracture were independent predictors of total hip BMD in dSSc patients.

Patients with SSc, and particularly those with a "diffuse" phenotype, have a high prevalence of osteoporosis and major osteoporotic fractures. Furthermore, in both SSc phenotypes, the presence of an "active" or "late" capillaroscopic pattern was associated with reduced BMD and DLCO values.