The effect of vitamin D3 and thyroid hormones on the capillaroscopy-confirmed microangiopathy in pediatric patients with a suspicion of systemic connective tissue disease-a single-center experience with Raynaud phenomenon

Raynaud phenomenon (RP) may be the first manifestation of a systemic connective tissue disease (SCTD). Early detection of dysfunction of small vessels called microangiopathy is essential for the diagnostic process. The focus of this single-center, retrospective study was to investigate the potential dependencies between microvascular image and laboratory markers measured in children with RP. The study analyzed the nail-fold video-capillaroscopy (NVC) findings and laboratory results of 81 children between the ages 6 and 17 who were referred to pediatric rheumatologist with a suspicion of SCTD. Out of 52 patients presenting with RP at the time of evaluation, abnormalities in capillary microscopic imaging were found in 34. NVC findings were then compared to levels of specific biomarkers in serum. Vitamin D3 serum levels have been significantly decreased in patients with RP (23.4 ng/mL ± 8.76 vs. 30.0 ng/mL ± 12.66, P = 0.0148). There were positive significant correlations between levels of vitamin D3 and acute-phase reactants in serum, such as C-reactive protein (P = 0.0292). Furthermore, free thyroxine levels (fT4) in patients with both RP (P = 0.0126) and micro-angiopathy (P = 0.05496) persisted in the lower range of the normal limit (< 1.0 ng/dL). Regular oral supplementation of vitamin D3 should be always considered in children with RP if deficiency is found. Additionally, low fT4 level (< 1.0 ng/dL) should be considered as an indication to perform NVC in patients suspected of SCTD even when they do not present RP.