THU0357 NAILFOLD CAPILLARY MICROSCOPY HAS LIMITED PROGNOSTIC VALUE IN PREDICTING FUTURE DEVELOPMENT OF CONNECTIVE TISSUE DISEASE IN CHILDREN WITH RAYNAUD’S PHENOMENON.

Abstract

Background:For adults with Raynaud’s phenomenon (RP), nailfold capillary microscopy (NCM) is established to be an effective method for differentiating between PRP and SRP (1,2). Although Raynaud’s phenomenon (RP) is very common in childhood, studies on diagnostic methods to differentiate between primary RP (PRP) and secondary RP (SRP) at a young age are scarce (3,4).Objectives:The general aim of this study was to determine the prognostic value of nailfold capillary microscopy (NCM) in addition to antinuclear antibodies (ANAs) for later development of connective tissue diseases (CTD) in children with RP.Methods:This was a case-control study, in which 83 patients diagnosed with RP and having undergone NCM in childhood were retrospectively included. Based on whether they were diagnosed with a connective tissue disease (CTD) during follow-up, they were classified as PRP or SRP. PRP and SRP patients were compared on demographics, NCM and ANA positivity. Variables associated with SRP were included in a multivariate logistic regression model. Predictive values were calculated for NCM, ANA positivity and the combination of NCM and ANA positivity.Results:At the time of the baseline NCM, the mean age of the RP patients was 15.4±2.3 years. Averagely 6.4±3.2 years after the baseline NCM, 65 of the 83 patients were classified as PRP and 18 as SRP. The most common CTDs were MCTD and undifferentiated CTD. ANA positivity was associated with SRP (p<0.001). Of the NCM parameters, only capillary loss was associated with SRP (p=0.01). Abnormal numbers of dilated capillaries, giant capillaries and haemorrhages were not significantly associated with SRP. In a multivariate logistic regression model, only ANA positivity was predictive for SRP (OR 11.19, CI 3.07-40.79). ANA alone had a sensitivity of 66.7% and a specificity of 85.9% for SRP. ANA combined with capillary loss had a sensitivity of 33.3% and a specificity of 96.8%.Conclusion:This study demonstrates that childhood RP is primary in most cases. Whereas RP in adulthood is most strongly associated with SSc, children with RP seem to be at risk of developing other CTDs with less apparent NCM abnormalities. Dilated capillaries, giant capillaries and haemorrhages on NCM are not associated with the spectrum of CTDs that children are at risk for, and do not differentiate between primary and secondary RP. Although capillary loss on NCM is associated with SRP, capillary loss may add little to the predictive value of serology. To clarify which NCM parameters are helpful for early detection of SSc-like CTDs, additional research is required.