Objectives: A previous study found that time to diagnosis was significantly longer from onset of Raynaud's phenomenon for women compared to men with diffuse systemic sclerosis (SSc) and that, in limited SSc, it was more than twice as long for women than men. That study was limited, however, by the small number of men in disease subtype subgroups. The objective of the present study was to investigate the association of sex with time to diagnosis of SSc using a substantially larger patient sample.
Methods: Association between sex and time to diagnosis was assessed overall and stratified based on diffuse versus limited disease using Kaplan-Meier curves and Cox proportional hazards models.
Results: There were 1,129 patients in the study (median age=56.0 years; 978 [86.6%] women). Time to diagnosis was significantly longer for women (median=1.1 years) than men (median 0.8= years; p=0.037) with diffuse SSc following onset of Raynaud's phenomenon. There were no significant or substantive sex differences in time to diagnosis after Raynaud's onset in limited SSc or from onset of first non-Raynaud's disease manifestation in diffuse or limited SSc.
Conclusions: Time to diagnosis was significantly longer for women compared to men with diffuse SSc following onset of Raynaud's phenomenon, but the difference was small and unlikely to be clinically significant. There were no differences in time to diagnosis following Raynaud's onset in limited disease or following onset of first non-Raynaud's disease manifestation in diffuse or limited disease. Overall, sex does not appear to influence time to diagnosis meaningfully.