Geographical variation of disease manifestations in systemic sclerosis: a report from the EULAR Scleroderma Trials and Research (EUSTAR) group database

Background: Systemic sclerosis (SSc) is a vasculopathy with increased tissue deposition of collagen. The aetiology is unknown. Genetic and environmental susceptibility factors have been implicated. It is unknown whether disease presentation varies within Europe. Aims and Methods: The baseline data of all SSc patients entered in the EULAR Scleroderma Trials and Research (EUSTAR) database up to April 2007 were analysed for geographical differences with regard to organ involvement, and geographical clusters with regard to clinical subsets (diffuse vs limited SSc) and autoantibodies (anticentromere vs anti-Scl70). Results: 3661 patients from 79 centres in 62 cities and 23 countries were analysed. There was no clear trend between geographical coordinates and SSc subsets, although there appeared to be an increased prevalence of Scl70 in the more eastern centres. There was no association between geographical longitude or latitude and the age at the onset of Raynaud's phenomenon or the onset of non-Raynaud's symptoms. There was also a trend for the more eastern centres to care for patients with a higher prevalence of more severe organ manifestations (pulmonary arterial hypertension, cardiac involvement). Between different centres within one city there was a large variability in the frequency of organ complications. Conclusion: This analysis suggests that eastern centres care for more severe SSc manifestations in Europe. Large differences in patient referral account for a large local variability of SSc presentations and preclude the identification of genetic or environmental factors.