Chinese SLE Treatment and Research Group (CSTAR) registry:VIII. Influence of socioeconomic and geographical variables on disease phenotype and activity in Chinese patients with SLE

AIM The aim of this study was to estimate the influence of socioeconomic and geographical variables on disease phenotype and activity of systemic lupus erythematosus (SLE) in a Chinese population. METHODS Data on 904 therapy-naive SLE patients from the Chinese SLE Treatment and Research Group (CSTAR), which is a nation-wide database of SLE patients, were used to evaluate the influence of socioeconomic status (SES) and geographical regions on disease phenotypes. The influence of regional climate and economic variables (i.e., data from the database of the Chinese Statistical Yearly Annals) on disease activity and nephropathy was further analyzed in a multivariate analysis to identify some of the environmental factors contributing to SLE. RESULTS Phenotype differences in SLE were found between patients with different SES. In the multivariate regression analysis that considered regional economic and climate factors, after adjusting for age, gender and disease duration, lower educational levels (β: -0.122, P = 0.001), lower availability of medical technical personnel (MTP) per 1000 people (β: -0.192, P < 0.001), higher annual duration of sunshine (β: 0.178, P = 0.010) and residence in southern China (β: 0.165, P = 0.001) were significantly associated with higher disease activity scores. Living in southern China (odds ratio [OR]: 1.907, P = 0.002) seemed to be a significant risk factor for nephropathy. A high number of MTP per 1000 people (OR: 0.951, P = 0.014) and relatively high temperatures were determined to be protective factors for nephropathy (OR: 0.946, P = 0.011). CONCLUSIONS The phenotype pattern and disease activity varied between SLE patients by SES and other regional variables, such as educational level, availability of medical technical personnel, annual sunshine duration and regional temperature.