Evaluation of: Kaiser R, Cleveland CM, Criswell LA: Risk and protective factors for thrombosis in systemic lupus erythematosus: results from a large multi-ethnic cohort.Ann. Rheum. Dis.68, 238–241 (2009). In this study Kaiser et al. examined the risk factors for the occurrence of thrombotic events in systemic lupus erythematosus patients for the University of California, San Francisco (CA, USA) genetics project. Smoking and disease severity (history of nephritis and immunomodulatory use) were found to be risk factors for the occurrence of thrombotic events whereas hydroxychloroquine use was found to be protective.