Risk factors for progression of carotid intima-media thickness in patients with systemic lupus erythematosus: protocol for an observational cohort study in China

Introduction: Accelerated atherosclerosis is a major complication of systemic lupus erythematosus (SLE), and it leads to increased cardiovascular morbidity and mortality in patients with SLE. This study aimed to investigate the natural progression of carotid intima-media thickness (CIMT), and to examine the risk factors for progression of CIMT and atherosclerotic plaques based on a Chinese SLE cohort.

Methods and analysis: Participants were continuously enrolled as outpatients of the Department of Rheumatology in Peking Union Medical College Hospital (PUMCH) from October 2013 to December 2016. Inclusion criteria were as follows: (1) age ≥18 years, (2) fulfilment of clinical classification criteria of SLE and (3) provision of signed written informed consent. Patients with clinically overt coronary artery disease, a history of cardiovascular disease (previous stroke, heart failure, myocardial infarction, angina or symptomatic peripheral artery disease) and malignancy, and pregnant/lactating women were excluded. The primary outcome is progression of CIMT from baseline. A total of 440 patients with SLE will be enrolled. Participants will receive follow-up surveys ~5 years after their baseline visit. A standard structural survey form, including demographic data, medical history, clinical and laboratory assessments and CIMT measurement, is planned for data collection at baseline and follow-up. The risk prediction model for progression of CIMT will be created by using a mixed effect model.

Ethics and dissemination: The study protocol was approved by the institutional review board of PUMCH (S-599). Informed consent was obtained from all participants according to the Declaration of Helsinki on Biomedical Research Involving Human Studies. All data will be managed confidentially according to guidelines and legislation. Dissemination will include publication of scientific papers and/or presentations of the study findings at international conferences.