Associations between social determinants of health and long-term outcomes in systemic lupus erythematosus: a nationwide population-based cohort study in Sweden.

OBJECTIVES: To examine the association between social determinants of health (SDH) and outcomes in systemic lupus erythematosus (SLE), in a European setting. METHODS: We conducted a nationwide, register-based cohort study in Sweden including 2434 individuals aged 23-59 years with newly diagnosed SLE, 2005-2021. SDH were assessed at diagnosis and included education, income, marital status, work ability, unemployment and immigration status. Outcomes were organ damage (measured using the Lupus Register-Based Organ Damage Index) and all-cause mortality. Cox proportional hazards models estimated HRs, adjusting for age, sex and morbidity. Sensitivity analyses included SDH measured 2 years prior to diagnosis. RESULTS: During follow-up, a total of 1044 (42.4%) newly diagnosed patients with SLE developed organ damage and 140 (6%) died. There was an increased risk of organ damage associated with sick leave or disability (HR: 1.44; 95% CI 1.27 to 1.64), lower income (HR: 1.33; 95% CI 1.09 to 1.63), being divorced or widowed (HR: 1.30; 95% CI 1.10 to 1.54) at diagnosis. The same SDH were also associated with mortality, as was lower education level (HR: 1.67; 95% CI 1.05 to 2.66). Immigration status and unemployment did not associate with organ damage or mortality. Results were similar when examining SDH measured 2 years prior to diagnosis. CONCLUSIONS: In this population-based SLE cohort, lower education, lower income, being divorced, widowed or single and reduced work ability were independently associated with increased risk of organ damage and mortality. These findings support integrating SDH into risk stratification models and equity-focused interventions to improve SLE care and outcomes.