OBJECTIVE: To identify features of systemic lupus erythematosus (SLE) associated with poor functional outcome as measured by the 36-item Medical Outcomes Study Short Form 36 Health Survey (SF-36). METHODS: Two hundred twenty-four patients with early SLE (70 Hispanic, 83 African American, and 71 white) enrolled in a longitudinal study of outcomes were evaluated at study entry. The 8 composite scales and 2 summary measures (physical and mental) of the SF-36 were the dependent variables. Independent variables--1) sociodemographic, 2) clinical features, 3) immunologic, 4) global scores, and 5) behavioral/cultural--were examined for each of the scales and summary measures and for each ethnic group. Significant variables in these analyses were then used to construct models to determine their association with each of the scales and the 2 summary measures for the entire population and the 3 ethnic groups. RESULTS: Self-reported physical and mental functioning were most consistently associated with abnormal illness-related behaviors, helplessness, fatigue, and pain at study entry. Helplessness was more strongly associated with functioning in the Hispanics than in the African American or white patients. Pain was strongly associated with physical but not mental health. The models were quite robust, accounting for 41% to 68% of the variance for the two summary measures. CONCLUSION: Patients' attitudes toward their disease, fatigue, and pain have greater impact on self-perceived functional levels, as measured by the SF-36, than do more objective measures of disease activity and damage such as the presence of specific autoantibodies and/or the occurrence of specific organ involvement. Interventions designed to improve outcome may need to include ethnic-specific as well as general strategies.