Systemic lupus erythematosus in North American Indians: a population based study.

OBJECTIVE

To evaluate the prevalence, disease course, and survival of patients with systemic lupus erythematosus (SLE) in a population of over 120,000 North American Indians (NAI), and contrast the results to those in the non-Indian population.

METHODS

The regional arthritis center database and the medical records of all rheumatologists, hematologists, nephrologists, and general internists with > 1 patient with SLE were searched for cases of SLE diagnosed between 1980 and 1996. A random survey of 20% of family physicians serving this population suggested that > 85% of all SLE cases were identified. Demographics, SLE Disease Activity Index (SLEDAI) scores, Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) damage scores. clinical manifestations, and therapy for NAI were contrasted with the results in Caucasians (CAUC).

RESULTS

We identified 257 cases meeting the ACR criteria for SLE diagnosed between 1980 and 1996. There were 49 NAI cases, resulting in a prevalence of 42.3/100,000, compared to a prevalence of 20.6/100,000 for the remainder of the population. NAI patients were younger at diagnosis, had higher SLEDAI scores at diagnosis, and had more frequent vasculitis, proteinuria and cellular casts. There were no treatment differences at diagnosis or at 2 years, but NAI patients were significantly more likely to receive treatment with prednisone or immunosuppressives at the last clinic visit. The NAI patients had similar damage scores at diagnosis, but significantly higher scores at 2 years and at the last clinic visit. NAI ethnicity increased the likelihood of death more than 4-fold.

CONCLUSION

The prevalence of SLE was increased 2-fold in the NAI population. NAI patients had higher SLEDAI scores at diagnosis and more frequent vasculitis and renal involvement, required more treatment later in the disease course, accumulated more damage following diagnosis, and had increased fatality.