Background Lupus outcomes including mortality have been found to be worse in most ethnic minorities, including African Americans, Asians, and Hispanics, but little is known about North American Indigenous people (NAI).
Objectives To compare mortality in NAI SLE patients to Caucasian SLE patients followed at a single centre.
Methods Patients from a single academic center were followed from 1990-2013 using a custom database. Variables included date of birth, diagnosis, year of disease onset, ethnicity, clinic visits dates, and vital status if known. Records of all patients with a diagnosis of SLE (≥4 American College of Rheumatology criteria) were abstracted. For patients who had not been seen in the last 2 years, updated vital status was obtained from the hospital medical records department. Ethnicity was by self-report, and categorized into NAI, Caucasian and other. The age at diagnosis, disease duration and age at last follow up or age at death was calculated and compared between ethnic groups. Survival time was compared between NAI and Caucasians using Kaplan Meier and Cox proportional hazard models.
Results A total of 807 patients with SLE were identified: 201 (25%) patients were NAI, 501 (62%) were Caucasian, and the remaining 105 (13%) were of other ethnic backgrounds and were excluded from subsequent analyses. NAI patients were younger at diagnosis (NAI =32±15 years vs. Caucasian =37±15 years; p=0.001) and had a shorter disease duration at last follow up compared to Caucasians: (NAI =11±9 years vs. Caucasian =15±11 years; p=0.001.) More NAI had died by the end of the follow-up period (NAN =25% vs. Caucasian =18% p<0.001) and mean age at death was much younger in NAI (NAI =50±16 years vs. Caucasian =63±16 yrs p=0.001). Survival rates were significantly worse in NAI compared to Caucasians: 5 year survival was 92% vs. 97%; 10 year survival 85% vs. 92%; 15year survival 78% vs. 88% respectively (p<0.001). In a cox proportional hazards model, the risk of death overall was higher for the NAI (hazard ratio 3.3; 95%CI: 2.3-4.8) than for Caucasians, as was the risk of death following diagnosis (hazard ratio 2.1; 95%CI: 1.4-3.1).
Conclusions While mortality in our Caucasian lupus patients was comparable to recent reports in other regions, mortality was high in NAI patients, beginning within five years of diagnosis and continuing to increase over time, even though NAI patients were younger at diagnosis. While further research to identify the determinants of this excess mortality is ongoing, this study demonstrates the urgent need for improved care delivery for NAI with SLE to decrease the significant morbidity and mortality burden from this disease.
Disclosure of Interest : None declared
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