Rheumatoid arthritis in a north american native population: longitudinal followup and comparison with a white population.
OBJECTIVE
To describe differences in phenotype and outcomes in North American Native (NAN) patients with rheumatoid arthritis (RA) followed prospectively and compared to white patients with RA.


METHODS
Patients from a single academic center were followed over 20 years using a custom database. Data included diagnoses, year of disease onset, ethnicity, modified Health Assessment Questionnaire (mHAQ) score, patient and physician global scores, tender and swollen joint counts, treatment, serology, and erythrocyte sedimentation rate (ESR). Records of all white (n = 1315) and NAN (n = 481) patients with RA were abstracted. Cumulative treatment data and clinical measures were compared.


RESULTS
Disease duration was longer in white patients compared to NAN patients (16 +/- 11 vs 14 +/- 10 years, respectively; p = 0.03). Onset age was 34 years for NAN patients and 43 years for white patients (p < 0.001). NAN patients were more frequently positive for rheumatoid factor (89% vs 74%; p < 0.001) and antinuclear antibody (57% vs 21%; p < 0.001). Although mean tender joint counts and swollen joint counts were similar, NAN patients had higher Lansbury scores (weighted joint count; 66.5 vs 49.7; p < 0.001), mHAQ scores (1.1 vs 0.9; p = 0.001), and ESR (31 vs 25 mm/h; p < 0.012). NAN patients had more frequent knee (53% vs 34%; p < 0.001) and elbow (62% vs 48%; p = 0.007) involvement. Compared to white patients, NAN patients took a higher lifetime number of disease-modifying antirheumatic drugs (3.2 +/- 1.9 vs 2.2 +/- 1.7; p < 0.001), had more combination therapy (38% vs 29%; p = 0.002), and had more frequent prednisone use (55% vs 39%; p < 0.001).


CONCLUSIONS
Compared to white patients, NAN patients with RA develop disease earlier, are more frequently seropositive, have greater large joint involvement, and greater disease burden, although treatment is more aggressive. These differences are present early and persist throughout the disease course.
Peschken
Christine A
CA
Department of Medicine, Immunology, and the Section of Rheumatology, University of Manitoba, Winnipeg, Manitoba, Canada. cpeschken@hsc.mb.ca
Hitchon
Carol A
CA
Robinson
David B
DB
Smolik
Irene
I
Barnabe
Cheryl R
CR
Prematilake
Suraj
S
El-Gabalawy
Hani S
HS
D000328:Adult; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000208:ethnology* / Q000503:physiopathology; D001799:Blood Sedimentation; D002170:Canada / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006304:Health Status; D006801:Humans; D007198:Indians, North American / Q000208:ethnology*; D007596:Joints / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D044465:White People / Q000208:ethnology*