Does socioeconomic status affect outcomes in early inflammatory arthritis? Data from a canadian multisite suspected rheumatoid arthritis inception cohort.
OBJECTIVE
To assess the effect of socioeconomic status (SES) on outcomes in patients with early inflammatory arthritis, using data from the Canadian Early Arthritis Cohort (CATCH) study.


METHODS
In an incident cohort, 2023 patients were recruited, and allocated to low SES or high SES groups based on education and income. Outcomes at baseline and 12 months were analyzed in relation to SES including the 28-joint Disease Activity Score (DAS28), Simplified Disease Activity Index (SDAI), pain, patient's global assessment scale (PtGA), the Health Assessment Questionnaire-Disability Index (HAQ-DI), and the SF12-v2 Health Survey, using the ANOVA, chi-squared test, and regression analyses.


RESULTS
The CATCH population had 43% with high school education or less and 37% in the low-income group (< 50,000 Can$ per annum household income). The low-education group had higher DAS28 at baseline (p = 0.045), becoming nonsignificant at 12 months and lower physical component score on SF12-v2 at baseline (p = 0.022). Patients in the low-income group presented with higher HAQ-DI (p = 0.017), pain (p = 0.035), PtGA (p = 0.004), and SDAI (p = 0.022). Low-income versus high-income groups were associated with an OR above the median for HAQ-DI (1.20; 95% CI 1.00-1.45), PtGA (1.27; 95% CI 1.06-1.53), and SDAI (1.25; 95% CI 1.02-1.52) at baseline. The association with low income persisted at 12 months for HAQ-DI (OR 1.30; 95% CI 1.02-1.67), but not for other variables.


CONCLUSIONS
Low SES was initially associated with higher disease activity, pain, and PtGA, and poorer function. At 1 year, outcomes were similar to those with high SES, with the exception of HAQ-DI.
From the Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, London, Ontario, Canada; Rheumatology, Hospital for Special Surgery, Cornell University, New York, New York, USA; Rheumatology Division, Université de Sherbrooke, Sherbrooke, Quebec; Arthritis Centre, University of Manitoba, Winnipeg, Manitoba; Southlake Regional Health Centre, Newmarket, Ontario; Rheumatic Disease Unit, Institut de Rhumatologie, Montreal, Quebec; Rheumatology, Mount Sinai Hospital, University of Toronto, Toronto; Rheumatology, St. Joseph's Health Care, London, Ontario, Canada.G. Yang, MD, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario; V.P. Bykerk, MD, FRCPC, Rheumatology, Hospital for Special Surgery, Cornell University; G. Boire, MD, FRCPC, Rheumatology Division, Universite de Sherbrooke; C.A. Hitchon, MD, FRCPC, Arthritis Centre, University of Manitoba; J.C. Thorne, MD, FRCPC; D. Tin, BSc Pharm, Southlake Regional Health Centre; B. Haraoui, MD, FRCPC, Rheumatic Disease Unit, Institut de Rhumatologie; E.C. Keystone, MD, FRCPC, Rheumatology, Mount Sinai Hospital, University of Toronto; J.E. Pope, MD, FRCPC, MPH, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, and Rheumatology, St. Joseph's Health Care.
Grace
G
Yang
From the Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, London, Ontario, Canada; Rheumatology, Hospital for Special Surgery, Cornell University, New York, New York, USA; Rheumatology Division, Université de Sherbrooke, Sherbrooke, Quebec; Arthritis Centre, University of Manitoba, Winnipeg, Manitoba; Southlake Regional Health Centre, Newmarket, Ontario; Rheumatic Disease Unit, Institut de Rhumatologie, Montreal, Quebec; Rheumatology, Mount Sinai Hospital, University of Toronto, Toronto; Rheumatology, St. Joseph's Health Care, London, Ontario, Canada.G. Yang, MD, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario; V.P. Bykerk, MD, FRCPC, Rheumatology, Hospital for Special Surgery, Cornell University; G. Boire, MD, FRCPC, Rheumatology Division, Universite de Sherbrooke; C.A. Hitchon, MD, FRCPC, Arthritis Centre, University of Manitoba; J.C. Thorne, MD, FRCPC; D. Tin, BSc Pharm, Southlake Regional Health Centre; B. Haraoui, MD, FRCPC, Rheumatic Disease Unit, Institut de Rhumatologie; E.C. Keystone, MD, FRCPC, Rheumatology, Mount Sinai Hospital, University of Toronto; J.E. Pope, MD, FRCPC, MPH, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, and Rheumatology, St. Joseph's Health Care.
Vivian P
VP
Bykerk
From the Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, London, Ontario, Canada; Rheumatology, Hospital for Special Surgery, Cornell University, New York, New York, USA; Rheumatology Division, Université de Sherbrooke, Sherbrooke, Quebec; Arthritis Centre, University of Manitoba, Winnipeg, Manitoba; Southlake Regional Health Centre, Newmarket, Ontario; Rheumatic Disease Unit, Institut de Rhumatologie, Montreal, Quebec; Rheumatology, Mount Sinai Hospital, University of Toronto, Toronto; Rheumatology, St. Joseph's Health Care, London, Ontario, Canada.G. Yang, MD, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario; V.P. Bykerk, MD, FRCPC, Rheumatology, Hospital for Special Surgery, Cornell University; G. Boire, MD, FRCPC, Rheumatology Division, Universite de Sherbrooke; C.A. Hitchon, MD, FRCPC, Arthritis Centre, University of Manitoba; J.C. Thorne, MD, FRCPC; D. Tin, BSc Pharm, Southlake Regional Health Centre; B. Haraoui, MD, FRCPC, Rheumatic Disease Unit, Institut de Rhumatologie; E.C. Keystone, MD, FRCPC, Rheumatology, Mount Sinai Hospital, University of Toronto; J.E. Pope, MD, FRCPC, MPH, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, and Rheumatology, St. Joseph's Health Care.
Gilles
G
Boire
From the Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, London, Ontario, Canada; Rheumatology, Hospital for Special Surgery, Cornell University, New York, New York, USA; Rheumatology Division, Université de Sherbrooke, Sherbrooke, Quebec; Arthritis Centre, University of Manitoba, Winnipeg, Manitoba; Southlake Regional Health Centre, Newmarket, Ontario; Rheumatic Disease Unit, Institut de Rhumatologie, Montreal, Quebec; Rheumatology, Mount Sinai Hospital, University of Toronto, Toronto; Rheumatology, St. Joseph's Health Care, London, Ontario, Canada.G. Yang, MD, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario; V.P. Bykerk, MD, FRCPC, Rheumatology, Hospital for Special Surgery, Cornell University; G. Boire, MD, FRCPC, Rheumatology Division, Universite de Sherbrooke; C.A. Hitchon, MD, FRCPC, Arthritis Centre, University of Manitoba; J.C. Thorne, MD, FRCPC; D. Tin, BSc Pharm, Southlake Regional Health Centre; B. Haraoui, MD, FRCPC, Rheumatic Disease Unit, Institut de Rhumatologie; E.C. Keystone, MD, FRCPC, Rheumatology, Mount Sinai Hospital, University of Toronto; J.E. Pope, MD, FRCPC, MPH, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, and Rheumatology, St. Joseph's Health Care.
Carol A
CA
Hitchon
From the Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, London, Ontario, Canada; Rheumatology, Hospital for Special Surgery, Cornell University, New York, New York, USA; Rheumatology Division, Université de Sherbrooke, Sherbrooke, Quebec; Arthritis Centre, University of Manitoba, Winnipeg, Manitoba; Southlake Regional Health Centre, Newmarket, Ontario; Rheumatic Disease Unit, Institut de Rhumatologie, Montreal, Quebec; Rheumatology, Mount Sinai Hospital, University of Toronto, Toronto; Rheumatology, St. Joseph's Health Care, London, Ontario, Canada.G. Yang, MD, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario; V.P. Bykerk, MD, FRCPC, Rheumatology, Hospital for Special Surgery, Cornell University; G. Boire, MD, FRCPC, Rheumatology Division, Universite de Sherbrooke; C.A. Hitchon, MD, FRCPC, Arthritis Centre, University of Manitoba; J.C. Thorne, MD, FRCPC; D. Tin, BSc Pharm, Southlake Regional Health Centre; B. Haraoui, MD, FRCPC, Rheumatic Disease Unit, Institut de Rhumatologie; E.C. Keystone, MD, FRCPC, Rheumatology, Mount Sinai Hospital, University of Toronto; J.E. Pope, MD, FRCPC, MPH, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, and Rheumatology, St. Joseph's Health Care.
J Carter
JC
Thorne
From the Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, London, Ontario, Canada; Rheumatology, Hospital for Special Surgery, Cornell University, New York, New York, USA; Rheumatology Division, Université de Sherbrooke, Sherbrooke, Quebec; Arthritis Centre, University of Manitoba, Winnipeg, Manitoba; Southlake Regional Health Centre, Newmarket, Ontario; Rheumatic Disease Unit, Institut de Rhumatologie, Montreal, Quebec; Rheumatology, Mount Sinai Hospital, University of Toronto, Toronto; Rheumatology, St. Joseph's Health Care, London, Ontario, Canada.G. Yang, MD, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario; V.P. Bykerk, MD, FRCPC, Rheumatology, Hospital for Special Surgery, Cornell University; G. Boire, MD, FRCPC, Rheumatology Division, Universite de Sherbrooke; C.A. Hitchon, MD, FRCPC, Arthritis Centre, University of Manitoba; J.C. Thorne, MD, FRCPC; D. Tin, BSc Pharm, Southlake Regional Health Centre; B. Haraoui, MD, FRCPC, Rheumatic Disease Unit, Institut de Rhumatologie; E.C. Keystone, MD, FRCPC, Rheumatology, Mount Sinai Hospital, University of Toronto; J.E. Pope, MD, FRCPC, MPH, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, and Rheumatology, St. Joseph's Health Care.
Diane
D
Tin
From the Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, London, Ontario, Canada; Rheumatology, Hospital for Special Surgery, Cornell University, New York, New York, USA; Rheumatology Division, Université de Sherbrooke, Sherbrooke, Quebec; Arthritis Centre, University of Manitoba, Winnipeg, Manitoba; Southlake Regional Health Centre, Newmarket, Ontario; Rheumatic Disease Unit, Institut de Rhumatologie, Montreal, Quebec; Rheumatology, Mount Sinai Hospital, University of Toronto, Toronto; Rheumatology, St. Joseph's Health Care, London, Ontario, Canada.G. Yang, MD, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario; V.P. Bykerk, MD, FRCPC, Rheumatology, Hospital for Special Surgery, Cornell University; G. Boire, MD, FRCPC, Rheumatology Division, Universite de Sherbrooke; C.A. Hitchon, MD, FRCPC, Arthritis Centre, University of Manitoba; J.C. Thorne, MD, FRCPC; D. Tin, BSc Pharm, Southlake Regional Health Centre; B. Haraoui, MD, FRCPC, Rheumatic Disease Unit, Institut de Rhumatologie; E.C. Keystone, MD, FRCPC, Rheumatology, Mount Sinai Hospital, University of Toronto; J.E. Pope, MD, FRCPC, MPH, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, and Rheumatology, St. Joseph's Health Care.
Boulos
B
Haraoui
From the Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, London, Ontario, Canada; Rheumatology, Hospital for Special Surgery, Cornell University, New York, New York, USA; Rheumatology Division, Université de Sherbrooke, Sherbrooke, Quebec; Arthritis Centre, University of Manitoba, Winnipeg, Manitoba; Southlake Regional Health Centre, Newmarket, Ontario; Rheumatic Disease Unit, Institut de Rhumatologie, Montreal, Quebec; Rheumatology, Mount Sinai Hospital, University of Toronto, Toronto; Rheumatology, St. Joseph's Health Care, London, Ontario, Canada.G. Yang, MD, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario; V.P. Bykerk, MD, FRCPC, Rheumatology, Hospital for Special Surgery, Cornell University; G. Boire, MD, FRCPC, Rheumatology Division, Universite de Sherbrooke; C.A. Hitchon, MD, FRCPC, Arthritis Centre, University of Manitoba; J.C. Thorne, MD, FRCPC; D. Tin, BSc Pharm, Southlake Regional Health Centre; B. Haraoui, MD, FRCPC, Rheumatic Disease Unit, Institut de Rhumatologie; E.C. Keystone, MD, FRCPC, Rheumatology, Mount Sinai Hospital, University of Toronto; J.E. Pope, MD, FRCPC, MPH, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, and Rheumatology, St. Joseph's Health Care.
Edward C
EC
Keystone
From the Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, London, Ontario, Canada; Rheumatology, Hospital for Special Surgery, Cornell University, New York, New York, USA; Rheumatology Division, Université de Sherbrooke, Sherbrooke, Quebec; Arthritis Centre, University of Manitoba, Winnipeg, Manitoba; Southlake Regional Health Centre, Newmarket, Ontario; Rheumatic Disease Unit, Institut de Rhumatologie, Montreal, Quebec; Rheumatology, Mount Sinai Hospital, University of Toronto, Toronto; Rheumatology, St. Joseph's Health Care, London, Ontario, Canada.G. Yang, MD, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario; V.P. Bykerk, MD, FRCPC, Rheumatology, Hospital for Special Surgery, Cornell University; G. Boire, MD, FRCPC, Rheumatology Division, Universite de Sherbrooke; C.A. Hitchon, MD, FRCPC, Arthritis Centre, University of Manitoba; J.C. Thorne, MD, FRCPC; D. Tin, BSc Pharm, Southlake Regional Health Centre; B. Haraoui, MD, FRCPC, Rheumatic Disease Unit, Institut de Rhumatologie; E.C. Keystone, MD, FRCPC, Rheumatology, Mount Sinai Hospital, University of Toronto; J.E. Pope, MD, FRCPC, MPH, Schulich School of Medicine and Dentistry, Department of Internal Medicine, University of Western Ontario, and Rheumatology, St. Joseph's Health Care. janet.pope@sjhc.london.on.ca.
Janet E
JE
Pope
D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000188:drug therapy*; D002170:Canada; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D012074:Remission Induction; D012923:Social Class; D012959:Socioeconomic Factors
D018501:Antirheumatic Agents
EARLY RHEUMATOID ARTHRITIS; EDUCATION; INCIDENT COHORT; INCOME; REMISSION; SOCIOECONOMIC STATUS