Patrick Donio1, Wesley Fidler2, Juan Pablo Diaz-Martinez3, Elvira Bangert4, Zareen Ahmad5, Medha Soowamber6 and Sindhu Johnson7, 1Thunder Bay Regional Health Sciences Centre, Northern Ontario School of Medicine University, Queen's University, Thunder Bay, ON, Canada, 2Northern Ontario School of Medicine, Thunder Bay, ON, Canada, 3Toronto Western Hospital, Toronto, ON, Canada, 4Toronto Scleroderma Program, Mount Sinai Hospital, University of Toronto, Toronto, ON, Canada, 5Toronto Scleroderma Program, Mount Sinai Hospital, Toronto Western Hospital, University of Toronto, Toronto, ON, Canada, 6Toronto Scleroderma Program, Mount Sinai Hospital, Toronto Western Hospital, University of Toronto, Woodbridge, ON, Canada, 7Institute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, ON, Canada
Background/Purpose: Systemic sclerosis (SSc) is a multisystem fibrosing autoimmune disease with a high mortality rate. Ethnicity can influence prevalence and disease characteristics in SSc. Less is known about SSc-associated interstitial lung disease (SSc-ILD), an important subgroup with even higher mortality rate. We investigate whether there are ethnic variations in people with SSc-ILD.
Methods: We conducted a retrospective cohort study of the Toronto Scleroderma Program – a network of academic and community clinics (1970-2023). Ethnicity was self-reported and categorized as Caucasian, Black, East-Asian, South Asian, or First Nations. We evaluated differences in demographics, disease manifestations, comorbidities, and survival in people with SSc-ILD. Kaplan-Meier survival curves were used to determine median survival and survival at 1-5, 10, 15, and 20 years. A Cox proportional hazards model estimated survival, adjusting for age, age of diagnosis, disease duration, and comorbidities.
Results: 405 people with SSc-ILD were included with n=234 (58%) Caucasian, n=57 (14%) South-Asian, n=49 (12%) East-Asian, n=28 (7%) Black, n=16 (4%) First Nation and n=22 (5%) Other. The median age at SSc diagnosis was significantly younger for First Nations ethnicity compared to Caucasian (38.4 years versus 52.0 years, p< 0.01). More Caucasians, South-Asians, and East-Asians had limited disease (53.2%, 51.8%, 53.1%), while more Black and First Nation had diffuse disease (57.1%, 62.5% respectively). Esophageal dysmotility was more common in Black and First Nations (96.4%, 93.8% respectively) than Caucasians, South Asians, and East Asians (88.5%, 80.7%, 71.4% respectively, p=0.01). Coronary artery disease occurred more frequently in First Nations (18.8%) than Caucasians, South Asians and East Asians (11.5%, 3.5%, 6.1%, p=0.04). East Asians had significantly better 10-year survival 93.2% (95%CI 85%, 100%) than Caucasians 78.3% (95%CI 72.1%, 85.1%). People of First Nations ethnicity appeared to have worse 10-year survival of 65.9% (95%CI 42.9%, 100%) but this was not statistically significant. In the adjusted survival analysis, age at diagnosis (p< 0.001) was an independent risk factor mortality, whereas ethnicity was not associated with mortality.
Conclusion: Ethnic variations in demographics, disease manifestations and comorbidities exist in SSc-ILD yet this does not result in significant differences in survival across ethnicities.
P. Donio: None; W. Fidler: None; J. Diaz-Martinez: None; E. Bangert: None; Z. Ahmad: None; M. Soowamber: None; S. Johnson: None.