Marie Lan ¹ Feben W. Alemu ¹ Shehzad Ali ^1,2,3,4*

• ¹ Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
• ² Schulich Interfaculty Program in Public Health, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
• ³ Department of Health Sciences, Faculty of Sciences, University of York, Heslington, Yorkshire and the Humber, United Kingdom
• ⁴ WHO Collaborating Centre for Knowledge Translation and Health Technology Assessment in Health Equity, Ottawa, Canada

The Canada Health Act mandates universal access to medical services for all Canadians. Despite this, there are significant disparities in access based on socioeconomic status, race and ethnicity, immigrant status, and indigeneity. However, there is limited evidence on specialist services use among older adults in Canada. The primary objective of this study is to identify the associations of social determinants of health with difficulty in utilizingaccess toing needed medical specialist services for Canadians aged 45 years and older. The second objective is to identify the reasons for having difficultynot being able to accessing the this needed specialist care.A cross-sectional analysis of the Canadian Longitudinal Study of Aging survey data was conducted to examine the associations of social determinants of health with difficulty utilizingaccessing to specialist services. Experiencing difficulty accessing specialist care is defined as not seeing a specialist when needed in the last 12 months. Based on Andersen's model of health services use, a multivariable logistic regression model was used to evaluate the associations between 'difficulty utilizingnot being able to accessing the needed specialist service(s) in the last 12 months' and individual-level sociodemographic determinants.Approximately 97% of those who required specialist care in the last year were able to visit a specialist. Of the participants who were not able to did not access the needed reported difficulty utilizing specialist services, about half (50.90%) did not see a specialist because they were still waiting for a visit. Being younger (45-54 years), living in a rural area, having some post-secondary education, having a household income below $50,000 a year, not having a family physician, and having fair or poor perceived general health were associated with greater difficulty. Residents of British Columbia and Nova Scotia had a higher likelihood of reporting difficulty compared to those residing in Ontario.While a majority of respondents were able to access specialist services when needed, those who had difficulty in access were more likely to come from socially marginalized groups. Targeted policy interventions and improved health system coordination can reduce these barriers to care.