Socio-economic status and the utilisation of physicians' services: results from the Canadian National Population Health Survey

Abstract

This paper assesses the extent to which Canada's universal health care system has eliminated socio-economic barriers in the use of physician services by examining the role of socio-economic status in the differential use of specific, publicly-insured, primary and specialist care services. Data from the 1994 National Population Health Survey, a nationally representative survey, were analysed using multiple logistic regression. In order to control for the association between primary and specialist utilisation, a two-staged least squares method was used for models explaining specialist utilisation. Health need, as measured by perceived health status and number of health problems, was found to be consistently associated with increased physician utilisation, for both primary and specialist visits. Whereas the likelihood of an individual making at least one visit to a primary care physician was found to be independent of income, those with lower incomes were more likely to be frequent users of primary care, that is, make at least six visits to a primary care physician. Even after adjusting for the greater utilisation of primary care services by those in lower socio-economic groups, and, therefore, their higher exposure to the risk of referral, the utilisation of specialist visits was greater for those in higher socio-economic groups. Canadians lacking a regular medical doctor were less likely to receive primary and specialist care, even after adjustments for socio-economic variables such as income and education. Although financial barriers may not directly impede access to health care services in Canada, differential use of physician services with respect to socio-economic status persists. After adjusting for differences in health need, Canadians with lower incomes and fewer years of schooling visit specialists at a lower rate than those with moderate or high incomes and higher levels of education attained despite the existence of universal health care.

Introduction

The implementation of a universal, publicly-funded medical insurance program in Canada was justified on the grounds that all citizens should have access to health-care services on the basis of need rather than ability to pay (Beck, 1973, Enterline et al., 1973, Manga et al., 1987). One of its primary goals was to provide all Canadian residents with necessary medical care on a prepaid basis, thereby reducing health inequalities and financial uncertainty. (Stewart, 1990). An important characteristic related to inequalities in health is socio-economic status (SES). The link between SES and health status has long been recognised, with lower income associated with poorer health status (Broyles et al., 1983, Manga et al., 1984, Mustard and Frohlich, 1995, Katz et al., 1996, McIsaac et al., 1997) Not only is this relationship positive, it also has no threshold; that is, the differentials do not merely affect the poor in relation to the wealthy but extend throughout all social classes (Pope, 1988).

Since the implementation of hospital insurance in 1958 and medical insurance in 1968, Canada's national health insurance system has done much to overcome the financial barriers to health service utilisation (Shah, 1994). One major study found that the implementation of universal health care resulted in a shift in the use of physician services from persons in higher income groups to persons in lower income groups (Enterline et al., 1973). Despite this shift in utilisation, barriers to the use of health care by the poor persist (Beck, 1973, Piperno, 1990, Haynes, 1991, McIsaac et al., 1997).

Most studies that considered a broad range of socio-demographic, economic and need characteristics, when examining the use of physician services, did not distinguish primary and specialist utilisation (Broyles et al., 1983, Manga et al., 1984). McIsaac et al. examined the utilisation of general practitioner (GP) and specialty services separately using the Ontario Health Survey (OHS) but there has been no nationally-representative study conducted that assessed these patterns for the 1990s. Moreover, McIsaac et al. did not control for the endogeneity of the use of GPs in accounting for specialist visits.

While insured residents may self-refer for primary care services, specialty and non-primary health services usually require referral from a GP (Kohn and White, 1976, Hulka and Wheat, 1985). Many of these services, including those provided by surgeons, allergists, rheumatologists, gynaecologists and psychiatrists, may be necessary to restore function or to enhance health status. Utilisation of referred services is comprised of two components. First, the patient initiates self-referral to a primary care provider and, second, referral to subsequent specialty care often depends on a visit to a primary care practitioner. By separating health utilisation into actions initiated by the patient and actions that require a general practitioner referral, greater understanding of the role of SES on health care utilisation may be gained.

The primary objective of this study is to explain, in a nationally representative sample, the role of SES in the differential use of publicly-insured, primary and specialty services in order to assess the extent to which socio-economic barriers in the use of physician services exist in Canada's universal health care system.