Equity is defined as the fair and just distribution of resources. In Canada this means equal access (or equal service) for equal need . Health care systems that limit access or fail to provide equitable access to care for populations have been said to accentuate social disparities in health . Arguably, the real test of equity of access involves determining whether there are systematic differences in use and outcomes among various groups in society, and whether these differences result from financial or other barriers . Making progress towards greater equity in service provision requires understanding how well the health system is able to distribute services to populations and sub-populations on the basis of need. The 1984 Canada Health Act guarantees reasonable access to medically necessary care (provided by physicians and hospitals) to all Canadians. While this Act minimizes barriers to access that are financial in nature, geographic and other barriers (e.g., cultural) remain largely unaddressed.
Research reveals that geographic barriers represent a major source of inequitable access to care [3, 4], with health service utilization being inversely related to physical access (i.e., travel distance to obtain care) . It is also reasonably well accepted that the range and type of care provided varies by geography. Larger communities provide a broader range of services, while smaller urban areas and rural communities offer fewer service alternatives and/or reduced access to care. Some of the most often noted health service system deficiencies cited in smaller communities include the following: lower ratios of general practitioners and specialists per capita, fewer hospitals (and beds), reduced availability of allied health professionals (such as home support workers, therapists and counsellors), and limited respite care, palliative care and mental health care options [5, 6]. Human resource retention problems and practitioner isolation are also frequently noted .
From the inception of universal health insurance in Canada, provincial and territorial governments have been interested in enhancing equity in service provision, as well as citizen participation, accountability of decision-makers, service efficiency and cost-savings [8, 9]. These goals remain prominent. Regionalization, or the restructuring of decision-making authority and responsibility for health care delivery within local communities has been one of the primary mechanisms adopted to address barriers limiting equitable access to care during the past decade or more. In the province of British Columbia (BC), for example, the Royal (Seaton) Commission on Health Care and Costs 'Closer to Home' Report  and the 'New Directions for a Healthy BC' initiative  asserted the need for regionalization to address several goals including the integration and coordination of health services at the regional and community scale, devolved decision making and control to local communities and citizen empowerment .
In 1997, a profound set of changes altered the way that health care was organized and delivered in BC: the Health Authorities Act established 52 local health authorities made up of 11 Regional Health Boards (RHBs), 34 Community Health Councils (CHCs) and 7 Community Health Service Societies (CHSS) to look after health planning and service delivery across the province . RHBs were given responsibility for metropolitan or urban service provision, while CHCs and CHSSs were jointly responsible for planning and service delivery in rural and remote areas. In 2001, following a change in government, a new round of restructuring resulted in amalgamation of the province's health authorities into five larger regional health authorities and fifteen health service delivery areas, thereby re-centralizing power and authority with the provincial government and reducing local decision making .
Primary care is considered to be one pathway through which inequalities (geographic, economic, social) influence population health . Consequently, governments at all levels have identified primary care reform as a top priority to move the health system away from a sickness model and towards a wellness model supported within a population health framework [15, 16]. By definition, primary care is the first level, or the most common point of contact that individuals have with the health care system. The chief focus of primary care is the identification, diagnosis, treatment and management of health concerns .
Historically, primary care has been considered the domain of family physicians or general practitioners, working in group or solo practices, and acting as gatekeepers to the health care system. However, primary care is increasingly viewed more holistically, as care provided by nurses, social workers, therapists, family physicians and others in community health centre settings . Due to the historical development of primary care, reform efforts tend to focus on increasing access to care, incorporating multidisciplinary teams, improving information and technology systems, shifting physician remuneration from fee-for-service to alternative payment methods (e.g., salary or capitation), and enhancing coordination and integration with other health services (i.e., in institutions and in communities) [16, 17]. The integration of services, especially within primary care, is a keystone to health care reform. Research from Quebec emphasizes the importance of regionalization to provide the structure and leadership required for successful primary care reform initiatives .
To assess the adequacy, efficiency and quality of primary care within the broader health system, one indicator that researchers have focused on is 'avoidable' or 'preventable' hospitalizations [19–25]. With some qualifications, avoidable hospitalizations are said to represent a range of conditions for which hospitalization should be avoidable, provided that individuals have access to timely and effective primary care. More specifically, they represent a group of hospital episodes that could be treated in a primary care setting (i.e., a physician's office or community health clinic), provided that individuals are able to access these facilities at the appropriate time and the appropriate care is prescribed . Consequently, in any given geographic area, the expectation is that avoidable hospitalizations should be lower when people are receiving the primary care they require. Conversely, in areas where access to medical care is more limited, rates of avoidable hospitalizations tend to be higher .
Research findings have also confirmed that poor primary care, reduced access to care and diminished resources act together to increase avoidable or preventable hospitalizations . AHRs have been found to be inversely related to the supply of primary care physicians in both core metropolitan and rural communities . For example, Parchman and Culler report finding higher rates among persons living in US counties considered to have a shortage of primary care , while Lin et al. report higher AHRs in rural and remote areas compared with urban areas of BC . Regionalization and other health sector reforms appear to have had an impact on hospitalization rates in Canada in recent years. Hospitalization rates have declined, likely in conjunction with hospital and hospital bed closures implemented over the past three decades [30, 31]. From 1991/92 to 1996/97, the number of staffed beds in BC declined by 30%, the number of acute days per 1000 population declined by 28.8%, and the average length of stay declined by 12.9% . Some evidence suggests that AHRs also declined [4, 32, 33]. Yet, evidence about the extent to which these declines reflect the effects of regionalization and primary care reform and associated reductions in rural-urban inequities in care remains elusive.
While AHRs are an indicator of health system efficiency, it is also useful to consider how local populations (i.e., rural and urban) differ and to consider how they are being impacted by regionalization processes. Not surprisingly, health service system disadvantages that are present in small communities are exacerbated by population trends like demographic aging. For example, many small rural communities exhibit populations with high proportions of older adults that may be two to three times higher than provincial and national averages . Some studies suggest that rural residents experience a higher prevalence of chronic conditions and higher premature mortality rates compared to their urban counterparts, and also have higher death rates from unintentional injuries, chronic obstructive pulmonary disease, and suicide [35, 36]. It is also evident that the most rural and the most urban areas are of greatest concern in terms of the health status of local populations . Mainous and Kohrs studied rural and urban adults in Kentucky and found that rural dwellers age 65 and over had poorer health status, poorer physical and social functioning, and reduced mental health, although there were fewer significant differences when comparing the overall populations between rural and urban areas . A study comparing rural and urban older adults in Manitoba found no significant differences in self-rated health, but noted that rural elderly individuals were more likely to be satisfied with their health .
It may be more important to consider specific rural service contexts vis-à-vis the characteristics of particular rural populations (i.e., specific towns, cities and villages with higher proportions of seniors in their populations). The inconclusive evidence about whether rural populations are more or less healthy than their urban counterparts is partially explained by variations in regard to how 'rural' is defined, and given that the variables used to measure 'health' also vary. However, it may be sufficient to suggest that older persons living in rural areas are more vulnerable to regionalization given their situation of 'double-jeopardy,' that is, living in environments with reduced services at a time in their lives where they may have a greater need for care in relation to their age and health status . Benoit et al. conclude that access to rural maternity care was likely made worse by regionalization despite the fact that concern about the scarcity of providers in rural and remote communities predated regionalization . Generally speaking, the effectiveness of regionalization strategies in addressing geographic and other inequities in access to health care remains ambiguous and inconclusive .
This research examines trends in avoidable hospitalization rates as an indicator of primary care system access among adults aged 50 and over, living in rural and urban communities in British Columbia during a period of extensive regionalization. Two research questions are addressed: (1) What has happened to avoidable hospitalization rates, relative to non-avoidable hospitalization rates and total hospitalization rates, over time and during a period of health care restructuring and primary care reform initiatives in British Columbia, Canada?; and (2) To what extent do trends in avoidable hospitalization rates differ across rural and urban areas of the province? Specifically, has equity between rural and urban areas improved over time?
If there were no differences in equity of service provision, trends with regard to AHRs in rural and urban areas would be expected to overlap. On the basis of the literature and known trends in the availability of primary care, it is anticipated that AHRs would be higher in rural areas than in urban areas prior to reform. To the extent that regionalization efforts and primary care reform have been successful, one would expect to see this reflected in reduced AHRs over time. Additionally, if primary care reforms have been effective in reducing geographic inequities in access, one would expect to see decreasing AHRs, as well as greater reductions in AHRs in rural areas compared with urban areas over time.