This study corroborates with other studies in showing that individual sociodemographic characteristics contribute to the number of physician visits for SLE in the year prior to interview. After adjustment, there are fewer visits with each increment in age, and almost 20% fewer for those participants with a high school education or less than for those with at least a college degree (10.1 versus 11.8 visits per year).
The first contribution of this study was to establish the substantial impact of the health care system itself on the number of physician visits for SLE. Persons receiving their care through an HMO have ~10% fewer physician visits than those seen in non-HMO settings (10.7 versus 11.8 visits). An even stronger effect occurred for the specialty of the main SLE physician, with persons with SLE seen by generalists reporting mean visits of 7.9 (95% CI 7.1– 8.7) for the condition in the 12 months prior to interview, compared with mean visits of 11.9 (95% CI 11.3–12.4) for those seen by rheumatologists, which is a difference of ~50% in relative terms even after taking individual demographics and health status into account.
Second, we found substantial effects of where one lives on the amount of care one receives for SLE. Therefore, even after adjusting for individual-level medical and sociodemographic characteristics, persons living in areas of concentrated poverty reported ~16% fewer physician visits for their SLE. There was also an effect of the HSAs on the number of physician visits for SLE beyond the effect of all other individual and community variables.
There are several ways to interpret the results indicating that community variables have effects beyond an individual’s own low SES on the quantity of physician visits. Communities with high concentrations of poverty may not provide the kinds of social networks that would allow access to specialists with experience in treating fairly rare conditions such as SLE. That such communities also often have high rates of crime may make it difficult to venture out to take advantage of the social networking opportunities that do exist. Alternatively, such communities may not be able to attract sufficient medical expertise to practice locally, and the primary care physicians that are there may be overburdened to the extent that they primarily provide basic care for common conditions.
The impact of community on access, whether due to residence in areas of concentrated poverty, particular HSAs, or both, may be unfortunate because it likely dovetails with problems of access to specialty care for SLE. In our study we found profound differences in the number of physician visits for SLE between those seen by generalist and specialist physicians. Moreover, there is accumulating evidence for rheumatic diseases in general (32
) and for SLE that care and outcomes differ among levels of specialization (11
), although part of the specialty effect may be due to experience rather than to training per se.
It is important to note that while population-based studies show differences in utilization across local areas, such differences may not reflect patient needs but rather local capacity for care (20
). The evidence also suggests that higher utilization does not necessarily result in better outcomes or quality of care (38
). The population-based findings are central to current health policy debate. However, the degree to which utilization beyond a certain level (not yet established empirically) benefits populations requiring ongoing specialty care for severe chronic conditions is still uncertain.
Our findings are limited by the use of self-report measurements for both the dependent and independent variables. The measure of SLE activity and our created proxy measure for SLE disease damage have not been psychometrically tested and may not fully adjust for disease activity or severity. A further limitation of this study is that the LOS data cohort is not a representative sample of people with SLE in the US. In particular, it has fewer people with very low SES and a higher proportion of people residing in highly urbanized areas, which may explain the lack of a significant effect of the area supply of subspecialists. However, the size and diversity of the LOS provides a broader picture of the SLE population compared with the typical SLE cohort based in an academic medical setting. While the LOS cohort is racially and ethnically diverse, it does not allow for stratified analyses of the various racial and ethnic groups.
Nonetheless, this study has established that there is a difference in the number of physician visits for SLE by SES, even after adjustment for other characteristics of the condition and the individual’s background. Readdressing this difference may be especially daunting when the individual lives in an area of concentrated poverty and/or an HSA with fewer resources. As several analysts have noted with respect to the efforts in Massachusetts to expand coverage for that state’s population, a policy that has been largely successful, it is difficult to secure equal access until the supply of health care providers grows to match the increased number with coverage (40
). The problem exposed by this study of heightened access problems for those living in select areas is likely to be even more daunting since expertise to treat an uncommon, complex, and severe condition such as SLE is not as widely disseminated as primary care (6
). As the era of increased medications approved specifically for SLE approaches, access to specialized expertise to treat the condition becomes even more important. The present study confirmed that the differences in the most basic measure of access, which is the number of physician visits for SLE over a year, are substantial and in part due to the individual’s background, as well as due to the specific nature of the community in which he or she resides.
In a prior study, we established that the community in which one resides affects outcomes in SLE independently of one’s own SES (8
). In the present study we showed that the community also affects health care utilization, as measured by the number of physician visits for SLE. The immediate next step in this research agenda is to establish whether there are differences among communities in the quality of care for SLE (44
) and then establish whether such differences in the quantity and quality of SLE care account for some of the outcome difference across communities already observed.