A total of 58 patients (5.9%) reported Medicaid as the only source of insurance coverage compared with 84 persons (9.1%) with dual coverage (Medicare plus Medicaid) and 778 (85%) with other types of coverage (). The majority of individuals identified a rheumatologist as the primary SLE physician (74% of those with Medicaid insurance only, 68% with dual, and 81% with other insurance). As expected, because of Medicare coverage of end-stage renal disease, patients with dual coverage were much more likely to report a history of dialysis or transplant, and consequently these patients were more likely than the other groups to report a nephrologist as the primary SLE physician (11% versus 7% with Medicaid only and 4% with other insurance; P < 0.05).
Demographic and medical characteristics of study participants by insurance status*
Patients with only Medicaid insurance (hereafter referred to as Medicaid for simplicity) tended to be younger than patients with dual coverage or with other insurance (mean age 40.7 years, 46.7 years, and 46.4 years, respectively) and were more likely to live in a nonurban locale as categorized by census data. As might be predicted, patients with Medicaid coverage and dual coverage were less likely to be working and reported lower incomes than the group with other insurance. In general, the Medicaid group reported less formal education than the dual coverage group or the group with other insurance, although 37.9% of the Medicaid group reported attending trade school, vocational school, or some college.
In unadjusted analysis, the Medicaid and dual coverage groups reported higher SLE disease activity as measured by flare in the last 3 months and higher patient global assessments. Medicaid patients were more likely to have received intravenous steroids within the past year, but the 3 groups were equally likely to be taking oral steroids, cyclophosphamide, mycophenolate mofetil, or azathioprine.
In unadjusted analysis (), Medicaid patients reported traveling longer distances to see their primary SLE provider than those with Medicare, Medicare plus Medicaid, or other types of insurance coverage (mean distance 41.9 miles, 23.8 miles, 20.3 miles, and 24.3 miles, respectively; P < 0.05). For those who identified their primary SLE provider as a rheumatologist, Medicaid patients traveled longer distances than those with only Medicare, Medicare plus Medicaid, or other insurance (54.1 miles, 28.3 miles, 18.5 miles, and 26.9 miles, respectively; P < 0.05). Although the group with dual coverage more closely resembled the Medicaid group with respect to sociodemographic characteristics, for our final analyses we merged the dual coverage group and other insurance group to specifically examine access issues for the group with Medicaid as their sole insurance.
Average distance in miles traveled to systemic lupus erythematosus (SLE) physician by Medicaid status*
Adjustment for covariates such as SLE severity, age, ethnicity, urban status, and education reduced, but did not eliminate, the difference in distances traveled (). For all SLE providers, Medicaid patients traveled 11.5 more miles than those with other insurance, and for those seeing a rheumatologist, patients traveled 19.8 more miles (P < 0.05).
Multivariate linear analysis of distance (in excess miles traveled) to primary systemic lupus erythematosus (SLE) provider by Medicaid status*
We used flare in the last 3 months as a surrogate for SLE illness activity in our final model (). However, to determine if the results were sensitive to the choice of severity measure, we also modeled the results using our constructed measure of disease severity and patient global assessment (scale of 1 to 10) without significant alteration of results (data not shown).
A significant interaction between Medicaid only status, education, and distance to primary SLE provider was detected (P = 0.03). Specifically, Medicaid patients with higher than a high school education traveled longer distances to receive SLE care than those of similar educational background without Medicaid status and those with less than a high school education regardless of Medicaid status. This interaction was also seen in our subset group analysis of patients who reported a rheumatologist as their primary provider (P = 0.07) ().
For health care utilization, Medicaid individuals were equally as likely to have seen a rheumatologist within the past year () as those with other types of insurance, and no significant difference existed in the number of rheumatology visits between the 2 groups (mean excess visits = 0.95 for Medicaid; 95% confidence interval [95% CI] 0.02, 1.88). There was also no difference between groups with regard to utilization of other health care practitioners such as nephrologists, gynecologists, and pulmonologists (data not shown). Although both groups were equally as likely to have had ≥1 visits to a general practitioner in the past year, Medicaid participants were more likely to see a general practitioner for SLE-related symptoms (odds ratio 2.63; 95% CI 1.50, 4.61) and reported a mean of ~5 more visits to the general practitioner within the past year for SLE-related issues (P < 0.05).
Health care utilization differences between persons with and without Medicaid coverage*
Similarly, Medicaid patients were more likely to have had ≥1 visits to the emergency room for SLE within the last year and reported more visits to the emergency room for SLE (mean 0.89 more visits; P < 0.05). Our findings with respect to general physician and emergency room visits persisted when modeled for the subset of patients primarily cared for by a rheumatologist (data not shown). In multivariate analysis, controlling for SLE disease activity, age, education, race/ethnicity, urban status, and distance to SLE provider, the utilization patterns remained significant ().