- Top of page
- MATERIALS AND METHODS
- Appendix: APPENDIX A: ESTIMATED INSUER' COSTS
Systemic lupus erythematosus (SLE) is a recurrent, relapsing disease typically affecting young women and occurring in ∼0.1–0.2% of the population. Due to the recurrent nature of the clinical manifestations of SLE, patient health, quality of life, and associated costs of the disease vary with time, depending on disease status. Although the literature on the economic impact of this disease is somewhat sparse, studies suggest that SLE results in significant direct and indirect costs for the individual and society (1, 2).
The relationship between ethnicity and outcomes in SLE has gained considerable attention in the past decade. Minority populations have a higher overall prevalence of SLE and display poorer outcomes. Alarcón and colleagues (3) found that Hispanics accrued damage more rapidly (as measured by the Systemic Lupus International Collaborative Clinics Damage Index) than African American or white populations. Some recent studies suggest that differences in outcomes may be the result of socioeconomic differences associated with minority populations, as opposed to biologic or genetic differences between the races (4). Regardless of the specific determinants, it is evident that minority populations appear to be more negatively impacted by SLE than white populations.
Health care coverage also plays an important role in health outcomes, as research suggests that lack of coverage results in decreased access to care and poor health outcomes (5, 6). Between 1996 and 1997, the percentage of nonelderly Americans without health care coverage increased from 17.7% to 18.3%, and adults ages 18–64 account for the majority of this increase (7). Employment status and income play a major role in determining an individual's likelihood of having health insurance, and factors such as ethnicity, citizenship, and language barriers are closely related to employment and income.
Medicaid provides health care coverage to patients who qualify based on income level or medical need. Disenrollment in this program is a serious issue, and research suggests that of those who are terminated from the program, the majority remain uninsured (8). National data indicate that one-third of all Hispanics in the United States are uninsured, which is 3 times the rate of the non-Hispanic white population. Hispanics that are Medicaid eligible often become ineligible upon securing employment. However, they are more likely to work in occupations (i.e., agriculture) that do not provide health care coverage, and therefore are more likely to remain uninsured (9).
Based on the evidence suggesting poorer outcomes for SLE minority populations, it is critical to investigate the factors contributing to poor outcomes to intervene with a strategy for improvement. Evidence suggests that the Hispanic population is more likely to lack health insurance than non-Hispanic white persons (10). Lack of health insurance inevitably impacts access to primary and specialty care providers, and subsequently, patient health outcomes and associated costs. In the present study, we investigated whether ethnicity was associated with differences in Medicaid eligibility, health care utilization, and direct medical costs.
- Top of page
- MATERIALS AND METHODS
- Appendix: APPENDIX A: ESTIMATED INSUER' COSTS
In this study, we explored eligibility patterns, utilization trends, and direct costs in a Medi-Cal lupus population. In general, Hispanic patients were less likely to have lengthy eligibility periods, whereas patients placed in the “other” category (primarily Asians and Pacific Islanders) were more likely to have longer eligibility periods. A partial explanation may be due to the Hispanic population in this sample being considerably younger than the other cohorts: 95% of individuals aged ≥65 years were insured through Medicare, but individuals <65 years were more likely to have multiple forms of insurance or no insurance at all (12). Younger individuals may need Medi-Cal assistance for only a short period of time until employment is secured, providing private insurance and/or raising the income level so that the patient no longer qualifies for aid.
Further investigation into differences in eligibility patterns suggests that Hispanic patients qualifying for Medi-Cal are different from other ethnicity groups in terms of aid program composition. They are more likely to qualify based on medical need/indigent status or under the OBRA program. Certain aid programs, such as OBRA, have restrictions on the length of eligibility. Although all of these factors contribute to shorter eligibility periods in Hispanics, they are far from complete. A survival analysis on the length of the first eligibility period controlling for age, sex, and aid program difference still showed significant differences in eligibility between Hispanics and other ethnicity groups.
Hispanic patients had the least utilization of Medi-Cal care services and generated lower total costs as the care of SLE progressed. Again, the younger age of the Hispanic cohort may have potentially contributed to this trend because younger patients tend to recover faster, are less likely to have major comorbid disorders, and treatment is generally less expensive due to fewer complications. Previous studies suggest an association between older age and greater damage accrual, most likely due to other comorbid disorders related to aging (13). However, one prior study revealed that older age was associated with lower costs, possibly due to reduction in SLE disease activity as patients age (especially those postmenopausal) (1). An analysis of total costs with longitudinal patient-level data was attempted using mixed-effect models to adjust for age, sex, dual eligibility, and aid program difference. However, the utilization trend for Hispanics still prevails after the adjustment. Although age and program type have demonstrated some contribution to these trends, further investigation is necessary to determine other influential factors.
Hispanic patients also generated significantly lower prescription drug costs than the other ethnicity groups. One explanation may be that the Hispanic cohort is receiving less optimal care than other cohorts. For example, the care providers may not be prescribing the newer (and possibly more effective) treatments that tend to be more costly (i.e., newer immunosuppressive agents). These findings may also be explained by the Hispanic cohort being younger and less likely to have other major comorbid disorders, resulting in lower prescription costs than other cohorts. Another explanation is that the Hispanic population may not be filling their prescriptions at the same rate as the other cohorts, and therefore generating less cost. The reasons for Hispanic differences in prescription drug utilization may prove to be critical in understanding the impact of differences in outcome for minority populations in this disease in which pharmacologic management is thought to be quite important.
This study is limited in that it utilizes Medi-Cal claims data with no access to clinical measures or patient-reported health outcomes. Therefore, we were unable to determine how the eligibility, utilization, and cost trends in this study relate to clinically important patient outcomes. Additionally, ethnicity information in administrative data may be flawed. Self-report information on ethnicity has only recently been added to Medicare files, and is still in the process of being updated. In the past, this race indicator has been somewhat unstable. There are also some limitations related to the mixed regression model applied in this study. The quarterly number of average total costs may not be normally distributed, and the variance structure of the random effect may be more complicated. Lastly, because Medicare does not consistently submit claims to Medi-Cal for the dually eligible population, we can not be sure we have complete claims history for this subset of patients. However, access to this missing data would only bolster our argument, as we would expect utilization and costs to further increase for this population, hence widening the gap between Hispanics and all other groups. A sensitivity test reveals the same pattern for patients who were not dually eligible and thus were less likely to be older than age 65.
Because SLE affects young women of reproductive age, assessing indirect costs is critical to understanding the impact of this disease. Sutcliffe and colleagues (1) found that direct costs accounted for one-third of the total costs for SLE patients in the UK, whereas the other two-thirds of the total costs were attributable to indirect costs. This highlights the importance of assessing indirect costs when investigating the economic and societal impact of SLE.
These preliminary data in a single state Medicaid program reinforce the importance of ethnicity in health care, particularly in lupus. Further studies are needed with additional complementary information concerning indirect costs. Furthermore, if it is true as previously suggested that Hispanic lupus patients accumulate damage faster than other minority groups (3), the fact that these patients appear to generate lower total direct costs suggests that the cause of this phenomenon needs to be explored further. The finding that Hispanic lupus patients have shorter eligibility periods than other cohorts should prompt further investigation into the reasons this population is likely to lose Medicaid fee-for-service eligibility, transition to Medicaid managed care, or obtain alternative health care coverage.