Chapter 5. In: Gavin NI, Farrelly MC, ed. Evaluation of Medicaid managed care programs with 1915(b) waivers. Presented to HCFA Office of R&D. Rockville, MD, USA: Research Triangle Institute:5-1 to 5-65.
Research Triangle Institute, Rockville, MD, USA
The New Mexico Primary Care Network (PCN) provides a unique opportunity to study the impact of a mandatory primary care case management (PCCM) model in a predominantly rural State, among Supplemental Security Income (SSI) recipients and other aged and disabled Medicaid beneficiaries, and among two minority populations. Most early generation managed care models were in urban settings where Medicaid populations are concentrated and providers are more numerous. Therefore, little data exists on the success of these programs in rural areas. In addition, there is a dearth of information on how managed care impacts SSI-related Medicaid beneficiaries. The early Medicaid managed care programs typically were restricted to recipients of Aid to Families with Dependent Children (AFDC) and other AFDC-related beneficiaries. New Mexico’s PCN program is open to individuals enrolled under AFDC- and SSI-related eligibility groups and most poverty-related expansion beneficiaries (i.e., pregnant women and young children in poor and near-poor families). Finally, the New Mexico PCN program provides an opportunity to study the impact of a PCCM model for Native American and Hispanic beneficiaries. Approximately one half of all New Mexico Medicaid beneficiaries eligible for the PCN program in 1993 were Hispanic and another 11 percent were Native American.
To evaluate the PCN Section 1915(b) waiver in New Mexico, we used a quasi-experimental research design with both pre/post and contemporaneous comparisons of Medicaid claim data. The pre-period is calendar year 1990, the year just prior to the implementation of PCN, and the post-period is calendar year 1993. The experimental group consists of all Medicaid beneficiaries enrolled under PCN eligibility categories who resided in nonmetropolitan counties that implemented the program prior to 1993. The comparison group consists of similar Medicaid beneficiaries in nonmetropolitan counties that implemented the program after 1993.
We investigated PCN enrollment and disenrollment decisions and the success of the PCN program in achieving the following four goals: (1) to improve access to primary health care; (2) to promote the use of preventive care services; (3) to change patterns in service utilization; and (4) to control health care expenditures. We used several health service use measures from the claims data to provide evidence of the program’s success in meeting each of these goals. We compared the levels of and changes over time in these measures between the experimental and comparison groups. In addition, we used multivariate econometric techniques to control for demographic characteristics, Medicaid enrollment duration and category, and other selected factors independently influencing health service use. Separate analyses were performed for children (under 18 years of age), adults enrolled in Medicaid under the SSI-related eligibility criteria, and adults enrolled under AFDC-related and other eligibility criteria.