Data Sources

In this section, we describe the two databases linked by the parent study (i.e., the CSRS and Medicaid claims), the linking process, and the final dataset available for analysis, including how beneficiaries were enrolled in the MLIP and therefore our analytic dataset. As previously mentioned, the parent study linked NC Medicaid claims to records from NC’s CSRS from October 2009 through June 2013 for all beneficiaries enrolled in NC’s MLIP at some point between October 2010 and September 2012.74

4.2.1 Controlled Substances Reporting System (CSRS)

NC’s CSRS is a rich database that provides detailed information on each CS dispensed in the state through the aggregation of patient, provider, prescription, and pharmacy data.75 The NC legislature gave authority for the establishment of the CSRS in late 2005 through passage of the NC CSRS Act (NCGS 90-113.70).101 Under this Act, the purpose of the CSRS was defined as

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follows: “to improve the State's ability to identify controlled substance abusers or misusers and refer them for treatment, and to identify and stop diversion of prescription drugs in an efficient and cost-effective manner that will not impede the appropriate medical utilization of licit controlled substances.” Additionally, under this Act, the Drug Control Unit in the Division of Mental Health, Developmental Disabilities, and Substance Abuse Services in the NC DHHS was given the responsibility of administering the CSRS. The CSRS began operation on July 1, 2007, and all pharmacies dispensing CS (schedules II-V) in NC began reporting to the system

monthly.102 On August 1, 2008 pharmacy reporting increased to bimonthly, and as of, January 2, 2012, all pharmacies were required to report weekly. Prescribers and dispensers of CS are able to access information on CS to assist and help guide in the care of their patients.103 The following information is captured in the CSRS: unique identifiers for prescribers, dispensers, and patients; location (county-level) for dispensers and patients; the prescription’s quantity, days’ supply, indication of a new fill or refill, National Drug Code (NDC), and date prescribed and dispensed; and the age and gender of the beneficiary. While the CSRS has recently started collecting

information on the method of payment for each CS dispensed, this information was not available for this study.

4.2.2 Medicaid Claims

In 2015, 18% of the NC population was covered by Medicaid.104 Medicaid benefits were available to the following major groups of NC residents: 1) those who were pregnant and had household incomes up to about 200% of the federal poverty level; 2) parents with dependent children and household incomes up to about 45% of the federal poverty level (e.g., for a family of three, income cannot exceed $667/month); 3) blind persons with incomes below the poverty

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limit; 4) persons under the age of 65 years who were unable to work due to a severe disability that was expected to last at least 12 months and had incomes below the poverty limit; 5) persons aged 65 years or older with incomes below the poverty limit; 6) certain adults with long-term care needs (e.g., nursing care for older adults, others with long-term disabilities); and 7) children whose caregivers’ incomes fell below 133% or 210% of the poverty limit, depending on the child’s age.7 _{Those in the latter three groups were not included in our analyses (see Section 4.3).}

NC Medicaid claims data were obtained from the DMA’s Data Retrieval Information and Validation Engine (DRIVE).105 DRIVE is a Medicaid data warehouse that contains Medicaid eligibility information, prior authorization data, drug data, and other reference information. DRIVE is updated weekly, pulling information from the Medicaid Management Information System (MMIS), which processes claims for Medicaid.106 Data available through DRIVE includes beneficiary demographic information, beneficiaries’ periods of enrollment, and

adjudicated pharmacy and medical claims. Additionally, information on enrollment in the MLIP is recorded in DRIVE.

4.2.3 Linkage and Final Database

To link the DRIVE data to the CSRS data, the parent study hired a programmer external to the study. Manual linkage was performed using a standardized protocol that included

deterministically matching records based on the first five letters of the beneficiary’s last name, date of birth within six months, and the first two or three letters of the beneficiary’s first name. The protocol included rigorous data integrity checks and steps to help ensure that all of a given beneficiary’s records were linked and that issues such as minor misspellings or use of a common

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nickname would not prevent linkage. Once linked, dummy identifiers were assigned to all beneficiaries and identifying information was deleted prior to delivery to parent study staff.

The final linked data set contains comprehensive information on Medicaid beneficiaries enrolled in the MLIP at some point between October 2010 and September 2012, including all claims data and information on all CS dispensed to these beneficiaries, at any point from October 2009 through June 2013. Beneficiaries were enrolled in the MLIP on a monthly basis. While approximately 3,000 Medicaid beneficiaries were initially eligible for MLIP enrollment, the DMA only enrolled approximately 200 beneficiaries per month, due to resource constraints.69,107 Eligibility for the program was determined each month by a vendor who contracted with

Medicaid. The vendor examined the prescription dispensing history of all Medicaid beneficiaries for the previous two months and determined which beneficiaries met the eligibility criteria outlined in Table 1.2 (i.e., based on number of prescriptions obtained and prescribers visited). From those eligible, beneficiaries were then ranked and selected for enrollment using a

proprietary beneficiary review algorithm that factored in the number of prescriptions obtained, quantity received, days’ supply received, paid amounts, and distinct prescribers and pharmacies visited, combined with a clinical review process by pharmacists employed by the vendor. The vendor submitted its selected list of 200 beneficiaries each month to the DMA, and upon approval by the DMA, the vendor then sent each beneficiary a letter notifying them of their enrollment in the program. Enrolled beneficiaries were restricted to using one prescriber and one pharmacy location to obtain prescriptions categorized as opioids, benzodiazepines, or certain anxiolytics for a 12-month period. Beneficiaries were given 30 days to choose and nominate a preferred prescriber and pharmacy before restrictions began. If they did not respond to the DMA with their preferred prescriber and pharmacy, they were assigned one of each.

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