The American Journal of Managed Care October 2009
Effects of a Medicaid Prior Authorization Policy for Pregabalin
State Medicaid programs’ pregabalin prior authorization accomplished the objective of lower pregabalin utilization; the unintended effects were increased opioid use and increased disease-related healthcare costs.
Objective: To explore the effect of a prior authorization (PA) policy restricting access to pregabalin for the management of diabetic peripheral neuropathy (DPN) or postherpetic neuralgia (PHN) on the overall utilization of pharmacologic therapy and healthcare services among fee-for-service Medicaid plan beneficiaries.
Study Design: Retrospective claims data were obtained for 2005 and 2006 from 6 state Medicaid programs. Two states that had implemented pregabalin PAs beginning in 2006 were compared in terms of drug utilization and costs with 4 states having no such restrictions.
Methods: Patients at least 18 years old in a Medicaid fee-for-service program having a diagnosis of DPN or PHN and at least 1 claim for DPN- or PHN-specific pain medication were selected. Pharmacologic therapy, healthcare utilization, and expenditures were analyzed using bivariate statistics and generalized linear models in a difference-in-difference approach for comparing outcomes between cohorts year over year.
Results: The 2 cohorts included 424 patients in the restricted states and 5153 patients in the unrestricted states. Compared with the use in the unrestricted states, the probability of pregabalin use in the restricted states decreased by 4.0 percentage points (P = .02) from 2005 to 2006, while the probability of opioid use increased by 6.5 percentage points (P <.01).The DPN- or PHNrelated total healthcare costs were $418 higher for the restricted states versus the unrestricted states (P <.001).
Conclusion: Although the PA was shown to effectively control access to pregabalin, the overall effect was an increase in the use of opioids and alternative pain management therapies associated with increased disease-related healthcare costs.
(Am J Manag Care. 2009;15(9):e95-e102)
This study compared the effect on healthcare utilization and expenditures between 2 groups of state Medicaid programs based on whether the states had implemented a prior authorization (PA) intervention policy for pregabalin. The states with PA policies had significantly lower proportions of patients with any pregabalin use compared with the states without restricted access.
- The PA was associated with increased opioid use and significantly greater disease-specific costs.
- Although the PA accomplished the objective of controlling pregabalin usage, the overall effect was no net savings from the PA policy, with increased use of opioid and other alternative pain management therapies.
State Medicaid agencies commonly seek to control drug expenditures by enacting prior authorization (PA) policies that restrict access to medications unless specific criteria have been met, such as particular diagnoses, experience with other medications, or the presence of other health conditions. While PA policies enable access to medications according to the predetermined criteria, they create a barrier for patients and providers that effectively reduces prescribing for the target medications.1-5 Studies2-11 on Medicaid prescription drug cost-containment strategies have shown mixed evidence on the overall effect of PA policies, with some documenting enhanced efficiency and others showing negative clinical and economic effects.
Few studies have examined the effect of PA policies on patients diagnosed as having illnesses or conditions in which pain is the cardinal feature. Pain management often involves several different classes of pharmacologic agents (analgesics, antidepressants, anxiolytics, and others), as well as supportive medical therapy,12-14 encompassing a heterogeneous approach to care that extends the physician’s therapeutic options. Faced with the restrictions imposed by PA policies, physicians treating patients with these conditions may turn to other pharmacologic therapies and medical services to obtain the necessary degree of pain relief and to alleviate other effects of pain on patient well-being.8
Diabetic peripheral neuropathy (DPN), a complication of diabetes mellitus,15,16 and postherpetic neuralgia (PHN), a complication of herpes zoster infection,17,18 are 2 neuropathic pain conditions that share common pharmacologic treatments. These include opioids, antidepressants, and anticonvulsants18-22 such as the oral medication pregabalin (Lyrica [schedule V]), which is indicated for management of neuropathic pain associated with DPN and for management of PHN.23 Although pregabalin is one of the medications recommended as first-line treatment in DPN or PHN,21,22,24-27 several states have restricted Medicaid beneficiaries’ access to pregabalin by requiring a PA for reimbursement. The consequences of these restrictions remain unstudied. Potentially unintended clinical consequences may include the increased use of opioid analgesics and other medications (Table 1), as well as increases in the overall cost of care for these patients. This study explored the effect of restricted access to pregabalin on prescription medications used in DPN or PHN, as well as healthcare resource utilization and expenditures among the affected Medicaid populations of states with and without this PA policy.
The objective of this study was to evaluate the effect of a PA policy restricting access to pregabalin for the management of DPN or PHN in terms of the overall utilization of pharmacologic therapies, healthcare services, and direct medical costs for Medicaid beneficiaries with DPN or PHN in states with versus states without a PA policy.
The evaluated intervention was the introduction of a PA for reimbursement of pregabalin for the treatment of painful DPN or PHN. Retrospective claims data were obtained from 6 state Medicaid programs (2 that had implemented pregabalin PAs beginning in 2006 and 4 with no known restriction on reimbursement for pregabalin during 2005 or 2006). For each state, calendar year 2005 was the baseline (preintervention) period, and calendar year 2006 was the follow-up (postintervention) period. The study sample was limited to patients having a diagnosis of DPN or PHN at any time during the 2005-2006 study period. Evidence of treatment for symptomatic relief of DPN or PHN was also required to indicate painful DPN (all PHN is acknowledged as painful).
The study tested the following 3 hypotheses: (1) States with restrictions on pregabalin use (“restricted” states) have lower utilization of pregabalin relative to states without restrictions (“unrestricted” states). (2) Restrictions on pregabalin use are associated with increased use of other medications utilized in the management of painful DPN or PHN, including increases in the use of opioid and nonopioid analgesics. (3) Restrictions on pregabalin use are associated with increases in DPN- or PHN-related direct medical costs.
The 2005 and 2006 data of the Thomson Reuters MarketScan Medicaid Database, which includes complete longitudinal records of inpatient services, outpatient services, long-term care, and prescription drug claims, were used for this study. The restricted states included 1 large industrial state and 1 smaller rural state. The unrestricted states included 2 large industrial states and 2 smaller rural states. None of the states included in the study had both restricted and unrestricted plans. The states’ identities cannot be divulged because of contractual arrangements involved in acquiring their data.
Patients were required to be at least 18 years old and enrolled in a Medicaid fee-for-service program for the entire duration of 2005 and 2006. They were required to have at least 1 claim with an International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis code for DPN (250.6x or 357.2x) or PHN (053.1x) at any point during 2005-2006 and at least 1 claim for a medication used in treating painful DPN or PHN (Table 1) or for a pain intervention procedure (Table 2) within 60 days after any diagnosis of DPN or PHN. Patients with DPN or PHN were analyzed as a single group because of the small PHN sample size (in both cohorts, 96.2% of patients had only DPN).
Because most Medicaid dual-eligible beneficiaries started to receive their Medicare pharmacy benefits in 2006, we excluded Medicaid patients with Medicare coverage to represent the perspective of a contemporary Medicaid program. This study only included patients in fee-for-service plans because of Medicaid managed care plans’ not having complete reporting of medical claims. Patients were also excluded if they had resided in a long-term care facility for 90 days or longer, had any claims with an ICD-9-CM diagnosis code for epilepsy (345.xx or 780.39), had 1 inpatient or 2 outpatient nondiagnostic claims for cancer (140.xx-172.xx, 174.xx-208.xx, and 235.xx-239.xx [except for basal cell and squamous cell skin cancers and benign neoplasms]), or had undergone transplant surgery (codes available on request) at any point during 2005-2006.
Table 3 gives the incremental attrition associated with each of these criteria. The resulting cohort sample sizes are given for the restricted states and the unrestricted states.
The study period spanned 2005 and 2006. At the time of the study, the most recent Medicaid data availability was through December 2006; therefore, with the PA policy intervention being initiated in January 2006 for the restricted states, 2006 was the follow-up period, and 2005 was used as the baseline period. Pregabalin was approved for painful DPN and PHN in the United States in September 2005; however, the volume of claims for the few patients receiving pregabalin in 2005 was low (2.5% of patients [1.5 prescription claims per patient taking pregabalin]).
Diagnoses and pharmacologic therapy were derived from medical and pharmacy claims received according to service dates in 2005 and 2006. Medications for treating DPN or PHN were analyzed by drug class as summarized in Table 1 and for pregabalin individually. The DPN and PHN diagnoses and comorbidities were determined from nondiagnostic medical claims.
Healthcare utilization data included hospital admissions, length of stay, emergency department visits, physician office visits, other outpatient services, and numbers of outpatient prescriptions by drug class and for pregabalin individually. Healthcare expenditures were measured in 2006 Consumer Price Index–adjusted US dollars using the financial fields on administrative claims in the Medicaid database. Healthcare expenditures were based on the gross covered payments for all healthcare services or products (ie, the amount eligible for payment after applying pricing guidelines such as fee schedules and discounts, including deductibles, copayments, and coordination of benefits). Utilization and expenditure were measured for all medical and pharmacy claims. Medical claims were designated as DPN or PHN specific based on a diagnosis or procedures for DPN or PHN. Any diagnosis code entered for the claim was used.
Bivariate descriptive statistics were used to characterize the study population in terms of all key dependent, key independent, and control variables by year. All dependent and independent variables were compared in 2006 with the 2005 baseline within cohort, and then the year-over-year differences were contrasted between cohorts as follows: difference in difference (DID) = (restricted cohort 2006 − restrictedcohort 2005) − (unrestricted cohort 2006 − unrestricted cohort 2005). Χ2 Tests were used to evaluate differences for categorical variables and t tests for continuous variables. Tests for statistically significant differences between the restricted and unrestricted states’ differences in outcomes before and after the intervention (DID) were conducted. P <.05 represented statistical significance.