Impact of formulary restrictions on medication intensification in diabetes treatment.

OBJECTIVES: To explore formulary restrictions on noninsulin antihyperglycemic drugs (NIADs) in Medicare Part D plans and to estimate the impact of formulary restrictions on use of NIADs among low-income subsidy (LIS) recipient enrollees with type 2 diabetes (T2D) undergoing treatment intensification. STUDY DESIGN: Retrospective cohort study. METHODS: A cohort of 2919 LIS enrollees with T2D receiving metformin monotherapy during the first quarter of 2012 who intensified treatment later in the year was tracked to assess selection of and days' supply with sulfonylureas, dipeptidyl peptidase-4 (DPP-4) inhibitors, and other NIADs. We tested whether being enrolled in a Part D plan with significant formulary restrictions on sole-source brand name NIADs reduced the likelihood of receiving such agents and, if so, what the impact was on days of therapy with the second agent. A 2-part regression model was estimated with explanatory variables for plan-level restrictions and individual covariates. RESULTS: We found that 63% of study subjects initiated a sulfonylurea, 25% a DPP-4 inhibitor, and 12% another NIAD. Greater restrictions on DPP-4 inhibitors as a class were associated with small reductions in initiation of DPP-4 inhibitors and a concomitant increase in use of sulfonylureas, but neither effect was statistically significant. For individual DPP-4 inhibitors, step therapy requirements on sitagliptin and formulary exclusion of saxagliptin resulted in significant reductions in uptake of the specific drugs but had no significant impact on total days' supply of antihyperglycemic therapy. CONCLUSIONS: Part D formulary restrictions on sole-source brand name NIADs had little impact on patterns of treatment intensification for T2D among LIS recipients enrolled in Medicare Part D plans in 2012.

Adherence to Antipsychotic Therapy: Association With Hospitalization and Medicare Spending Among Part D Enrollees With Schizophrenia.

OBJECTIVE: This study examined relationships among antipsychotic adherence, hospitalization, and hospital expenditures in a sample of 13,861 Medicare Part D enrollees with schizophrenia. METHODS: Utilization and expenditure data were obtained from the Centers for Medicare and Medicaid Services Chronic Conditions Warehouse for 2011 and 2012. Adherence was measured with the proportion of days covered and stratified into four categories. Probit regressions and two-part generalized linear models were used to examine relationships between adherence in year 1 and outcomes in year 2. RESULTS: Adherence to antipsychotic therapy was associated with a significantly lower probability of psychiatric hospitalization and significantly lower psychiatric hospital expenditures, with the largest effect sizes observed for the most highly adherent beneficiaries. There was no relationship between antipsychotic adherence and hospitalizations or expenditures for nonpsychiatric conditions. CONCLUSIONS: Adherence to antipsychotics among Medicare Part D enrollees with schizophrenia was associated with significantly lower probability of psychiatric hospitalization and lower hospital expenditures.

The Impact of Coverage Restrictions on Antipsychotic Utilization Among Low-Income Medicare Part D Enrollees.

Prior research demonstrates substantial access problems associated with utilization management and formulary exclusions for antipsychotics in Medicaid, but the use and impact of coverage restrictions for these medications in Medicare Part D remains unknown. We assess the effect of coverage restrictions on antipsychotic utilization in Part D by exploiting a unique natural experiment in which low-income beneficiaries are randomly assigned to prescription drug plans with varying levels of formulary generosity. Despite considerable variation in use of coverage restrictions across Part D plans, we find no evidence that these restrictions significantly deter utilization or reduce access to antipsychotics for low-income beneficiaries.

Quantifying the Cost of Disability Transitions in Medicare.

OBJECTIVE: To investigate the impact of disability transitions on annual Medicare Part A and B cost. METHOD: We analyzed 6,385 community-dwelling beneficiaries who were continuously enrolled in fee-for-service Medicare Part A and B from 2008 to 2009. We estimated adjusted effects of disability transitions on Medicare cost using a generalized linear model. RESULTS: Transitions to more severe disability states were associated with significantly higher average annual Medicare cost ranging from US$2,639 to US$5,405. Lower spending levels were observed for beneficiaries with improvements in functioning. Beneficiaries who transitioned from severe to moderate activities of daily living (ADLs) disability cost significantly less (-US$6,045) than those who remained severely disabled. DISCUSSION: Interventions aimed at preventing disability progression and efforts to restore functional capacity are promising strategies for containing costs and generating savings for Medicare. Future research is needed to assess the longer term impact of disability in association with the progression of chronic conditions.

Redaction of Substance Abuse Claims in Medicare Research Files Affects Spending Outcomes for Nearly One in Five Beneficiaries with Serious Mental Illness.

OBJECTIVE: To assess the impact of substance abuse claims redaction on Medicare spending estimates for beneficiaries with serious mental illness. DATA SOURCES: The 2012 claims and unredacted beneficiary-level Medicare spending totals from CMS's Chronic Conditions Warehouse. STUDY DESIGN: We identified beneficiaries with claims affected by the redaction by comparing claims-based spending estimates to unredacted spending totals. Differences in characteristics of beneficiaries with and without redacted claims were examined in bivariate analyses. PRINCIPAL FINDINGS: Claims-based spending totals differed from unredacted totals for 19.7 percent of the cohort. Part A spending for those with redacted claims was underreported by 57.0 percent. Characteristics of beneficiaries with and without redacted claims differed significantly. CONCLUSIONS: Researchers who rely on Medicare claims to analyze spending outcomes for beneficiaries with serious mental illness should be aware of the potential for bias due to nonrandom redaction of substance abuse data.

Proximal Predictors of Long-Term Discontinuance with Noninsulin Antihyperglycemic Agents.

BACKGROUND: Noninsulin antihyperglycemic agents (NAAs) are the mainstay of treatment for type 2 diabetes, yet persistence in NAA use is suboptimal in many diabetes patients. Most of the research on NAA discontinuance has focused on sociodemographic characteristics and general health status, but such factors are inherently limited in explaining dynamic events such as discontinuance. OBJECTIVE: To assess the relative importance of static and proximal dynamic factors in explaining long-term NAA discontinuance among Medicare beneficiaries with diabetes. METHODS: Two sets of probability models were estimated to predict NAA discontinuance as a function of static variables (age, sex, race, original reason for Medicare entitlement, low-income subsidy and dual Medicare/Medicaid eligibility status, and disease burden) and 21 dynamic factors capturing month-by-month changes in drug use, health status, and use of medical services leading up to discontinuance (defined as month 0) and the previous 4 months (designated months -1 to -4) among 71,619 patients with diabetes enrolled in Medicare Part D plans in 2006-2008. RESULTS: Static variables explained just 1.2% of the variance in probability of NAA discontinuance compared with 14% for all variables combined. Key time-related predictors of NAA discontinuance included discontinuation with angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (ACEIs/ARBs) and statins, hypoglycemia, NAA usage gaps, insulin use, and discharge from hospitals and skilled nursing facilities (SNFs). The strongest significant predictors (P < 0.05) of NAA discontinuance were discontinuation with statins and ACEIs/ARBs in month 0 (predicted probabilities of 37% and 34%, respectively). Other variables that significantly increased the probability of NAA discontinuance by 10% or more were hypoglycemia in month 0 (14%) and month -1 (17%), discontinuance with ACEIs/ARBs in months -1 (15%) and -2 (10%), discontinuance with statins in month -1 (13%), and insulin use in month 0 (12%). Experiencing a previous gap in NAA therapy was associated with higher likelihood of discontinuance if the gap occurred in month -2 (10%) or month -4 (6%), but a gap in therapy in month -1 actually reduced the likelihood of discontinuance by 13%. Discharge from a hospital or SNF was consistently associated with higher probabilities of NAA discontinuance ranging between 4% and 10%, with higher probabilities occurring closer to month 0. CONCLUSIONS: A cascade of dynamic changes preceding discontinuance with NAA therapy among Medicare Part D enrollees with diabetes was observed between 2006 and 2008. Understanding that lack of persistence in drug use is a dynamic rather than a static phenomenon opens up new avenues for investigating and ultimately improving adherence behavior in the elderly. DISCLOSURES: This study was funded by Merck & Co. Huang and Raipathak are employees of Merck & Co. Brandt reports consultancy and speaker fees from Catapult, Omnicare, RAND, HRSA, CMS, and AGS Beers Criteria. Loh is currently employed at Touro College of Pharmacy. All other authors have no relevant potential conflicts of interest to disclose. Study concept and design were primarily contributed by Stuart, Quinn, and Brandt, along with Shen, Roberto, Hendrick, Huang, and Rajpathak. Shen, Loh, Hendrick, and Kim collected the data, and data interpretation was performed primarily by Stuart, Shen, and Roberto, assisted by Quinn, Brandt, Hendrick, Huang, and Rajpathak. The manuscript was written primarily by Stuart, with assistance from the other authors, and revised by Huang, Rajpathak, and Stuart, with assistance from the other authors.

Out-of-plan medication in Medicare Part D.

OBJECTIVES: To determine the extent to which Medicare Part D enrollees fill unadjudicated prescriptions for diabetes, hypertension, and hyperlipidemia medications outside of the Part D benefit. STUDY DESIGN: Retrospective analysis of prescriptions filled by community-dwelling beneficiaries continually enrolled in a Medicare Part D plan in 2009. METHODS: We used the Medicare Current Beneficiary Survey to compare self-reported prescription fills for oral antidiabetes medications, renin-angiotensin-aldosterone system inhibitors, and statins to adjudicated prescription drug event data recorded by Part D plan sponsors. For unadjudicated prescriptions with no evidence of Part D payment, we determined whether the fills were paid for in cash, filled through VA pharmacies or discount generic programs, or had other reported sources of coverage. RESULTS: A total of 6.2% of all prescriptions filled by Part D beneficiaries were unadjudicated, ranging from 5.3% of all oral antidiabetes medications to 6.8% of statins. Cash prescriptions accounted for more than half of all out-of-plan use, but we found little evidence of unadjudicated out-of-plan use of discount generics. Prescriptions filled at VA pharmacies and those with other reported sources of coverage each accounted for about 1% of total fills. CONCLUSIONS: Out-of-plan medication use accounts for a small share of total prescriptions filled by Part D beneficiaries. Nevertheless, CMS should continue to work with plan sponsors to develop initiatives that facilitate the collection of beneficiaries' complete utilization data, as a more complete reporting could improve the quality of care delivered to Part D enrollees.

Incident user cohorts for assessing medication cost-offsets.

OBJECTIVE: To develop and test incident drug user designs for assessing cost savings from statin use in diabetics. DATA SOURCE: Random 5 percent sample of Medicare beneficiaries, 2006-2008. STUDY DESIGN: Seven-step incident user design to assess impact of statin initiation on subsequent Medicare spending: (1) unadjusted pre/post initiation test; (2) unadjusted difference-in-difference (DID) with comparison series; (3) adjusted DID; (4) propensity score (PS)-matched DID with static and dynamic baseline covariates; (5) PS-matched DID by drug adherence strata; (6) PS-matched DID for high adherers controlling for healthy adherer bias; and (7) replication for ACE-inhibitor/ARB initiators. DATA COLLECTION/EXTRACTION METHODS: Subjects with prevalent diabetes and no statin use (January-June 2006) and statin initiation (July 2006-January 2008) compared to nonusers with a random "potential-initiation" month. Monthly Medicare spending tracked 24 months pre- and post-initiation. PRINCIPAL FINDINGS: Statistically significant savings in Medicare spending were observed beginning 7 months post-initiation for statins and 13 months post-initiation for ACEIs/ARBs. However, these savings were only observed for adherent patients in steps 5 and 6. CONCLUSIONS: Drug initiator designs are more robust to confounding than prevalent user designs in assessing cost-offsets from drug use but still require other adjustments and sensitivity analysis to ensure proper inference.

Should eligibility for medication therapy management be based on drug adherence?

BACKGROUND: Medicare Part D prescription drug plans must offer medication therapy management (MTM) services to qualified enrollees. Eligibility criteria used by plan sponsors are restrictive, and fewer than 10% of Part D enrollees receive MTM services. The extent to which plan criteria identify beneficiaries most at risk for suboptimal medication use is unknown. OBJECTIVES: To (a) evaluate potential underuse of and poor adherence to evidence-based medications used in the treatment of Medicare beneficiaries with diabetes, heart failure, and chronic obstructive pulmonary disease (COPD) over 3 years; (b) determine whether MTM eligibility criteria used by the modal Part D plan in 2011 (drug spending ≥ $3,000, ≥ 3 chronic conditions, ≥ 8 Part D medications) identified Part D enrollees at greatest risk for underuse of and poor adherence to these drugs; and (c) demonstrate how sensitive MTM eligibility is to variations in criteria levels. METHODS: Study subjects were selected from a 5% random sample of Part D enrollees with 1 or more of these diseases in 2006 and followed through 2008 or death. Longitudinal patterns of exposure and adherence to angiotensin-converting-enzyme inhibitor/angiotensin receptor blockers, beta-blockers, and COPD controller drugs were tracked comparing patterns for enrollees meeting/not meeting the modal 2011 MTM eligibility criteria. RESULTS: Use of evidence-based medication was consistently suboptimal for every disease cohort studied. Higher rates of exposure and adherence were observed among those with high drug spending taking multiple Part D drugs. Current MTM criteria were found to target beneficiaries with above average utilization of evidence-based medication and to exclude those with more problematic utilization patterns. We estimate that lowering the maximum required drug count from 8 to 2 would increase the percentage of beneficiaries eligible for MTM by two thirds. CONCLUSIONS: Our findings suggest that MTM eligibility criteria are not optimally targeted to capture underuse of and poor adherence to evidence-based medications. Policymakers should weigh the pros and cons of loosening restrictive MTM eligibility criteria to target patients with potentially greater needs.

Increasing Medicare part D enrollment in medication therapy management could improve health and lower costs.

Targeting efforts to improve medication adherence, especially among people with high health needs, can improve health and lower health care spending. To this end, Medicare requires that insurance plans that provide prescription drug (Part D) coverage offer specialized medication therapy management services to optimize medication use for enrollees with high drug costs, multiple chronic diseases, and multiple covered drugs. We analyzed a large random sample of Part D enrollees with diabetes, heart failure, and chronic obstructive pulmonary disease, to see whether poor adherence to recommended drugs was associated with higher Medicare costs. We found that beneficiaries with poor adherence had higher costs, ranging from $49 to $840 per month for patients with diabetes, for example. However, such beneficiaries were not uniformly more likely than others to be eligible for medication therapy management services. Aligning medication therapy management eligibility with a metric such as potentially preventable future costs holds promise for both improving the quality of care and reducing spending.

Plan choice and changes in access to care over time for SSI-eligible children with disabilities.

This paper analyzes how voluntary enrollment in the fee-for-service (FFS) system versus a partially capitated managed care plan affects changes in access to care over time for special needs children who receive Supplemental Security Income (SSI) due to a disability. Four indicators of access are evaluated, including specialty care, hospital care, emergency care, and access to a regular doctor. We employ the Heckman two-step estimation procedure to correct for the potential nonrandom selection bias linked to plan choice. The findings show that relative to their counterparts in the partially capitated managed care plan, SSI children enrolled in the FFS plan are significantly more likely to encounter an access problem during either of the time periods studied. Similarly, FFS enrollees are significantly more likely than partially capitated managed care participants to experience persistent access problems across three of the four dimensions of care. Possible explanations for the deterioration in access associated with FFS include the lack of case management services, lower reimbursement relative to the partially capitated managed care plan, and provider availability.