Cost sharing and decreased branded oral anti-diabetic medication adherence among elderly Part D Medicare beneficiaries

Adherence to Oral Antidiabetic Drugs in Patients with Type 2 Diabetes: Systematic Review and Meta-Analysis

Poor adherence to oral antidiabetic drugs (OADs) in patients with type 2 diabetes (T2D) can lead to therapy failure and risk of complications. The aim of this study was to produce an adherence proportion to OADs and estimate the association between good adherence and good glycemic control in patients with T2D. We searched in MEDLINE, Scopus, and CENTRAL databases to find observational studies on therapeutic adherence in OAD users. We calculated the proportion of adherent patients to the total number of participants for each study and pooled study-specific adherence proportions using random effect models with Freeman-Tukey transformation. We also calculated the odds ratio (OR) of having good glycemic control and good adherence and pooled study-specific OR with the generic inverse variance method. A total of 156 studies (10,041,928 patients) were included in the systematic review and meta-analysis. The pooled proportion of adherent patients was 54% (95% confidence interval, CI: 51-58%). We observed a significant association between good glycemic control and good adherence (OR: 1.33; 95% CI: 1.17-1.51). This study demonstrated that adherence to OADs in patients with T2D is sub-optimal. Improving therapeutic adherence through health-promoting programs and prescription of personalized therapies could be an effective strategy to reduce the risk of complications.

Are patients more adherent to newer drugs?

The annual preventable cost from non-adherence in the US health care system amounts to $100 billion. While the relationship between adherence and the health system, the condition, patient characteristics and socioeconomic factors are established, the role of the heterogeneous productivity of drug treatment remains ambiguous. In this study, we perform cross-sectional retrospective analyses to study whether patients who use newer drugs are more adherent to pharmacotherapy than patients using older drugs within the same therapeutic class, accounting for unobserved heterogeneity at the individual level (e.g. healthy adherer bias). We use US Marketscan commercial claims and encounters data for 2008-2013 on patients initiating therapy for five chronic conditions. Productivity is captured by a drug's earliest Food and Drug Administration (FDA) approval year ("drug vintage") and by FDA" therapeutic potential" designation. We control for situational factors as promotional activity, copayments and distribution channel. A 10-year increase in mean drug vintage is associated with a 2.5 percentage-point increase in adherence. FDA priority status, promotional activity and the share of mail-order prescription fills positively influenced adherence, while co-payments had a negative effect. Newer drugs not only may be more effective in terms of clinical benefits, on average. They provide means to ease drug therapy to increase adherence levels as one component of drug quality, a notion physicians and pharmacy benefit managers should be aware of.

Association between Higher Generic Drug Use and Medicare Part D Star Ratings: An Observational Analysis

BACKGROUND

Increasing generic drug use, due to potential for cost savings and drug access, is a viable consideration for Medicare prescription drug plans to achieve high star ratings and improve quality of plan offerings for Medicare beneficiaries.

OBJECTIVE

To examine the association between contract-level proportion of generic drugs dispensed (pGDD) and Medicare Part D star ratings.

METHODS

This was a retrospective study of linked 2011 Medicare Part D star rating data with contract-level pGDD data. A total of 477 individual Medicare prescription contracts were included, representing 75% of total Prescription Drug Plans and more than 65% of total Medicare Advantage Prescription Drug Plans available by the end of 2010. Primary outcomes were Medicare Part D summary and domain star ratings (1-5 indicating lowest to highest performance), incorporating a range of quality measures for access, cost, beneficiary satisfaction, and health services outcomes and processes. Ordinal logistic regression models were used to examine associations between pGDD and Medicare Part D summary and domain star ratings, controlling for contract type and number of beneficiary enrollment.

RESULTS

Higher pGDD was associated with higher summary star ratings (adjusted odds ratio 1.08 with 95% confidence interval 1.04-1.12) and higher "member experience with drug plan" domain ratings (adjusted odds ratio 1.07 with 95% confidence interval 1.03-1.11).

CONCLUSIONS

Prescription formulary benefit design targeting increasing generic drug use appears to be associated with improved member experience and higher plan star ratings. Consideration may be given to incorporating pGDD into Medicare Part D star rating measures to improve quality of prescription plans.

Comparative adherence to diabetes drugs: An analysis of electronic health records and claims data

Non-adherence to medications is a major challenge in diabetes care. The objective of this brief report is to compare adherence rates for 6 major classes of diabetes medications: metformin, sulfonylurea, thiazolidinedione, basal insulin, DPP-4 inhibitors, and GLP-1 receptor agonists. We used a data source that linked electronic prescriptions with insurance claims to assess whether new electronic prescriptions for diabetes medications were followed by dispensing claims consistent with that prescription. After one year of follow-up, the daily medication possession probability (MPP) - a measure of overall adherence - at one year for sulfonylurea was 0.49 and for metformin was 0.46. Thiazolidinediones and basal insulin had a similar final daily MPP at 0.36 and 0.39, respectively, which was significantly lower than that for sulfonylurea or metformin (P < .05). GLP-1 receptor agonists and DPP-4 inhibitors were also comparable to one another at a final daily MPP of .30 and .21, respectively (P < .05 compared to any of the aforementioned drug classes). In summary, the rates at which diabetes drugs are prescribed, and the rates at which patients actually take them, differ substantially. Physicians should be aware of potentially significant challenges concerning adherence to newer agents.

Adherence, persistence, and treatment discontinuation with sitagliptin compared with sulfonylureas as add-ons to metformin: A retrospective cohort database study

BACKGROUND

Data are limited regarding adherence to dipeptidyl peptidase-4 inhibitors.

METHODS

The present retrospective cohort study of a claims database involved adults with type 2 diabetes mellitus, continuous enrollment for 12 months before the first prescription of add-on sitagliptin (SITA) or a sulfonylurea (SU) to metformin (MET) monotherapy (index date), and ≥45 days of MET coverage ≤90 days before the index date. The SITA and SU users were matched on duration of follow-up and propensity score (PS). Logistic regression analysis incorporated age, gender, comorbidities, and concomitant medications as independent variables.

RESULTS

Approximately 99 % of SITA patients were PS matched, resulting in 14 807 well-balanced PS-matched SITA/SU pairs. Mean proportion of days covered (PDC) was significantly higher for SITA (vs SU) + MET after 1 year (P < 0.001). Adherence (PDC ≥80 %) to SITA (vs SU) + MET was 59.1 % (vs 55.9 %; P < 0.001) at 1 year and 52.6 % (vs 49.9 %; P = 0.007) at 2 years. Using logistic regression models including out-of-pocket expense (OPE) as a covariate, we found improved mean PDC and adherence for SITA (vs SU) + MET. Numbers of patients who continued to use SITA (vs SU) + MET were significantly higher after Years 1, 2, and 3 (all P < 0.05).

CONCLUSIONS

Users of SITA + MET had significantly higher mean PDC, adherence, and persistence than those on SU + MET. These trends were robust to model alterations and were more marked when accommodating OPEs.

Myopic and Forward Looking Behavior in Branded Oral Anti-Diabetic Medication Consumption: An Example from Medicare Part D

We evaluate consumption responses to the non-linear Medicare Part D prescription drug benefit. We compare propensity-matched older patients with diabetes and Part D Standard or low-income-subsidy (LIS) coverage. We evaluate monthly adherence to branded oral anti-diabetics, with high end-of-year donut hole prices (>$200) for Standard patients and consistent, low (≤$6) prices for LIS. As an additional control, we examine adherence to generic anti-diabetics, with relatively low, consistent prices for Standard patients. If Standard patients are forward looking, they will reduce branded adherence in January, and LIS-Standard differences will be constant through the year. Contrary to this expectation, branded adherence is lower for Standard patients in January and diverges from LIS as the coverage year progresses. Standard-LIS generic adherence differences are minimal. Our findings suggest that seniors with chronic conditions respond myopically to the nonlinear Part D benefit, reducing consumption in response to high deductible, initial coverage and gap prices. Thus, when the gap is fully phased out in 2020, cost-related nonadherence will likely remain in the face of higher spot prices for more costly branded medications. These results contribute to studies of Part D plan choice and medication adherence that suggest that seniors may not make optimal healthcare decisions. Copyright © 2016 John Wiley & Sons, Ltd.

Patient-reported financial barriers to adherence to treatment in neurology

Objective

Many effective medical therapies are available for treating neurological diseases, but these therapies tend to be expensive and adherence is critical to their effectiveness. We used patient-reported data to examine the frequency and determinants of financial barriers to medication adherence among individuals treated for neurological disorders.

Patients and methods

Patients completed cross-sectional surveys on iPads as part of routine outpatient care in a neurology clinic. Survey responses from a 3-month period were collected and merged with administrative sources of demographic and clinical information (eg, insurance type). We explored the association between patient characteristics and patient-reported failure to refill prescription medication due to cost in the previous 12 months, termed here as “nonadherence”.

Results

The population studied comprised 6075 adults who were presented between July and September 2015 for outpatient neurology appointments. The mean age of participants was 56 (standard deviation: 18) years, and 1613 (54%) were females. The patients who participated in the surveys (2992, 49%) were comparable to nonparticipants with respect to gender and ethnicity but more often identified English as their preferred language (94% vs 6%, p<0.01). Among respondents, 9.8% (n=265) reported nonadherence that varied by condition. These patients were more frequently Hispanic (16.7% vs 9.8% white, p=0.01), living alone (13.9% vs 8.9% cohabitating, p<0.01), and preferred a language other than English (15.3% vs 9.4%, p=0.02).

Conclusion

Overall, the magnitude of financial barriers to medication adherence appears to vary across neurological conditions and demographic characteristics.

Giving formulary and drug cost information to providers and impact on medication cost and use: a longitudinal non-randomized study

BACKGROUND

Providers wish to help patients with prescription costs but often lack drug cost information. We examined whether giving providers formulary and drug cost information was associated with changes in their diabetes patients' drug costs and use. We conducted a longitudinal non-randomized evaluation of the web-based Prescribing Guide ( www.PrescribingGuide.com ), a free resource available to Hawaii's providers since 2006, which summarizes the formularies and copayments of six health plans for drugs to treat 16 common health conditions. All adult primary care physicians in Hawaii were offered the Prescribing Guide, and providers who enrolled received a link to the website and regular hardcopy updates.

METHODS

We analyzed prescription claims from a large health plan in Hawaii for 5,883 members with diabetes from 2007 (baseline) to 2009 (follow-up). Patients were linked to 299 "main prescribing" providers, who on average, accounted for >88 % of patients' prescriptions and drug costs. We compared changes in drug costs and use for "study" patients whose main provider enrolled to receive the Prescribing Guide, versus "control" patients whose main provider did not enroll to receive the Prescribing Guide.

RESULTS

In multivariate analyses controlling for provider specialty and clustering of patients by providers, both patient groups experienced similar increases in number of prescriptions (+3.2 vs. +2.7 increase, p = 0.24), and days supply of medications (+141 vs. +129 increase, p = 0.40) averaged across all drugs. Total and out-of-pocket drug costs also increased for both control and study patients. However, control patients showed higher increases in yearly total drug costs of $208 per patient (+$792 vs. +$584 increase, p = 0.02) and in 30-day supply costs (+$9.40 vs. +$6.08 increase, p = 0.03). Both groups experienced similar changes in yearly out-of-pocket costs (+$41 vs + $31 increase, p = 0.36) and per 30-day supply (-$0.23 vs. -$0.19 decrease, p = 0.996).

CONCLUSION

Giving formulary and drug cost information to providers was associated with lower increases in total drug costs but not with lower out-of-pocket costs or greater medication use. Insurers and health information technology businesses should continue to increase providers' access to formulary and drug cost information at the point of care.

Predicting Noninsulin Antidiabetic Drug Adherence Using a Theoretical Framework Based on the Theory of Planned Behavior in Adults With Type 2 Diabetes: A Prospective Study

Understanding the process behind noninsulin antidiabetic drug (NIAD) nonadherence is necessary for designing effective interventions to resolve this problem. This study aimed to explore the ability of the theory of planned behavior (TPB), which is known as a good predictor of behaviors, to predict the future NIAD adherence in adults with type 2 diabetes. We conducted a prospective study of adults with type 2 diabetes. They completed a questionnaire on TPB variables and external variables. Linear regression was used to explore the TPB's ability to predict future NIAD adherence, which was prospectively measured as the proportion of days covered by at least 1 NIAD using pharmacy claims data. The interaction between past NIAD adherence and intention was tested. The sample included 340 people. There was an interaction between past NIAD adherence and intention to adhere to the NIAD (P = 0.032). Intention did not predict future NIAD adherence in the past adherers and nonadherers groups, but its association measure was high among past nonadherers (β = 5.686, 95% confidence interval [CI] -10.174, 21.546). In contrast, intention was mainly predicted by perceived behavioral control both in the past adherers (β = 0.900, 95% CI 0.796, 1.004) and nonadherers groups (β = 0.760, 95% CI 0.555, 0.966). The present study suggests that TPB is a good tool to predict intention to adhere and future NIAD adherence. However, there was a gap between intention to adhere and actual adherence to the NIAD, which is partly explained by the past adherence level in adults with type 2 diabetes.

The Effects of Cost Sharing on Adherence to Medications Prescribed for Concurrent Use: Do Definitions Matter?

BACKGROUND

Accurate estimates of the effects of cost sharing on adherence to medications prescribed for use together, also called concurrent adherence, are important for researchers, payers, and policymakers who want to reduce barriers to adherence for chronic condition patients prescribed multiple medications concurrently. But measure definition consensus is lacking, and the effects of different definitions on estimates of cost-related nonadherence are unevaluated.

OBJECTIVES

To (a) compare estimates of cost-related nonadherence using different measure definitions and (b) provide guidance for analyses of the effects of cost sharing on concurrent adherence.

METHODS

This is a retrospective cohort study of Medicare Part D beneficiaries aged 65 years and older who used multiple oral antidiabetics concurrently in 2008 and 2009. We compared patients with standard coverage, which contains cost-sharing requirements in deductible (100%), initial (25%), and coverage gap (100%) phases, to patients with a low-income subsidy (LIS) and minimal cost-sharing requirements. Data source was the IMS Health Longitudinal Prescription Database. Patients with standard coverage were propensity matched to controls with LIS coverage. Propensity score was developed using logistic regression to model likelihood of Part D standard enrollment, controlling for sociodemographic and health status characteristics. For analysis, 3 definitions were used for unadjusted and adjusted estimates of adherence: (1) patients adherent to All medications; (2) patients adherent on Average; and (3) patients adherent to Any medication. Analyses were conducted using the full study sample and then repeated in analytic subgroups where patients used (a) 1 or more costly branded oral antidiabetics or (b) inexpensive generics only.

RESULTS

We identified 12,771 propensity matched patients with Medicare Part D standard (N = 6,298) or LIS (N = 6,473) coverage who used oral antidiabetics in 2 or more of the same classes in 2008 and 2009. In this sample, estimates of the effects of cost sharing on concurrent adherence varied by measure definition, coverage type, and proportion of patients using more costly branded drugs. Adherence rates ranged from 37% (All: standard patients using 1+ branded) to 97% (Any: LIS using generics only). In adjusted estimates, standard patients using branded drugs had 0.63 (95% CI = 0.57-0.70) and 0.70 (95% CI = 0.63-0.77) times the odds of concurrent adherence using All and Average definitions, respectively. The Any subgroup was not significant (OR = 0.89, 95% CI = 0.87-1.17). Estimates also varied in the full-study sample (All: OR = 0.79, 95% CI = 0.74-0.85; Average: OR = 0.83, 95% CI = 0.77-0.89) and generics-only subgroup, although cost-sharing effects were smaller. The Any subgroup generated no significant estimates.

CONCLUSIONS

Different concurrent adherence measure definitions lead to markedly different findings of the effects of cost sharing on concurrent adherence, with All and Average subgroups sensitive to these effects. However, when more study patients use inexpensive generics, estimates of these effects on adherence to branded medications with higher cost-sharing requirements may be diluted. When selecting a measure definition, researchers, payers, and policy analysts should consider the range of medication prices patients face, use a measure sensitive to the effects of cost sharing on adherence, and perform subgroup analyses for patients prescribed more medications for which they must pay more, since these patients are most vulnerable to cost-related nonadherence.

Description of anti-diabetic drug utilization pre- and post-formulary restriction of sitagliptin: findings from a national health plan

OBJECTIVE

Multi-tiered formularies are commonly used for controlling costs of prescription medications. Focused on type 2 diabetes mellitus (T2DM), this database study assessed drug utilization before and after a formulary restriction (2nd-3rd tier), and compared demographic and clinical characteristics of patients affected vs not by the restriction.

METHODS

Formulary restriction of sitagliptin (SITA) occurred July 1, 2012. The 'pre-period' was defined from January 1-June 30, 2012, the 'grace period' from July 1-September 30, 2012, and the 'post-period' from October 1, 2012-March 31, 2013. Patients from the OptumInsight database were included if diagnosed with T2DM, ≥18 years, had continuous enrollment, and had ≥2 prescriptions of SITA in the pre-period. Those who died or were aged ≥65 years in the post-period were excluded. Patients were grouped into SITA continuer and discontinuer cohorts based on SITA use in the post-period. Descriptive analyses assessed baseline patient characteristics and anti-hyperglycemic drug utilization in the pre- and post-periods.

RESULTS

In total, 23,477 patients met inclusion criteria. In the post-period, 36.1% (n = 8480) of patients discontinued SITA. Among SITA discontinuers, 44.1% switched to a preferred DPP-4 inhibitor, 9.2% switched to glucagon-like peptides-1 (GLP-1) or insulin, and 2.4% switched to metformin or sulfonylurea. Of the SITA discontinuers, 21.6% dropped SITA without replacement and 8.4% discontinued all diabetes medications. In the post-period, a greater proportion of SITA discontinuers used GLP-1 (12.6% vs 5.8%) and insulin (29.1% vs 20.9%) than continuers, or had some change in anti-hyperglycemic treatment (67.5% vs 22.1%). Baseline demographic and clinical characteristics were similar between SITA continuers and discontinuers, indicating a lack of an association with SITA discontinuation.

LIMITATIONS

This descriptive study used a non-controlled observational approach.

CONCLUSIONS

Following formulary change, 1/3 of patients discontinued SITA and 30% of discontinuers received less intensive anti-hyperglycemic treatment in the post-restriction period. Meanwhile, 44% of discontinuers switched to a new preferred DPP-4 inhibitor.

Impact of medicare part D plan features on use of generic drugs

BACKGROUND

Little is known about how Medicare Part D plan features influence choice of generic versus brand drugs.

OBJECTIVES

To examine the association between Part D plan features and generic medication use.

METHODS

Data from a 2009 random sample of 1.6 million fee-for-service, Part D enrollees aged 65 years and above, who were not dually eligible or receiving low-income subsidies, were used to examine the association between plan features (generic cost-sharing, difference in brand and generic copay, prior authorization, step therapy) and choice of generic antidepressants, antidiabetics, and statins. Logistic regression models accounting for plan-level clustering were adjusted for sociodemographic and health status.

RESULTS

Generic cost-sharing ranged from $0 to $9 for antidepressants and statins, and from $0 to $8 for antidiabetics (across 5th-95th percentiles). Brand-generic cost-sharing differences were smallest for statins (5th-95th percentiles: $16-$37) and largest for antidepressants ($16-$64) across plans. Beneficiaries with higher generic cost-sharing had lower generic use [adjusted odds ratio (OR)=0.97, 95% confidence interval (CI), 0.95-0.98 for antidepressants; OR=0.97, 95% CI, 0.96-0.98 for antidiabetics; OR=0.94, 95% CI, 0.92-0.95 for statins]. Larger brand-generic cost-sharing differences and prior authorization were significantly associated with greater generic use in all categories. Plans could increase generic use by 5-12 percentage points by reducing generic cost-sharing from the 75th ($7) to 25th percentiles ($4-$5), increasing brand-generic cost-sharing differences from the 25th ($25-$26) to 75th ($32-$33) percentiles, and using prior authorization and step therapy.

CONCLUSIONS

Cost-sharing features and utilization management tools were significantly associated with generic use in 3 commonly used medication categories.

Utilization and costs of medications associated with CKD mineral and bone disorder in dialysis patients enrolled in Medicare Part D

BACKGROUND

Information is limited regarding utilization patterns and costs for chronic kidney disease-mineral and bone disorder (CKD-MBD) medications in Medicare Part D-enrolled dialysis patients.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Annual cohorts of dialysis patients, 2007-2010.

PREDICTORS

Cohort year, low-income subsidy status, and dialysis provider.

OUTCOMES

Utilization and costs of prescription phosphate binders, oral and intravenous vitamin D analogues, and cinacalcet.

MEASUREMENTS

Using logistic regression, we calculated adjusted odds of medication use for low-income subsidy versus non-low-income subsidy patients and for patients from various dialysis organizations, and we report per-member-per-month and average out-of-pocket costs.

RESULTS

Phosphate binders (∼83%) and intravenous vitamin D (77.5%-79.3%) were the most commonly used CKD-MBD medications in 2007 through 2010. The adjusted odds of prescription phosphate-binder, intravenous vitamin D, and cinacalcet use were significantly higher for low-income subsidy than for non-low-income subsidy patients. Total Part D versus CKD-MBD Part D medication costs increased 22% versus 36% from 2007 to 2010. For Part D-enrolled dialysis patients, CKD-MBD medications represented ∼50% of overall net Part D costs in 2010.

LIMITATIONS

Inability to describe utilization and costs of calcium carbonate, an over-the-counter agent not covered under Medicare Part D; inability to reliably identify prescriptions filled through a non-Part D reimbursement or payment mechanism; findings may not apply to dialysis patients without Medicare Part D benefits or with Medicare Advantage plans, or to pediatric dialysis patients; could identify only prescription drugs dispensed in the outpatient setting; inability to adjust for MBD laboratory values.

CONCLUSIONS

Part D net costs for CKD-MBD medications increased at a faster rate than costs for all Part D medications in dialysis patients despite relatively stable use within medication classes. In a bundled environment, there may be incentives to shift to generic phosphate binders and reduce cinacalcet use.

Evaluation of discharge medication orders following automatic therapeutic substitution of commonly exchanged drug classes

OBJECTIVE

Automatic therapeutic substitution (ATS) is a mechanism that, upon patient hospitalization, prompts the pharmacist to exchange an equivalent formulary drug for a nonformulary medication, typically without prescriber contact. In facilities utilizing ATS, there is the possibility that physicians and patients may be unaware of the substitution, potentially leading to drug-drug interactions, therapeutic duplication, and/or increased patient expense following discharge should the original regimen not be resumed. The purpose of this study was to determine the frequency with which hospitalized patients subjected to an ATS protocol were not returned to outpatient drug therapy.

METHODS

A retrospective chart review of adult patients admitted to an academic medical center between January 1 and June 30, 2011, was conducted. Patients were included if they were admitted on angiotensin-converting enzyme (ACE) inhibitors, antidepressants, nonsedating antihistamines, histamine (H2) receptor antagonists, or proton pump inhibitors (PPIs), and were then prescribed a different agent via ATS. Admission and discharge medication reconciliation documents, dictated discharge summaries, and patient education documentation reports were reviewed for drug therapies and doses, as well as medication counseling evidence. The primary endpoint was the percentage of patients not returned to original outpatient therapy following ATS. Secondary endpoints included prescribing events in patients not returned to original therapy, the rate and source of drug therapy counseling at discharge, and the number of patients discharged on a potentially cost-prohibitive drug, defined as any drug available only as a branded product during the study period.

RESULTS

A total of 317 interventions were identified through review of pharmacy records. Of these, 47 patients (15%) were not returned to original outpatient therapy. Within this subsection, 15 patients (32%) were discharged on the substituted drug, eight patients (17%) resumed initial therapy but received a dosage adjustment from previous outpatient therapy, and three patients (6%) were discharged on a drug that was neither the substituted product nor the previous outpatient therapy. The remaining 21 patients had therapy discontinued (n = 12/47, 26%) or lacked documentation of discharge therapy (9/47, 19%). Nursing staff provided medication counseling to 288 of the 317 patients (91%). Overall, 51 patients (16%) were identified as receiving a cost-prohibitive drug.

CONCLUSION

Patients subject to ATS of commonly substituted drug classes were returned to their original outpatient drug therapy more than 85% of the time following inpatient hospitalizations, with similar rates of medication counseling at discharge. The prescribing of cost-prohibitive drugs has been identified as a potential area for pharmacist intervention at discharge.