Comparison of measures of medication adherence from pharmacy dispensing and insurer claims data.

OBJECTIVE: Medication nonadherence is linked to worsened clinical outcomes and increased costs. Existing system-level adherence interventions rely on insurer claims for patient identification and outcome measurement, yet suffer from incomplete capture and lags in data acquisition. Data from pharmacies regarding prescription filling, captured in retail dispensing, may be more efficient. DATA SOURCES: Pharmacy fill and insurer claims data. STUDY DESIGN: We compared adherence measured using pharmacy fill data to adherence using insurer claims data, expressed as proportion of days covered (PDC) over 12 months. Agreement was evaluated using correlation/validation metrics. We also explored the relationship between adherence in both sources and disease control using prediction modeling. DATA EXTRACTION METHODS: Large pragmatic trial of cardiometabolic disease in an integrated delivery network. PRINCIPAL FINDINGS: Among 1113 patients, adherence was higher in pharmacy fill (mean = 50.0%) versus claims data (mean = 47.4%), although they had moderately high correlation (R = 0.57, 95% CI: 0.53-0.61) with most patients (86.9%) being similarly classified as adherent or nonadherent. Sensitivity and specificity of pharmacy fill versus claims data were high (0.89, 95% CI: 0.86-0.91 and 0.80, 95% CI: 0.75-0.85). Pharmacy fill-based PDC predicted better disease control slightly more than claims-based PDC, although the difference was nonsignificant. CONCLUSIONS: Pharmacy fill data may be an alternative to insurer claims for adherence measurement.

Using a Simple Prescription Gap to Determine Warfarin Discontinuation Can Lead to Substantial Misclassification.

BACKGROUND: Warfarin remains widely used and a key comparator in studies of other direct oral anticoagulants. As longer-than-needed warfarin prescriptions are often provided to allow for dosing adjustments according to international normalized ratios (INRs), the common practice of using a short allowable gap between dispensings to define warfarin discontinuation may lead to substantial misclassification of warfarin exposure. We aimed to quantify such misclassification and determine the optimal algorithm to define warfarin discontinuation. METHODS: We linked Medicare claims data from 2007 to 2014 with a multicenter electronic health records system. The study cohort comprised patients ≥65 years with atrial fibrillation and venous thromboembolism initiating warfarin. We compared results when defining warfarin discontinuation by (1) different gaps (3, 7, 14, 30, and 60 days) between dispensings and (2) having a gap ≤60 days or bridging larger gaps if there was INR ordering at least every 42 days (60_INR). Discontinuation was considered misclassified if there was an INR ≥2 within 7 days after the discontinuation date. RESULTS: Among 3,229 patients, a shorter gap resulted in a shorter mean follow-up time (82, 95, 117, 159, 196, and 259 days for gaps of 3, 7, 14, 30, 60, and 60_INR, respectively; p < 0.001). Incorporating INR (60_INR) can reduce misclassification of warfarin discontinuation from 68 to 4% (p < 0.001). The on-treatment risk estimation of clinical endpoints varied significantly by discontinuation definitions. CONCLUSION: Using a short gap between warfarin dispensings to define discontinuation may lead to substantial misclassification, which can be improved by incorporating intervening INR codes.

Frailty and Clinical Outcomes of Direct Oral Anticoagulants Versus Warfarin in Older Adults With Atrial Fibrillation : A Cohort Study.

BACKGROUND: The role of differing levels of frailty in the choice of oral anticoagulants for older adults with atrial fibrillation (AF) is unclear. OBJECTIVE: To examine the outcomes of direct oral anticoagulants (DOACs) versus warfarin by frailty levels. DESIGN: 1:1 propensity score-matched analysis of Medicare data, 2010 to 2017. SETTING: Community. PATIENTS: Medicare beneficiaries with AF who initiated use of dabigatran, rivaroxaban, apixaban, or warfarin. MEASUREMENTS: Composite end point of death, ischemic stroke, or major bleeding by frailty levels, defined by a claims-based frailty index. RESULTS: In the dabigatran-warfarin cohort (n = 158 730; median follow-up, 72 days), the event rate per 1000 person-years was 63.5 for dabigatran initiators and 65.6 for warfarin initiators (hazard ratio [HR], 0.98 [95% CI, 0.92 to 1.05]; rate difference [RD], -2.2 [CI, -6.5 to 2.1]). For nonfrail, prefrail, and frail persons, HRs were 0.81 (CI, 0.68 to 0.97), 0.98 (CI, 0.90 to 1.08), and 1.09 (CI, 0.96 to 1.23), respectively. In the rivaroxaban-warfarin cohort (n = 275 944; median follow-up, 82 days), the event rate per 1000 person-years was 77.8 for rivaroxaban initiators and 83.7 for warfarin initiators (HR, 0.98 [CI, 0.94 to 1.02]; RD, -5.9 [CI, -9.4 to -2.4]). For nonfrail, prefrail, and frail persons, HRs were 0.88 (CI, 0.77 to 0.99), 1.04 (CI, 0.98 to 1.10), and 0.96 (CI, 0.89 to 1.04), respectively. In the apixaban-warfarin cohort (n = 218 738; median follow-up, 84 days), the event rate per 1000 person-years was 60.1 for apixaban initiators and 92.3 for warfarin initiators (HR, 0.68 [CI, 0.65 to 0.72]; RD, -32.2 [CI, -36.1 to -28.3]). For nonfrail, prefrail, and frail persons, HRs were 0.61 (CI, 0.52 to 0.71), 0.66 (CI, 0.61 to 0.70), and 0.73 (CI, 0.67 to 0.80), respectively. LIMITATIONS: Residual confounding and lack of clinical frailty assessment. CONCLUSION: For older adults with AF, apixaban was associated with lower rates of adverse events across all frailty levels. Dabigatran and rivaroxaban were associated with lower event rates only among nonfrail patients. PRIMARY FUNDING SOURCE: National Institute on Aging.

Factors Associated With Generic Drug Uptake in the United States, 2012 to 2017.

OBJECTIVES: In the United States, brand-name prescription drugs remain expensive until market exclusivity ends and lower-cost generics become available. Delayed generic drug uptake may increase spending and worsen medication adherence and patient outcomes. We assessed recent trends and factors associated with generic uptake. METHODS: Among 227 drugs facing new generic competition from 2012 to 2017, we used a national claims database to measure generic uptake in the first and second year after generic entry, defined as the proportion of claims for a generic version of the drug. Using linear regression, we evaluated associations between generic uptake and key drug characteristics. RESULTS: Mean generic uptake was 66.1% (standard deviation 22.1%) in the first year and 82.7% (standard deviation 21.6%) in the second year after generic entry. From 2012 to 2017 generic uptake decreased 4.3% per year in the first year (95% confidence interval, 2.8%-5.8%, P < .001) and 3.2%/year in the second year (95% confidence interval, 1.2%-5.1%). Generic uptake was lower for injected than oral drugs in the first year (38.5% vs 70.0%, P < .001) and second year (50.3% vs 86.9%, P < .001). In the second year, generic uptake was higher among drugs with an authorized generic (86.1 vs 80.1%, P = .045) and those with ≥3 generic competitors (87.7% vs 78.6%, P = .055). CONCLUSION: Early generic uptake decreased over the past several years. This trend may adversely affect patients and increase prescription drug spending. Policies are needed to encourage generic competition, particularly among injected drugs administered in a hospital or clinic setting.

Estimating Rebates and Other Discounts Received by Medicare Part D.

Importance: Spending in Medicare Part D continues to increase. Yet, studies of Medicare Part D are plagued by a common limitation: none can fully account for confidential rebates and other discounts that drug manufacturers and pharmacies pay to Medicare Part D plans. Objectives: To review existing methods and to propose an approach for estimating rebates and other discounts received by Medicare Part D. Evidence Review: Publicly available data from the Boards of Trustees of the Federal Hospital Insurance and Federal Supplementary Medical Insurance Trust Funds, the Centers for Medicare & Medicaid Services, the Medicare Payment Advisory Commission, the Congressional Budget Office, the Government Accountability Office, and the Office of Inspector General. Findings: Existing methods for estimating rebates and other discounts in Medicare Part D have several limitations. This analysis used an approach that aims to improve on those methods. Based on this approach, estimated discounts on brand-name drugs increased in Medicare Part D from 25.4% of gross brand-name spending in 2014 to 37.3% in 2018. There was substantial variation between classes, with estimated 2016 discounts surpassing 50% for some drugs (eg, ophthalmologic and gastrointestinal tract agents) while remaining below 10% for others (eg, antineoplastic and immunologic agents). Between 2014 and 2018, estimated net Medicare Part D spending on prescription drugs increased by 21% from $99 billion to $119 billion. With increasing enrollment, estimated annual net spending per beneficiary remained stable, increasing by just 3% from $2622 to $2694, which was below the 6% rate of inflation during the same period. Conclusions and Relevance: Models that fail to properly account for increasing rebates and other discounts will overestimate Medicare Part D expenditures. Rigorous and transparent methods for estimating discounts are critical for understanding patterns in spending and developing new cost-containment strategies.

Screening Medications for Association with Progression to Wet Age-Related Macular Degeneration.

PURPOSE: There is an urgent need for treatments that prevent or delay development to advanced age-related macular degeneration (AMD). Drugs already on the market for other conditions could affect progression to neovascular AMD (nAMD). If identified, these drugs could provide insights for drug development targets. The objective of this study was to use a novel data mining method that can simultaneously evaluate thousands of correlated hypotheses, while adjusting for multiple testing, to screen for associations between drugs and delayed progression to nAMD. DESIGN: We applied a nested case-control study to administrative insurance claims data to identify cases with nAMD and risk-set sampled controls that were 1:4 variable ratio matched on age, gender, and recent healthcare use. PARTICIPANTS: The study population included cases with nAMD and risk set matched controls. METHODS: We used a tree-based scanning method to evaluate associations between hierarchical classifications of drugs that patients were exposed to within 6 months, 7 to 24 months, or ever before their index date. The index date was the date of first nAMD diagnosis in cases. Risk-set sampled controls were assigned the same index date as the case to which they were matched. The study was implemented using Medicare data from New Jersey and Pennsylvania, and national data from IBM MarketScan Research Database. We set an a priori threshold for statistical alerting at P ≤ 0.01 and focused on associations with large magnitude (relative risks ≥ 2.0). MAIN OUTCOME MEASURES: Progression to nAMD. RESULTS: Of approximately 4000 generic drugs and drug classes evaluated, the method detected 19 distinct drug exposures with statistically significant, large relative risks indicating that cases were less frequently exposed than controls. These included (1) drugs with prior evidence for a causal relationship (e.g., megestrol); (2) drugs without prior evidence for a causal relationship, but potentially worth further exploration (e.g., donepezil, epoetin alfa); (3) drugs with alternative biologic explanations for the association (e.g., sevelamer); and (4) drugs that may have resulted in statistical alerts due to their correlation with drugs that alerted for other reasons. CONCLUSIONS: This exploratory drug-screening study identified several potential targets for follow-up studies to further evaluate and determine if they may prevent or delay progression to advanced AMD.

Non-warfarin oral anticoagulant copayments and adherence in atrial fibrillation: A population-based cohort study.

BACKGROUND: In patients with atrial fibrillation, incomplete adherence to anticoagulants increases risk of stroke. Non-warfarin oral anticoagulants (NOACs) are expensive; we evaluated whether higher copayments are associated with lower NOAC adherence. METHODS: Using a national claims database of commercially-insured patients, we performed a cohort study of patients with atrial fibrillation who newly initiated a NOAC from 2012 to 2018. Patients were stratified into low (<$35), medium ($35-$59), or high (≥$60) copayments and propensity-score weighted based on demographics, insurance characteristics, comorbidities, prior health care utilization, calendar year, and the NOAC received. Follow-up was 1 year, with censoring for switching to a different anticoagulant, undergoing an ablation procedure, disenrolling from the insurance plan, or death. The primary outcome was adherence, measured by proportion of days covered (PDC). Secondary outcomes included NOAC discontinuation (no refill for 30 days after the end of NOAC supply) and switching anticoagulants. We compared PDC using a Kruskal-Wallis test and rates of discontinuation and switching using Cox proportional hazards models. RESULTS: After weighting patients across the 3 copayment groups, the effective sample size was 17,558 patients, with balance across 50 clinical and demographic covariates (standardized differences <0.1). Mean age was 62 years, 29% of patients were female, and apixaban (43%), and rivaroxaban (38%) were the most common NOACs. Higher copayments were associated with lower adherence (P < .001), with a PDC of 0.82 (Interquartile range [IQR] 0.36-0.98) among those with high copayments, 0.85 (IQR 0.41-0.98) among those with medium copayments, and 0.88 (IQR 0.41-0.99) among those with low copayments. Compared to patients with low copayments, patients with high copayments had higher rates of discontinuation (hazard ratio [HR] 1.13, 95% confidence interval [CI] 1.08-1.19; P < .001). CONCLUSIONS: Among atrial fibrillation patients newly initiating NOACs, higher copayments in commercial insurance were associated with lower adherence and higher rates of discontinuation in the first year. Policies to lower or limit cost-sharing of important medications may lead to improved adherence and better outcomes among patients receiving NOACs.

Empirical assessment of case-based methods for identification of drugs associated with acute liver injury in the French National Healthcare System database (SNDS).

PURPOSES: Drug induced acute liver injury (ALI) is a frequent cause of liver failure. Case-based designs were empirically assessed and calibrated in the French National claims database (SNDS), aiming to identify the optimum design for drug safety alert generation associated with ALI. METHODS: All cases of ALI were extracted from SNDS (2009-2014) using specific and sensitive definitions. Positive and negative drug controls were used to compare 196 self-controlled case series (SCCS), case-control (CC), and case-population (CP) design variants, using area under the receiver operating curve (AUC), mean square error (MSE) and coverage probability. Parameters that had major impacts on results were identified through logistic regression. RESULTS: Using a specific ALI definition, AUCs ranged from 0.78 to 0.94, 0.64 to 0.92 and 0.48 to 0.85, for SCCS, CC and CP, respectively. MSE ranged from 0.12 to 0.40, 0.22 to 0.39 and 1.03 to 5.29, respectively. Variants adjusting for multiple drug use had higher coverage probabilities. Univariate regressions showed that high AUCs were achieved with SCCS using exposed time as the risk window. The top SCCS variant yielded an AUC = 0.93 and MSE = 0.22 and coverage = 86%, with 1/7 negative and 13/18 positive controls presenting significant estimates. CONCLUSIONS: SCCS adjusting for multiple drugs and using exposed time as the risk window performed best in generating ALI-related drug safety alert and providing estimates of the magnitude of the risk. This approach may be useful for ad-hoc pharmacoepidemiology studies to support regulatory actions.

Differences in characteristics of Medicare patients treated by ophthalmologists and optometrists.

PURPOSE: To quantify differences in the age, gender, race, and clinical complexity of Medicare beneficiaries treated by ophthalmologists and optometrists in each of the United States. DESIGN: Cross-sectional study based on publicly accessible Medicare payment and utilization data from 2012 through 2017. METHODS: For each ophthalmic and optometric provider, demographic information of treated Medicare beneficiaries was obtained from the Medicare Provider Utilization and Payment Data from the Centers for Medicare and Medicaid Services (CMS) for the years 2012 through 2017. Clinical complexity was defined using CMS Hierarchical Condition Category (HCC) coding. RESULTS: From 2012 through 2017, ophthalmologists in every state treated statistically significantly older beneficiaries, with the greatest difference (4.99 years in 2014) between provider groups seen in Rhode Island. In most states there was no gender difference among patients treated by the providers but in 46 states ophthalmologists saw a more racially diverse group of beneficiaries. HCC risk score analysis demonstrated that ophthalmologists in all 50 states saw more medically complex beneficiaries and the differences were statistically significant in 47 states throughout all six years. CONCLUSIONS: Although there are regional variations in the characteristics of patients treated by ophthalmologists and optometrists, ophthalmologists throughout the United States manage older, more racially diverse, and more medically complex Medicare beneficiaries.

Preferences for and experiences with pill appearance changes: national surveys of patients and pharmacists.

OBJECTIVES: To better understand patients' and pharmacists' preferences for and experiences with changes in pill appearance (size, shape, color, and markings). STUDY DESIGN: Cross-sectional. METHODS: We conducted independent national surveys of patients 50 years and older taking generic drugs for depression, diabetes, epilepsy, HIV, hyperlipidemia, or hypertension and of licensed pharmacists practicing in chain, franchise, or independent pharmacies. Responses were collected between January and April 2016. RESULTS: Of 1000 patient respondents (30% response rate), most reported experiencing changes in pill appearance (51%) and preferred to be notified about them (82%), but less than half recalled being notified (verbally: 36%; via sticker: 45%). Among patients who reported experiencing a change, 12% reported stopping their medication or using it less frequently. Of 710 pharmacist respondents (33% response rate), many reported changes in pill appearance occurring frequently in their pharmacies (47% reported that changes occurred 6 or more times per month) and more than three-fourths reported notifying patients about them often (verbally: 88%; via sticker: 77%). CONCLUSIONS: Our findings reveal opportunities to improve patients' experiences with pill appearance changes through better notification practices and patient education.

Comparison of a new 3-item self-reported measure of adherence to medication with pharmacy claims data in patients with cardiometabolic disease.

BACKGROUND: Less than half of patients with cardiometabolic disease consistently take prescribed medications. While health insurers and some delivery organizations use claims to measure adherence, most clinicians do not have access during routine interactions. Self-reported scales exist, but their practical utility is often limited by length or cost. By contrast, the accuracy of a new 3-item self-reported measure has been demonstrated in individuals with HIV. We evaluated its concordance with claims-based adherence measures in cardiometabolic disease. METHODS: We used data from a recently-completed pragmatic trial of patients with cardiometabolic conditions. After 12 months of follow-up, intervention subjects were mailed a survey with the 3-item measure that queries about medication use in the prior 30 days. Responses were linearly transformed and averaged. Adherence was also measured in claims in month 12 and months 1-12 of the trial using proportion of days covered (PDC) metrics. We compared validation metrics for non-adherence for self-report (average <0.80) compared with claims (PDC <0.80). RESULTS: Of 459 patients returning the survey (response rate: 43.5%), 50.1% were non-adherent in claims in month 12 while 20.9% were non-adherent based on the survey. Specificity of the 3-item metric for non-adherence was high (month 12: 0.83). Sensitivity was relatively poor (month 12: 0.25). Month 12 positive and negative predictive values were 0.59 and 0.52, respectively. CONCLUSIONS: A 3-item self-reported measure has high specificity but poor sensitivity for non-adherence versus claims in cardiometabolic disease. Despite this, the tool could help target those needing adherence support, particularly in the absence of claims data.

Risk of sudden cardiac arrest and ventricular arrhythmia with sulfonylureas: An experience with conceptual replication in two independent populations.

Sulfonylureas are commonly used to treat type 2 diabetes mellitus. Despite awareness of their effects on cardiac physiology, a knowledge gap exists regarding their effects on cardiovascular events in real-world populations. Prior studies reported sulfonylurea-associated cardiovascular death but not serious arrhythmogenic endpoints like sudden cardiac arrest (SCA) or ventricular arrhythmia (VA). We assessed the comparative real-world risk of SCA/VA among users of second-generation sulfonylureas: glimepiride, glyburide, and glipizide. We conducted two incident user cohort studies using five-state Medicaid claims (1999-2012) and Optum Clinformatics commercial claims (2000-2016). Outcomes were SCA/VA events precipitating hospital presentation. We used Cox proportional hazards models, adjusted for high-dimensional propensity scores, to generate adjusted hazard ratios (aHR). We identified 624,406 and 491,940 sulfonylurea users, and 714 and 385 SCA/VA events, in Medicaid and Optum, respectively. Dataset-specific associations with SCA/VA for both glimepiride and glyburide (vs. glipizide) were on opposite sides of and could not exclude the null (glimepiride: aHRMedicaid 1.17, 95% CI 0.96-1.42; aHROptum 0.84, 0.65-1.08; glyburide: aHRMedicaid 0.87, 0.74-1.03; aHROptum 1.11, 0.86-1.42). Database differences in data availability, populations, and documentation completeness may have contributed to the incongruous results. Emphasis should be placed on assessing potential causes of discrepancies between conflicting studies evaluating the same research question.

Empirical assessment of case-based methods for identification of drugs associated with upper gastrointestinal bleeding in the French National Healthcare System database (SNDS).

PURPOSE: Upper gastrointestinal bleeding (UGIB) is a severe and frequent drug-related event. In order to enable efficient drug safety alert generation in the French National Healthcare System database (SNDS), we assessed and calibrated empirically case-based designs to identify drug associated with UGIB risk. METHODS: All cases of UGIB were extracted from SNDS (2009-2014) using two definitions. Positive and negative drug controls were used to compare 196 self-controlled case series (SCCS), case-control (CC) and case-population (CP) design variants. Each variant was evaluated in a 1/10th population sample using area under the receiver operating curve (AUC) and mean square error (MSE). Parameters that had major impacts on results were identified through logistic regression. Optimal designs were replicated in the unsampled population. RESULTS: Using a specific UGIB definition, AUCs ranged from 0.64 to 0.80, 0.44 to 0.61 and 0.50 to 0.67, for SCCS, CC and CP, respectively. MSE ranged from 0.07 to 0.39, 0.83 to 1.33 and 1.96 to 4.6, respectively. Univariate regressions showed that high AUCs were achieved with SCCS with multiple drug adjustment and a 30-day risk window starting at exposure. The top-performing SCCS variant in the unsampled population yielded an AUC = 0.84 and MSE = 0.14, with 10/36 negative controls presenting significant estimates. CONCLUSIONS: SCCS adjusting for multiple drugs and using a 30-day risk window has the potential to generate UGIB-related alerts in the SNDS and hypotheses on its potential population impact. Negative control implementation highlighted that low systematic error was generated but that protopathic bias and confounding by indication remained unaddressed issues.

Using Data From Routine Care to Estimate the Effectiveness and Potential Limitations of Outcomes-Based Contracts for Diabetes Medications.

OBJECTIVES: Outcomes-based contracts tie rebates and discounts for expensive drugs to outcomes. The objective was to estimate the utility of outcomes-based contracts for diabetes medications using real-world data and to identify methodologic limitations of this approach. METHODS: A population-based cohort study of adults newly prescribed a medication for diabetes with a publicly announced outcomes-based contract (ie, exenatide microspheres ["exenatide"], dulaglutide, or sitagliptin) was conducted. The comparison group included patients receiving canagliflozin or glipizide. The primary outcome was announced in the outcomes-based contract: the percentage of adults with a follow-up hemoglobin A1C <8% up to 1 year later. Secondary outcomes included the percentage of patients diagnosed with hypoglycemia and the cost of a 1-month supply. RESULTS: Thousands of adults newly filled prescriptions for exenatide (n = 5079), dulaglutide (n = 6966), sitagliptin (n = 40 752), canagliflozin (n = 16 404), or glipizide (n = 59 985). The percentage of adults subsequently achieving a hemoglobin A1C below 8% ranged from 83% (dulaglutide, sitagliptin) to 71% (canagliflozin). The rate of hypoglycemia was 25 per 1000 person-years for exenatide, 37 per 1000 person-years for dulaglutide, 28 per 1000 person-years for sitagliptin, 18 per 1000 person-years for canagliflozin, and 34 per 1000 person-years for glipizide. The cash price for a 1-month supply was $847 for exenatide, $859 for dulaglutide, $550 for sitagliptin, $608 for canagliflozin, and $14 for glipizide. CONCLUSION: Outcomes-based pricing of diabetes medications has the potential to lower the cost of medications, but using outcomes such as hemoglobin A1C may not be clinically meaningful because similar changes in A1C can be achieved with generic medications at a far lower cost.

Rates and Costs of Dispensing Naloxone to Patients at High Risk for Opioid Overdose in the United States, 2014-2018.

INTRODUCTION: Clinical practice guidelines recommend co-prescribing naloxone to patients at high risk of opioid overdose, but few such patients receive naloxone. High costs of naloxone may contribute to limited dispensing. OBJECTIVE: The aim of this study was to evaluate rates and costs of dispensing naloxone to patients receiving opioid prescriptions and at high risk for opioid overdose. METHODS: Using claims data from a large US commercial insurance company, we conducted a retrospective cohort study of new opioid initiators between January 2014 and December 2018. We identified patients at high risk for overdose defined as a diagnosis of opioid use disorder, prior overdose, an opioid prescription of ≥ 50 mg morphine equivalents/day for ≥ 90 days, and/or concurrent benzodiazepine prescriptions. RESULTS: Among 5,292,098 new opioid initiators, 616,444 (12%) met criteria for high risk of overdose during follow-up, and, of those, 3096 (0.5%) were dispensed naloxone. The average copayment was US$24.83 for naloxone (standard deviation [SD] 67.66) versus US$9.74 for the index opioid (SD 19.75). The average deductible was US$6.18 for naloxone (SD 27.32) versus US$3.74 for the index opioid (SD 25.56), with 94% and 88% having deductibles of US$0 for their naloxone and opioid prescriptions, respectively. The average out-of-pocket cost was US$31.01 for naloxone (SD 73.64) versus US$13.48 for the index opioid (SD 34.95). CONCLUSIONS: Rates of dispensing naloxone to high risk patients were extremely low, and prescription costs varied greatly. Since improving naloxone's affordability may increase access, whether naloxone's high cost is associated with low dispensing rates should be evaluated.

Effectiveness and Safety of Apixaban Compared With Rivaroxaban for Patients With Atrial Fibrillation in Routine Practice: A Cohort Study.

Background: Apixaban and rivaroxaban are the most commonly prescribed direct oral anticoagulants for adults with atrial fibrillation, but head-to-head data comparing their safety and effectiveness are lacking. Objective: To compare the safety and effectiveness of apixaban versus rivaroxaban for patients with nonvalvular atrial fibrillation. Design: New-user, active-comparator, retrospective cohort study. Setting: A U.S. nationwide commercial health care claims database from 28 December 2012 to 1 January 2019. Patients: Adults newly prescribed apixaban (n = 59 172) or rivaroxaban (n = 40 706). Measurements: The primary effectiveness outcome was a composite of ischemic stroke or systemic embolism. The primary safety outcome was a composite of intracranial hemorrhage or gastrointestinal bleeding. Results: 39 351 patients newly prescribed apixaban were propensity score matched to 39 351 patients newly prescribed rivaroxaban. Mean age was 69 years, 40% of patients were women, and mean follow-up was 288 days for new apixaban users and 291 days for new rivaroxaban users. The incidence rate of ischemic stroke or systemic embolism was 6.6 per 1000 person-years for adults prescribed apixaban compared with 8.0 per 1000 person-years for those prescribed rivaroxaban (hazard ratio [HR], 0.82 [95% CI, 0.68 to 0.98]; rate difference, 1.4 fewer events per 1000 person-years [CI, 0.0 to 2.7]). Adults prescribed apixaban also had a lower rate of gastrointestinal bleeding or intracranial hemorrhage (12.9 per 1000 person-years) compared with those prescribed rivaroxaban (21.9 per 1000 person-years), corresponding to an HR of 0.58 (CI, 0.52 to 0.66) and a rate difference of 9.0 fewer events per 1000 person-years (CI, 6.9 to 11.1). Limitation: Unmeasured confounding, incomplete laboratory data. Conclusion: In routine care, adults with atrial fibrillation prescribed apixaban had a lower rate of both ischemic stroke or systemic embolism and bleeding compared with those prescribed rivaroxaban. Primary Funding Source: Division of Pharmacoepidemiology and Pharmacoeconomics, Brigham and Women's Hospital.

Empirical assessment of case-based methods for drug safety alert identification in the French National Healthcare System database (SNDS): Methodology of the ALCAPONE project.

OBJECTIVES: To introduce the methodology of the ALCAPONE project. BACKGROUND: The French National Healthcare System Database (SNDS), covering 99% of the French population, provides a potentially valuable opportunity for drug safety alert generation. ALCAPONE aimed to assess empirically in the SNDS case-based designs for alert generation related to four health outcomes of interest. METHODS: ALCAPONE used a reference set adapted from observational medical outcomes partnership (OMOP) and Exploring and Understanding Adverse Drug Reactions (EU-ADR) project, with four outcomes-acute liver injury (ALI), myocardial infarction (MI), acute kidney injury (AKI), and upper gastrointestinal bleeding (UGIB)-and positive and negative drug controls. ALCAPONE consisted of four main phases: (1) data preparation to fit the OMOP Common Data Model and select the drug controls; (2) detection of the selected controls via three case-based designs: case-population, case-control, and self-controlled case series, including design variants (varying risk window, adjustment strategy, etc.); (3) comparison of design variant performance (area under the ROC curve, mean square error, etc.); and (4) selection of the optimal design variants and their calibration for each outcome. RESULTS: Over 2009-2014, 5225 cases of ALI, 354 109 MI, 12 633 AKI, and 156 057 UGIB were identified using specific definitions. The number of detectable drugs ranged from 61 for MI to 25 for ALI. Design variants generated more than 50 000 points estimates. Results by outcome will be published in forthcoming papers. CONCLUSIONS: ALCAPONE has shown the interest of the empirical assessment of pharmacoepidemiological approaches for drug safety alert generation and may encourage other researchers to do the same in other databases.