Identification and mapping of worldwide sources of generic real-world data.

PURPOSE: The demand for real-world data as supportive evidence to traditional clinical studies has increased in the past few years. The present study aimed to identify worldwide generic sources of real-world data and to assess completeness and suitability of selected real-world evidence (RWE) data sources to conduct prespecified research. METHODS: A systematic literature review was conducted to identify generic (non-disease specific) sources of real-world data in Medline and Embase from January 1, 2010 to September 8, 2015. Data sources used in observational studies were identified and summarized based on their geographical distribution and the type of data. In the next step, the selected data sources were critically evaluated for their completeness. RESULTS: A total of 10,069 identified publications were screened, leading to 2635 unique data sources across 102 countries. Europe had the maximum number of data sources (n = 1163) followed by United States (n = 578), and Asia, Middle East, and African Countries (n = 374). The most common type of identified data sources across all countries was structured data sources, ie, administrative databases and registries. Of the identified data sources, 300 were selected for further investigation. From the selected databases, ~50% had confirmed information on over 60% of the investigated variables, ~61% were suitable for epidemiological research, and 60% had possibility of linkage. CONCLUSIONS: The present study applied a systematic literature review approach and identified available generic sources of real-world data worldwide, in addition to the United States and Europe, which are suitable for conducting pre-defined researches and support future RWE studies.

Does the route of administration for estrogen hormone therapy impact the risk of venous thromboembolism? Estradiol transdermal system versus oral estrogen-only hormone therapy.

OBJECTIVE: The aim of this study was to quantify the magnitude of risk reduction for venous thromboembolism events associated with an estradiol transdermal system relative to oral estrogen-only hormone therapy agents. METHODS: A claims analysis was conducted using the Thomson Reuters MarketScan database from January 2002 to October 2009. Participants 35 years or older who were newly using an estradiol transdermal system or an oral estrogen-only hormone therapy with two or more dispensings were analyzed. Venous thromboembolism was defined as one or more diagnosis codes for deep vein thrombosis or pulmonary embolism. Cohorts of estradiol transdermal system and oral estrogen-only hormone therapy were matched 1:1 based on both exact factor and propensity score matching, and an incidence rate ratio was used to compare the rates of venous thromboembolism between the matched cohorts. Remaining baseline imbalances from matching were included as covariates in multivariate adjustments. RESULTS: Among the matched estradiol transdermal system and oral estrogen-only hormone therapy users (27,018 women in each group), the mean age of the cohorts was 48.9 years; in each cohort, 6,044 (22.4%) and 1,788 (6.6%) participants had a hysterectomy and an oophorectomy at baseline, respectively. A total of 115 estradiol transdermal system users developed venous thromboembolism, compared with 164 women in the estrogen-only hormone therapy cohort (unadjusted incidence rate ratio, 0.72; 95% CI, 0.57-0.91; P = 0.006). After adjustment for confounding factors, the incidence of venous thromboembolism remained significantly lower for estradiol transdermal system users than for estrogen-only hormone therapy users. CONCLUSIONS: This large population-based study suggests that participants receiving an estradiol transdermal system have a significantly lower incidence of venous thromboembolism than do participants receiving oral estrogen-only hormone therapy.

Systemic Medication Associations with Presumed Advanced or Uncontrolled Primary Open-Angle Glaucoma.

PURPOSE: To identify associations between systemic medications and primary open-angle glaucoma (POAG) requiring a procedure using United States insurance claims data in a hypothesis-generating study. DESIGN: Database study. PARTICIPANTS: In total, 6130 POAG cases (defined as patients with POAG undergoing a glaucoma procedure) were matched to 30 650 controls (defined as patients undergoing cataract surgery but without a coded glaucoma diagnosis, procedure, or medication) by age, gender, and region of residence. METHODS: Participant prescription drug use was calculated for the 5-year period before the glaucoma procedure or cataract surgery. Separately for individual generic drugs and drug classes, logistic regression was used to assess the association with POAG status. This was done across all generic drugs and drug classes that were prescribed in at least 1% of cases and controls. Analyses were adjusted for age, sex, region of residence, employment status, insurance plan type, and the total number of drugs prescribed. MAIN OUTCOME MEASURES: Odds ratio (OR) and 95% confidence intervals (CIs) for the association between each drug or drug class and POAG. RESULTS: The median age of participants was 72 years, and 52% were women. We tested for associations of POAG with 423 drug classes and 1763 generic drugs, resulting in a total of 2186 statistical tests and a Bonferroni-adjusted significance threshold of P < 2.3 × 10-5. Selective serotonin reuptake inhibitors (SSRIs) were strongly associated with a reduced risk of POAG (OR, 0.70; 95% CI, 0.64-0.76; P = 1.0 × 10-15); the most significant drug in this class was citalopram (OR, 0.66; 95% CI, 0.57-0.77; P = 1.2 × 10-7). Calcium channel blockers were strongly associated with an increased risk of POAG (OR, 1.26; 95% CI, 1.18-1.35; P = 1.8 × 10-11); the most significant drug in this class was amlodipine (OR, 1.27; 95% CI, 1.18-1.37; P = 5.9 × 10-10). CONCLUSIONS: We present data documenting potential associations of SSRIs and calcium channel blockers with POAG requiring a procedure. Further research may be indicated to better evaluate any associates of serotonin metabolism or calcium channels in glaucoma, or establish whether the associations are due to variations in the patterns for prescribing these drugs.

Evaluation of Healthcare Interventions and Big Data: Review of Associated Data Issues.

Although the analysis of 'big data' holds tremendous potential to improve patient care, there remain significant challenges before it can be realized. Accuracy and completeness of data, linkage of disparate data sources, and access to data are areas that require particular focus. This article discusses these areas and shares strategies to promote progress. Improvement in clinical coding, innovative matching methodologies, and investment in data standardization are potential solutions to data validation and linkage problems. Challenges to data access still require significant attention with data ownership, security needs, and costs representing significant barriers to access.

Venous thromboembolism and cardiovascular disease complications in menopausal women using transdermal versus oral estrogen therapy.

OBJECTIVE: To evaluate the risk of venous thromboembolism (VTE) and cardiovascular disease (CVD) complications, and assess healthcare costs in menopausal women using an estradiol transdermal system versus oral estrogen therapy (ET). METHODS: Health insurance claims from 60 self-insured US companies from 1999 to 2011 were analyzed. Women at least 50 years of age, newly initiated on transdermal or oral ET, were included. Cohorts were matched 1:1 based on exact factors and propensity score-matching methods. The incidence rate ratios (IRRs) of CVD complications, as well as VTE and other CVD events separately, were assessed through conditional Poisson models. Cohorts were also compared for healthcare costs using linear regression models to assess per-patient per-month cost differences. Confidence intervals (CIs) and P values were determined using a nonparametric method for cost outcomes. RESULTS: From each cohort, 2,551 users were matched to form the study population. A total of 274 transdermal ET users developed CVD complications compared with 316 women in the oral ET cohort (adjusted IRR 0.81; 95% CI, 0.67-0.99). Transdermal ET users also incurred lower adjusted all-cause and VTE/CVD-related healthcare costs relative to oral ET users (all-cause per-patient per-month cost difference [95% CI] = $41 [-34; 137], P = 0.342). CONCLUSIONS: This large matched-cohort study based on real-world data suggests that women receiving transdermal ET have significantly lower incidences of CVD events compared with those receiving oral ET, and that they also incur lower healthcare costs.

Comparison of Benefit-Risk Assessment Methods for Prospective Monitoring of Newly Marketed Drugs: A Simulation Study.

OBJECTIVES: To compare benefit-risk assessment (BRA) methods for determining whether and when sufficient evidence exists to indicate that one drug is favorable over another in prospective monitoring. METHODS: We simulated prospective monitoring of a new drug (A) versus an alternative drug (B) with respect to two beneficial and three harmful outcomes. We generated data for 1000 iterations of six scenarios and applied four BRA metrics: number needed to treat and number needed to harm (NNT|NNH), incremental net benefit (INB) with maximum acceptable risk, INB with relative-value-adjusted life-years, and INB with quality-adjusted life-years. We determined the proportion of iterations in which the 99% confidence interval for each metric included and excluded the null and we calculated mean time to alerting. RESULTS: With no true difference in any outcome between drugs A and B, the proportion of iterations including the null was lowest for INB with relative-value-adjusted life-years (64%) and highest for INB with quality-adjusted life-years (76%). When drug A was more effective and the drugs were equally safe, all metrics indicated net favorability of A in more than 70% of the iterations. When drug A was safer than drug B, NNT|NNH had the highest proportion of iterations indicating net favorability of drug A (65%). Mean time to alerting was similar among methods across the six scenarios. CONCLUSIONS: BRA metrics can be useful for identifying net favorability when applied to prospective monitoring of a new drug versus an alternative drug. INB-based approaches similarly outperform unweighted NNT|NNH approaches. Time to alerting was similar across approaches.

Prospective Benefit-Risk Monitoring of New Drugs for Rapid Assessment of Net Favorability in Electronic Health Care Data.

BACKGROUND: Benefit-risk assessment (BRA) methods can combine measures of benefits and risks into a single value. OBJECTIVES: To examine BRA metrics for prospective monitoring of new drugs in electronic health care data. METHODS: Using two electronic health care databases, we emulated prospective monitoring of three drugs (rofecoxib vs. nonselective nonsteroidal anti-inflammatory drugs, prasugrel vs. clopidogrel, and denosumab vs. bisphosphonates) using a sequential propensity score-matched cohort design. We applied four BRA metrics: number needed to treat and number needed to harm; incremental net benefit (INB) with maximum acceptable risk; INB with relative-value-adjusted life-years; and INB with quality-adjusted life-years (QALYs). We determined whether and when the bootstrapped 99% confidence interval (CI) for each metric excluded zero, indicating net favorability of one drug over the other. RESULTS: For rofecoxib, all four metrics yielded a negative value, suggesting net favorability of nonselective nonsteroidal anti-inflammatory drugs over rofecoxib, and the 99% CI for all but the number needed to treat and number needed to harm excluded the null during follow-up. For prasugrel, only the 99% CI for INB-QALY excluded the null, but trends in values over time were similar across the four metrics, suggesting overall net favorability of prasugrel versus clopidogrel. The 99% CI for INB-relative-value-adjusted life-years and INB-QALY excluded the null in the denosumab example, suggesting net favorability of denosumab over bisphosphonates. CONCLUSIONS: Prospective benefit-risk monitoring can be used to determine net favorability of a new drug in electronic health care data. In three examples, existing BRA metrics produced qualitatively similar results but differed with respect to alert generation.

A unified framework for classification of methods for benefit-risk assessment.

BACKGROUND: Patients, physicians, and other decision makers make implicit but inevitable trade-offs among risks and benefits of treatments. Many methods have been proposed to promote transparent and rigorous benefit-risk analysis (BRA). OBJECTIVE: To propose a framework for classifying BRA methods on the basis of key factors that matter most for patients by using a common mathematical notation and compare their results using a hypothetical example. METHODS: We classified the available BRA methods into three categories: 1) unweighted metrics, which use only probabilities of benefits and risks; 2) metrics that incorporate preference weights and that account for the impact and duration of benefits and risks; and 3) metrics that incorporate weights based on decision makers' opinions. We used two hypothetical antiplatelet drugs (a and b) to compare the BRA methods within our proposed framework. RESULTS: Unweighted metrics include the number needed to treat and the number needed to harm. Metrics that incorporate preference weights include those that use maximum acceptable risk, those that use relative-value-adjusted life-years, and those that use quality-adjusted life-years. Metrics that use decision makers' weights include the multicriteria decision analysis, the benefit-less-risk analysis, Boers' 3 by 3 table, the Gail/NCI method, and the transparent uniform risk benefit overview. Most BRA methods can be derived as a special case of a generalized formula in which some are mathematically identical. Numerical comparison of methods highlights potential differences in BRA results and their interpretation. CONCLUSIONS: The proposed framework provides a unified, patient-centered approach to BRA methods classification based on the types of weights that are used across existing methods, a key differentiating feature.

Costs and health care resource utilization among chronic obstructive pulmonary disease patients with newly acquired pneumonia.

BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) are at increased risk for lung infections and other pathologies (eg, pneumonia); however, few studies have evaluated the impact of pneumonia on health care resource utilization and costs in this population. The purpose of this study was to estimate health care resource utilization and costs among COPD patients with newly acquired pneumonia compared to those without pneumonia. METHODS: A retrospective claims analysis using Truven MarketScan(®) Commercial and Medicare databases was conducted. COPD patients with and without newly acquired pneumonia diagnosed between January 1, 2004 and September 30, 2011 were identified. Propensity score matching was used to create a 1:1 matched cohort. Patient demographics, comorbidities (measured by Charlson Comorbidity Index), and medication use were evaluated before and after matching. Health care resource utilization (ie, hospitalizations, emergency room [ER] and outpatient visits), and associated health care costs were assessed during the 12-month follow-up. Logistic regression was conducted to evaluate the risk of hospitalization and ER visits, and gamma regression models and two-part models compared health care costs between groups after matching. RESULTS: In the baseline cohort (N=467,578), patients with newly acquired pneumonia were older (mean age: 70 versus [vs] 63 years) and had higher Charlson Comorbidity Index scores (3.3 vs 2.6) than patients without pneumonia. After propensity score matching, the pneumonia cohort was nine times more likely to have a hospitalization (odds ratio; 95% confidence intervals [CI] =9.2; 8.9, 9.4) and four times more likely to have an ER visit (odds ratio; 95% CI =4.4; 4.3, 4.5) over the 12-month follow-up period compared to the control cohort. The estimated 12-month mean hospitalization costs ($14,353 [95% CI: $14,037-$14,690]), outpatient costs ($6,891 [95% CI: $6,706-$7,070]), and prescription drug costs ($1,104 [95% CI: $1,054-$1,142]) were higher in the pneumonia cohort than in the control cohort. CONCLUSION: This study demonstrated elevated health care resource use and costs in patients with COPD after acquiring pneumonia compared to those without pneumonia.

Group-based trajectory modeling to assess adherence to biologics among patients with psoriasis.

BACKGROUND: Proportion of days covered (PDC), a commonly used adherence metric, does not provide information about the longitudinal course of adherence to treatment over time. Group-based trajectory model (GBTM) is an alternative method that overcomes this limitation. METHODS: The statistical principles of GBTM and PDC were applied to assess adherence during a 12-month follow-up in psoriasis patients starting treatment with a biologic. The optimal GBTM model was determined on the basis of the balance between each model's Bayesian information criterion and the percentage of patients in the smallest group in each model. Variables potentially predictive of adherence were evaluated. RESULTS: In all, 3,249 patients were included in the analysis. Four GBTM adherence groups were suggested by the optimal model, and patients were categorized as demonstrating continuously high adherence, high-then-low adherence, moderate-then-low adherence, or consistently moderate adherence during follow-up. For comparison, four PDC groups were constructed: PDC Group 4 (PDC ≥75%), PDC Group 3 (25%≤ PDC <50%), PDC Group 2 (PDC <25%), and PDC Group 1 (50%≤ PDC <75%). Our findings suggest that the majority of patients (97.9%) from PDC Group 2 demonstrated moderate-then-low adherence, whereas 96.4% of patients from PDC Group 4 showed continuously high adherence. The remaining PDC-based categorizations did not capture patients with uniform adherence behavior based on GBTM. In PDC Group 3, 25.3%, 17.2%, and 57.5% of patients exhibited GBTM-defined consistently moderate adherence, moderate-then-low adherence, or high-then-low adherence, respectively. In PDC Group 1, 70.8%, 23.6%, and 5.7% of patients had consistently moderate adherence, high-then-low adherence, and continuously high adherence, respectively. Additional analyses suggested GBTM-based categorization was best predicted by patient age, sex, certain comorbidities, and particular drug use. CONCLUSION: GBTM is a more appropriate way to model dynamic behaviors and offers researchers an alternative to more traditional drug adherence measurements.

A questionnaire to assess the relevance and credibility of observational studies to inform health care decision making: an ISPOR-AMCP-NPC Good Practice Task Force report.

Evidence-based health care decisions are best informed by comparisons of all relevant interventions used to treat conditions in specific patient populations. Observational studies are being performed to help fill evidence gaps. Widespread adoption of evidence from observational studies, however, has been limited because of various factors, including the lack of consensus regarding accepted principles for their evaluation and interpretation. Two task forces were formed to develop questionnaires to assist decision makers in evaluating observational studies, with one Task Force addressing retrospective research and the other Task Force addressing prospective research. The intent was to promote a structured approach to reduce the potential for subjective interpretation of evidence and drive consistency in decision making. Separately developed questionnaires were combined into a single questionnaire consisting of 33 items. These were divided into two domains: relevance and credibility. Relevance addresses the extent to which findings, if accurate, apply to the setting of interest to the decision maker. Credibility addresses the extent to which the study findings accurately answer the study question. The questionnaire provides a guide for assessing the degree of confidence that should be placed from observational studies and promotes awareness of the subtleties involved in evaluating those.

Economic burden associated with extrapyramidal symptoms in a medicaid population with schizophrenia.

No studies have assessed the economic impact of extrapyramidal symptoms due to atypical antipsychotics in schizophrenia. To assess healthcare resource use and medical costs associated with extrapyramidal symptoms in patients with schizophrenia. A retrospective analysis of Marketscan(®) Medicaid Multi-State Database (2004-2009) was conducted. Patients with schizophrenia and newly initiated on an AAP were included. Patients with and without extrapyramidal symptoms were matched using propensity-score matching. Healthcare utilization and costs were assessed in the 12-month follow-up period using logistic and two-part (gamma) regression models. Of 4,621 patients, 583 (12.6 %) had extrapyramidal symptoms. Patients with extrapyramidal symptoms had significantly more schizophrenia-related and all-cause hospitalizations and schizophrenia-related emergency room visits, as well as significantly higher schizophrenia-specific and all-cause total healthcare, inpatient, and prescription drug costs compared to patients without extrapyramidal symptoms. Extrapyramidal symptoms in patients with schizophrenia is associated with increased healthcare resource utilization and higher medical costs.

Treatment dynamics of newly marketed drugs and implications for comparative effectiveness research.

OBJECTIVES: Clinicians and payers require rapid comparative effectiveness (CE) evidence generation to inform decisions for new drugs. We empirically assessed treatment dynamics of newly marked drugs and their implications for conducting CE research. METHODS: We used claims data to evaluate five drug-outcome pairs: 1) raloxifene (vs. alendronate) and fracture; 2) risedronate (vs. alendronate) and fracture; 3) simvastatin plus ezetimibe fixed-dose combination (simvastatin + ezetimibe) (vs. simvastatin alone) and cardiovascular events; 4) rofecoxib (vs. nonselective nonsteroidal anti-inflammatory drugs [ns-NSAIDs]) and myocardial infarction; and 5) rofecoxib (vs. ns-NSAIDS) and gastrointestinal bleed. We examined utilization dynamics in the early marketing period, including evolving utilization patterns, outcome risk among those treated with new versus established drugs, and prior treatment patterns that may indicate treatment resistance or intolerance. We addressed these challenges by replicating active CE monitoring with sequential matched cohort analysis. RESULTS: Patients initiating new drugs were more likely to have used other drugs for the same indication in the past, but the majority of patients in all new drug cohorts were treatment naive (82.0% overall). Patients initiating rofecoxib had higher predicted baseline risk of gastrointestinal bleed than did patients initiating ns-NSAIDs. Patients initiating risedronate and alendronate had similar predicted baseline risks of fracture, while those initiating raloxifene and simvastatin + ezetimibe had lower risks of outcomes of interest relative to their comparators. Prospective monitoring yielded results consistent with expectation for each example. CONCLUSIONS: Many challenges to assessing the CE of new drugs are borne out in empirical data. Attention to these challenges can yield valid CE results.

Inhaled corticosteroid use in patients with chronic obstructive pulmonary disease and the risk of pneumonia: a retrospective claims data analysis.

BACKGROUND: The use of inhaled corticosteroids in patients with chronic obstructive pulmonary disease (COPD) has been associated with an increased risk of pneumonia in controlled clinical trials and case-control analyses. OBJECTIVE: Using claims databases as a research model of real-world diagnosis and treatment, to determine if the use and dose of inhaled corticosteroids (ICS) among patients with newly diagnosed COPD are associated with increased risk of pneumonia. PATIENTS AND METHODS: This was a retrospective cohort analysis of patients diagnosed with COPD between January 01, 2006 and September 30, 2010, drawn from databases (years 2006-2010). Patients (aged ≥45 years) were followed until first pneumonia diagnosis, end of benefit enrollment, or December 31, 2010, whichever was earliest. A Cox proportional hazard model was used to assess the association of ICS use and risk of pneumonia, controlling for baseline characteristics. Daily ICS use was classified into low, medium, and high doses (1 µg-499 µg, 500 µg-999 µg, and ≥1000 µg fluticasone equivalents daily) and was modeled as a time-dependent variable. RESULTS: Among 135,445 qualifying patients with a total of 243,097 person-years, there were 1020 pneumonia incidences out of 5677 person-years on ICS (crude incidence rate, 0.180 per person-year), and 27,730 pneumonia incidences out of 237,420 person-years not on ICS (crude incidence rate, 0.117 per person-year). ICS use was associated with a dose-related increase in risk of pneumonia, with adjusted hazard ratios (versus no use; (95% confidence interval) of 1.38 (1.27-1.49) for low-dose users, 1.69 (1.52-1.88) for medium-dose users, and 2.57 (1.98-3.33) for high-dose users (P < 0.01 versus no use and between doses). CONCLUSION: The use of ICS in newly diagnosed patients with COPD is potentially associated with a dose-related increase in the risk of pneumonia.

Resource utilization, costs and treatment patterns of switching and discontinuing treatment of MS patients with high relapse activity.

BACKGROUND: Multiple sclerosis (MS) is a chronic disease that affects mainly adults in the prime of their lives. However, few studies report the impact of high annual relapse rates on outcomes. The purpose of this study was to identify high relapse activity (HRA) in patients with MS, comparing differences in outcomes between patients with and without HRA. METHODS: A retrospective longitudinal study was conducted using the MarketScan® Commercial Claims and Encounters and Medicare Supplemental Database. Patients had to have at least one ICD-9 for MS (340.XX) in 2009 and one in 2008, be older than 18 years, and have continuous enrolment in the years 2009-2010. HRA was defined as having ≥2 relapses in 2009. Multivariate analyses compared all-cause and MS-specific emergency room (ER) visits, hospitalizations, and all-cause costs, excluding disease modifying therapy (DMT) costs, in 2010 between patients with and without HRA, controlling for baseline characteristics. A subgroup analysis using treatment exposure was also performed. RESULTS: 19,219 patients were included: 5.3% (n=1,017) had ≥2 relapses in 2009. Patients with HRA were more likely to have all-cause and MS-specific resource utilization than patients without HRA. Mean total all-cause non DMT costs were $12,057 higher for the HRA group. In the subgroup analysis, HRA treatment-naïve patients were more likely to start treatment, and HRA treatment-experienced patients were more likely to discontinue or switch index DMT (P<0.01). CONCLUSIONS: Patients with ≥2 relapses annually have higher resource utilization and costs. The difference in cost was over twice as large in treatment-naïve patients versus treatment-experienced patients. HRA was also associated with an increased likelihood of starting DMT treatment (treatment-naïve patients), and switching or discontinuing DMT therapy (treatment-experienced patients).

Health care utilization and costs among patients with AD with and without dysphagia.

OBJECTIVE: To assess health care utilization and associated costs among patients with Alzheimer disease (AD), with and without dysphagia. METHODS: MarketScan Commercial and Medicare databases were analyzed. Patients with a diagnosis of AD with and without dysphagia between October 2006 and September 2010 were included. Acetylcholinesterase inhibitor usage, the number of outpatient and emergency room (ER) visits and hospitalizations, and associated health care costs were assessed. All variables were measured 1 year after the initial diagnosis of AD at the patient level. Patients with dysphagia were matched to patients without dysphagia using propensity score-matching (PSM) methods. Regression models were conducted to compare utilization and costs between the 2 groups. RESULTS: A total of 485 patients with dysphagia and 8492 patients without dysphagia were included. Before matching, patients with dysphagia were older (81.1 vs. 79.8 y), and had higher Charlson Comorbidity Index scores (2.4 vs. 1.7). After matching, all baseline covariates were not statistically different between the 2 groups. Multivariate regression results showed that patients with dysphagia had a higher likelihood of all-cause hospitalizations [odds ratio (OR)=2.26, 95% confidence interval (CI)=1.70-2.99, P=0.001] and all-cause ER visits (OR=1.45, 95% CI=1.12-1.87, P=0.007) compared with patients without dysphagia; they also had a higher likelihood for AD-related hospitalizations and ER visits. The difference in all-cause total health care, ER, and hospitalization costs between patients with and without dysphagia were $3620 (95% CI=$2863-$4375), $258 (95% CI=$241-$274), and $3547 (95% CI=$3325-$3770), respectively. CONCLUSIONS: This study suggests that patients with AD and dysphagia have higher health care utilization and costs compared with patients without dysphagia.

Patient adherence to transdermal rivastigmine after switching from oral donepezil: a retrospective claims database study.

OBJECTIVE: To examine patient adherence before and after switching from donepezil to the rivastigmine patch. METHODS: This retrospective cohort study used the MarketScan Commercial and Medicare data sets (2004 to 2009). Patients with a diagnosis of Alzheimer disease who were new donepezil users and were subsequently switched to the rivastigmine patch were included. The proportion of days covered (PDC) and PDC difference between donepezil and the rivastigmine patch were calculated from the time of initiation to the switch, capped at 1 year after the first respective claim. PDC was calculated as the number of days with drugs available divided by the number of days in the respective follow-up periods. RESULTS: The sample included 772 patients (mean age 77 y; 58% female). The mean time between switching from donepezil to the rivastigmine patch was 579 (SD=317.3) days. The mean PDC for the rivastigmine patch was highest among patients who switched within 3 months (80.4% vs. 90.7%; P=0.04) and within 7 to 9 months (61.3% vs. 71.0%; P=0.05) of initiating donepezil. When adherence was analyzed in increments of 1 year, patients who switched to the rivastigmine patch within the first year of treatment had significantly greater adherence to rivastigmine compared with those who were on donepezil (PDC 69.3% vs. 60.6%; P=0.0004). CONCLUSIONS: Switching from donepezil to the rivastigmine patch seems to be associated with increased adherence, especially in patients who switched within the first year of initiating donepezil.