1,721,064 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Does Cost-Effectiveness Analysis Have a Role in US Managed Care Drug Formularies? An Empirical Study of Utilization, Costs, Outcomes, and Elasticity of Demand of a Value-Based Formulary
Full text linkThesis (Ph.D.)--University of Washington, 2015The standard economic model for health insurance posits that in order to account for moral hazard in a population for which there is varying marginal benefit of treatment that is unknown to the insurer, cost-sharing should be proportional to the price elasticity of demand. Yet, many have observed that when faced with cost-sharing, consumers may reduce utilization to suboptimal levels due to underestimation of the marginal benefit of treatment. Hence, optimal health insurance design requires consideration of both insurer and consumer information asymmetries regarding the marginal benefits of treatment. This dissertation investigates whether cost-effectiveness analysis (CEA) may be useful for optimizing insurance in the face of insurer and consumer information asymmetries. In 2010, Premera Blue Cross, a large non-profit health plan in the Pacific Northwest implemented a value based formulary (VBF) benefit among their own employees and dependents that explicitly uses CEA to inform medication placement within copayment tiers. We exploit this natural experiment to empirically assess the impact of the VBF on medication utilization and other health services utilization and the impact of the VBF on medication costs and non-medication costs from the member, health plan, and overall perspectives. We also estimate price elasticities of demand for pharmaceuticals overall, by therapeutic class, by brand-generic status, and finally by the copayment tiers informed by CEA. In the first paper, we use individual-level data from July 2006 to June 2013 drawn from the employees of Premera and their dependents as well as data from employees and dependents of 5 employer sponsored plans administrated by Premera and chosen based on similarity to the intervention group in industry classification. After controlling for member demographics and plan characteristics and secular trends using an interrupted time series design with concurrent control, we find that the VBF shifted member medication utilization towards drugs placed in lower copayment tiers. The VBF also was associated with increased member medication costs and decreased health plan medication costs, leading to a net medication savings of 15, -1.1 million USD. The findings regarding non-medication costs were comparatively small and not statistically significant. Total costs decreased by 49, $30) but was not statistically significant. We did not detect any changes in the probability or the number of emergency department visits, hospitalizations, or office visits. This evaluation suggests that the VBF may have reduced overall medication costs without negatively impacting utilization of other health services – a proxy for adverse outcomes. In the second paper, we use data from July 2009 to June 2011 drawn from the employees of Premera and their dependents to construct a medication level dataset of 284 unique medications. These medications accounted for 79.3% of the prescription medication volume over the period of observation. After controlling for member demographics and using a pre-post design, we find that our elasticity estimates of -0.14 for the probability of filling a medication were similar to the overall elasticity estimates of -0.17 from the RAND Health Insurance Experiment. We also find that the estimates by therapeutic class and brand-generic status also were generally similar to published studies. Finally, we estimate of price elasticity of demand by copayment tiers informed by CEA. We found that elasticity estimates for the probability of fill and days’ supply of medication respectively were -0.07 and -0.06 for the preventive tier, -0.09 and 0.08 for tier 1, -0.26 and -0.26 for tier 2, -0.27 and -0.32 for tier 3, and -0.45 and -0.55 for tier 4. Thus we observed a general trend of increasing elasticity with increasing copayment tiers. These results suggest that a cost sharing strategy based on elasticity estimates may be similar to a cost sharing strategy informed by CEA. Furthermore, since in the first paper we observed that the VBF was associated with decreased medication costs without negatively impacting health services utilization, we suggest that the use of CEA to inform medication copayment tiers may have a role in optimizing insurance benefit design. Contemporaneous with the implementation of the VBF on July 2010, the US health insurance market has experienced many changes. The passage of the Patient Protection and Affordable Care Act (PPACA) in March 2010 and the progressive implementation of many provisions in that law have fundamentally altered the insurance and provider markets. One provision in PPACA explicitly supports the development of value-based insurance design. This provision has led to the promulgation of federal regulations that have focused on eliminating cost-sharing for certain preventive services. The PPACA also has mandated coverage of preventive services recommended by Advisory Committee on Immunization Practices and the US Preventive Services Task Force. Due to the direct influence these national advisory bodies now have on the coverage of preventive services, others have advocated use of CEA by these bodies to inform the relative costs and benefits of their decisions. Our research suggests that the application of CEA to explicitly inform cost-sharing may allow the expansion of value-based principles beyond waivers of cost-sharing for specific “high value” services. Another important provision of PPACA is the formation of Accountable Care Organizations (ACOs) by health care providers that are accountable for the quality, cost, and overall care of Medicare beneficiaries. Under this provision, the ACOs enter into payment contracts that share both financial risk and savings for the care of beneficiaries. This shift in financial risk may cause ACOs to become more aware of the cost of health care. Further, since providers can greatly influence medications utilization behavior, ACOs may become an important lever for the introduction of value-based principles in integrated delivery system models. Finally, PPACA and the Health Information Technology for Economic and Clinical Health Act of 2009 have financially incentivized the use of electronic health records (EHR). It is possible that future iterations of VBFs could utilize patient-level information from EHRs to more accurately triangulate levels of cost-sharing with better estimates of treatment benefit. Further, the adoption of electronic health records may allow for future evaluations of VBFs that are able to assess true health outcomes. In sum, changes in the health insurance market present many opportunities and challenges for the adoption and evaluation of value-based principles in health insurance design. Policymakers and researchers should carefully assess such dynamics when considering the role of value-based insurance in health insurance markets in the future. Footnote: A joint regulation issued by the Department of Health and Human Services, the Internal Revenue Service and the Department of Labor, regarding the elimination copayments for certain preventive services states “The Departments recognize the important role that value-based insurance design can play in promoting the use of appropriate preventive services.
The impact of adherence and an intervention program on patient outcomes and costs in chronic hepatitis C infection
No full textThesis (Master's)--University of Washington, 2012Background and aims: Both observational studies and randomized trials have shown that higher medication adherence is associated with improved outcomes in patients with chronic hepatitis C infection (CHC). Little evidence exists on the association between adherence and health care costs. We sought to evaluate the impact of adherence on long-term outcomes and costs in a population of patients with CHC genotype 1 receiving peginterferon and ribavirin (PEG-RBV). We also evaluated the impact of a potential intervention to improve adherence on long-term costs and patient outcomes. Methods: We utilized a cohort Markov model describing the natural history of hepatitis C infection in a population of 50 year-old treatment-experienced adults to evaluate the following health states: CHC, compensated cirrhosis, decompensated cirrhosis, hepatocellular carcinoma, liver transplant, liver transplant survivor, and death. Using previously published data from the HALT-C trial, we modeled four levels of medication receipt: >80% PEG-RBV, >80% PEG/Results: Over a lifetime horizon, we compared patients with the highest adherence versus lowest adherence, and found the following reductions in liver-related events: 9.9% compensated cirrhosis, 4.7% decompensated cirrhosis, 1.4% hepatocellular carcinoma, and 0.5% liver transplant. The potential cost savings over a lifetime as patients move from a cohort of lower SVR to greater SVR ranged from 62,690, with a 1% increase in SVR associated with savings of 3284. Conclusion: Interventions that increase patient adherence should improve outcomes in this population and have the potential to reduce costs
Antiepileptic Drug Switching and Epilepsy-related Events in Subjects with Epilepsy: A Case-Control Analysis of Health Insurance Claims Data
No full textThesis (Master's)--University of Washington, 2013Background: Epilepsy is frequently debilitating and switching between bioequivalent antiepileptic drugs (AEDs) with narrow therapeutic index remains controversial. Methods: We investigated the association between A-rated switching and emergent treatment for an epilepsy-related event over a 1-year period using recent claims data from the Truven Health MarketScan® Commercial Database. Cases and matched controls with a diagnosis of epilepsy were identified using emergency services and inpatient visits or outpatient visit claims, respectively. Cases and controls were matched using a 1:1 ratio for age within 5 years of the case's age and seizure diagnosis category. The exposure was defined as an A-rated switch of an AED during the 90 days prior to index date. Adjusted analyses controlled for matching, sex, AED type (older vs. newer AEDs), Deyo-Charlson comorbidity index score, and total number of AED prescription filled. Results: 1,873 of 7,843 (24%) cases and 1,566 matched controls (20%) experienced an A-rated switch. The unadjusted odds of an epilepsy-related event were 1.26 for switchers (95% CI: 1.17-1.36), and after controlling for all confounders, 1.15 (95% CI: 1.06-1.25). Compared with other AEDs, switching of carbamazepine and phenytoin is associated with increased risk of epilepsy-related events. Discussion: Individuals with epilepsy who switch between A-rated formulations of AEDs are more likely to experience an emergently treated epilepsy-related event compared with individuals who do not switch. Compared with newer AEDs, switching of some older AEDs such as carbamazepine and phenytoin is associated with increased risk of epilepsy-related events. Effective management of epilepsy requires clinicians, pharmacists, and patients to understand the factors associated with bioequivalent medication substitutions. Physicians and pharmacists should actively seek to prevent switching of anti-epileptic medications once patients are stabilized on a specific product - whether branded or generic version. Such switching increases the odds of an epileptic event
The impact of depression on patient outcomes among older adults with lung cancer
Full text linkThesis (Ph.D.)--University of Washington, 2016-06Background: Depression is a common malady among older adults, and as the incidence of cancer increases with age, older adults may be living with both cancer and depression. Previous studies have assessed the impact of depression on patient outcomes when depression is measured around the time of a cancer diagnosis or during cancer treatment, but we know very little about how depression preceding the cancer diagnosis affects patient outcomes during the course of cancer treatment. Using the example of lung cancer, the most common cause of cancer death among older adults, we examined the association between pre-existing depression and cancer stage at diagnosis, survival, and health care utilization. Methods: We used the national Surveillance, Epidemiology, and End Results (SEER) database, linked to Medicare healthcare and prescription claims, to examine the association between pre-existing depression and patient outcomes for older adults with non-small cell lung cancer (NSCLC) diagnosed between 2008-2011 with claims from 2007-2013. We used multivariate logistic regression models to investigate the association of pre-existing depression, advanced NSCLC stage at diagnosis, and receipt of aggressive end-of-life care. We estimated multivariate Cox proportional hazards models to examine the association of pre-existing depression and overall survival. We utilized competing risk regression models to examine the relationship between pre-existing depression and time to anticancer therapy or hospice enrollment. Results: We included 24,666 people in our analysis. Older adults with pre-existing depression were less likely to be diagnosed with advanced stage NSCLC (OR 0.76, 95% CI 0.68-0.85). Of the 8,873 older adults with stages 1-3A NSCLC, persons with pre-existing depression and stage 1 NSCLC had a higher risk of death compared to those without depression (OR 1.19, 95% CI 1.01-1.41). We found similar patterns of anticancer therapy receipt between older adults with or without pre-existing depression, and no significant difference in time to first anticancer treatment, accounting for the competing risk of death. Among 14,385 decedents with stage 3B or 4 NSCLC, those with pre-existing depression were more likely to enroll in hospice than persons without depression (SHR 1.16, 95% CI 1.06-1.28). We found no difference in utilization of inpatient hospitalizations, emergency room use, or chemotherapy receipt in the last 30 days of life, comparing those with versus those without pre-existing depression. Discussion: In a national sample of older adults with NSCLC, pre-existing depression was associated with earlier stage at cancer diagnosis, shorter survival among those with early stage NSCLC and higher hospice utilization among persons with advanced NSCLC. These findings indicate the importance of screening for and treating depression during cancer therapy. As people with pre-existing depression are more likely to enroll in hospice, it is important that hospice organizations and caregivers have sufficient support to address cancer and mental health concerns at end-of-life
Bariatric Surgery for Severe Obesity: Determinants of Use and Economic Impact
No full textThesis (Ph.D.)--University of Washington, 2013Objectives: Obesity in the U.S. population is a major public health problem with important clinical and economic implications. Bariatric surgery is currently the most effective long-term weight loss treatment for morbid obesity but less than 2% of the potentially eligible population has undergone the procedure. Our aims were to: 1) determine the patient characteristics associated with receiving a bariatric procedure among eligible patients; 2) identify patient characteristics that could be used as predictors of resource use and costs in severely obese patients with and without bariatric surgery; and 3) estimate and project the differences in long-term costs and outcomes across different clinically defined populations undergoing bariatric surgery compared to non-surgical approaches, refining a previously developed cost-effectiveness model. Methods: We used electronic medical records from members of Group Health Cooperative, based in Washington State to identify severely obese individuals, eligible for bariatric surgery, from 2004 to 2010. The probability of undergoing bariatric surgery was assessed using multivariate logistic regression adjusting for demographic and clinical characteristics, as well as patterns of practice. To determine the predictors of costs, we used generalized linear models for both groups with similar adjustment variables. We created a propensity score matched cohort based on specific characteristics previously identified at the date of surgery and the assigned index date for those who did not have surgery. Finally, we used these data to update a previously developed cost-effectiveness model to re-estimate the cost-effectiveness of bariatric surgery compared to non-surgical interventions. Results: A total of 48,166 subjects were identified as eligible for bariatric surgery. Only 1,129 had bariatric surgery. The characteristics associated with having a bariatric procedure were: having insurance coverage for the procedure (OR=5.61; 4.71-6.68), higher body mass index (BMI) (1.10; 1.09-1.11), and older age (1.00; 1.00-1.01). The presence of comorbidities was associated with higher odds of having surgery. Examining comorbidities individually, only coronary heart disease was not associated with the surgery (0.96; 0.74-1.26). These characteristics changed over time, showing time trends towards increasing numbers of older adults and subjects with lower BMI having the procedure in the recent years. For costs, total annual costs were higher prior to surgery in the bariatric surgery group but decreased more (in absolute and relative terms) after the surgery compared to the non-surgical group. The total health care costs post-surgery for both groups were primarily driven by inpatient costs. The presence of comorbid conditions was associated with greater annual total costs in both groups. Major cardiovascular risk factors, such as coronary heart disease, hypertension, diabetes, and a higher comorbidity index, were associated with the highest increase in mean annual total costs. Despite being more expensive, bariatric surgery is cost-effective due to the impact on weight loss, which is associated with improved life expectancy and quality of life after the procedure. The incremental cost-effectiveness ratio of the bariatric surgery is sensitive to the presence of multiple comorbidities, mainly due to the reduction in the differences in the lifetime costs between surgical and non-surgical interventions for patients with multiple comorbidities. Conclusions: There are demographic, clinical, and insurance differences among subjects eligible for bariatric surgery that receive and do not receive the surgery. The presence of specific comorbid conditions increases the probability of surgery and is associated with higher total costs in this population. The cost-effectiveness of these procedures also depends on the presence of specific comorbid conditions. Understanding these differences could better inform the decisions that patients, clinicians, payers and policy-makers face in addressing the problem of increasing population obesity
Biosimilars in the United States: Market Dynamics and Patient Out-of-Pocket Costs
Full text linkThesis (Ph.D.)--University of Washington, 2025BackgroundThe United States biosimilars market is growing rapidly and has led to significant savings for the health care system and payers. However, market complexities, barriers to entry, and fewer biosimilars in the pipeline than expected has led to concerns about the long-term sustainability of the biosimilars market and therefore threatened savings. We characterized eight physician-administered biologics markets in terms of price declines and reference product market share to better understand the heterogeneity between these markets. We also estimated the effect of biosimilar competition on patient out-of-pocket costs for rheumatology biologics, to understand whether biosimilar competition is truly resulting in savings for patients. MethodsFor Aim 1, quarterly average sales price (ASP) data from the Centers for Medicare and Medicaid Services (CMS) Drug Pricing Files along with volume data from the standard Medicare Limited Data Set (5% sample) for Medicare and the MerativeTM MarketScan® Commercial Database for the commercial population were used as data sources, using price and volume (number of claims) for the following biologics: filgrastim, rituximab, infliximab, trastuzumab, pegfilgrastim, epoetin alfa, bevacizumab, and ranibizumab. We first characterized the markets descriptively, then used linear regression to assess the relationship between reference product market share and each biosimilar entry and to study biosimilar versus reference product price decline over time since biosimilar entry. For Aim 2, the MerativeTM MarketScan® Commercial Database was used to conduct an analysis of patient OOP costs before and after biosimilar competition using the methodology described by Callaway & Sant’Anna. We included infliximab, rituximab, and adalimumab as the drug groups of interest, as they are the rheumatology biologics with biosimilars available. The exposure was biosimilar competition and the outcome was biologic-related OOP costs. ResultsIn Medicare, reference product market share declined consistently, though to varying degrees across molecule groups. In the commercial sector, market share trends were more variable, with some reference product markets remaining stable and others declining steeply. Price trends also differed substantially between payer sectors. In Medicare, biosimilars showed an 18.6% (p<0.01) greater price decline on average than reference products, while in commercial markets the overall result was not significant. Price decline patterns varied widely between the different biologics. For patient out-of-pocket costs, we observed statistically significant savings due to biosimilar competition, with an average savings of over $1,000 in the infliximab and rituximab groups over the study period. When assessing treatment effect by duration of exposure, we observed increasing savings over time, the longer biosimilars were available. In the adalimumab group, there was an increase in patient OOP costs in the year prior to biosimilar availability, which may reflect anticipatory price increases on the part of the reference manufacturer. There was minimal savings in the adalimumab group upon biosimilar entry, and no savings when accounting for one year of anticipation. ConclusionThe first study provides evidence of the differences between biologic markets in both market share and price decline trends, and the challenge of generalizing predictions or drawing generalizable conclusions about biosimilar market behavior. The second study indicates that the availability of infliximab and rituximab biosimilars led to significant savings for patients in addition to the health care system as a whole, with more savings the longer biosimilars are on the market. Together, these studies highlight the importance of policies that incentivize development of biosimilars and support the long-term availability of biosimilars to preserve and increase savings for patients
Implications and Investigations of Pharmacy Benefit in the United States
No full textThesis (Ph.D.)--University of Washington, 2012Medicaid clients are among the most at-risk members for poor health outcomes in society and this safety net health care is critical for assuring continuous access to medical care. We will describe the importance of curtailing unnecessary drug spend as well as generic utilization mechanisms already applied by payers. We will describe the background, implementation, and early findings of a prescriber feedback report card program to improve generic utilization in the Washington State Medicaid system. We quantified the association between possession of prescription drug coverage and likelihood of experiencing an emergency room [ER] visit and hospitalization in the adult United States population with private health insurance. For the outcomes of ER visits and hospitalizations, the ORs were 1.05 (95% confidence interval [CI], 0.95 to 1.15) and 1.07 (95% CI, 0.95-1.22) respectively using propensity score matching. Indicating a non-significant increase in odds of the outcomes of ER visit and hospitalization for patients possessing drug coverage . Multiple logistic regression produced similar findings. For the outcomes of ER visit and hospitalization, the adjusted ORs were 1.03 (0.96-1.12) and 1.01 (0.91-1.21) respectively. Prescription drug coverage in the United States was not associated with a reduction in likelihood of ER visit or hospitalization in this assessment pooling ten years of cross-sectional data. To estimate the reduction in adherence and medication supplied for patients that experience increases in average monthly copay over time for three therapeutically distinct drugs for chronic syndrome management using a nationally representative Commercial Claims databaseIncrease in 10 or more for average monthly copay was associated with a statistically significant reduction in MPR for all three drugs. Measured by generalized estimating equations, change in MPR varied from a minimum loss of 0.024 for simvastatin with a 10 or more increase. This equates to a minimum loss of days supply 8.8 to 23.0 for simvastatin and insulin glargine respectively. Copay increases are associated with significant reductions in adherence of chronic medications necessary for optimal disease control
Cost-Effectiveness of Delaying Alzheimer’s Disease Progression with Novel Monoclonal Antibodies
No full textThesis (Master's)--University of Washington, 2025Background: In the US alone, most of over 7.2 million older adults with Alzheimer’s Disease (AD) treat their AD with symptom-relieving therapies. Starting in 2021, three disease-modifying monoclonal antibodies (mAbs) entered the US market as the first disease-modifying treatments for early Alzheimer's disease (AD). Despite years of presence in the US market, the value of these mAbs remains uncertain due to high treatment-related costs and an unclear comparative value of their clinical benefit. Objectives: 1) To estimate the cost-effectiveness of adding aducanumab, lecanemab, or donanemab to the current standard of care (SOC) and 2) to evaluate the value of reducing uncertainties around the mAbs from a US health care perspective and a modified societal perspective.
Methods: A Markov simulation model was developed by incorporating literature and a prior cost-impact model of delaying AD progression. The clinical benefit and cohort’s characteristics mirrored results from phase 3 clinical trials of the three agents. The price of the agents was estimated using wholesale acquisition costs published by Micromedex RED BOOK. The model used a 1-week cycle length and estimated 10-year cost impact and comparative incremental cost-effectiveness ratios (ICERs) among the SOC and the mAbs. Results were described from both a health care sector and a societal perspective. One-way sensitivity analysis was conducted to demonstrate key drivers of cost-effectiveness of the mAbs. Cost-effectiveness acceptability curve and the expected value of perfect information (EVPI) used probabilistic sensitivity analysis to demonstrate the comparative value of the mAbs and the value of resolving uncertainties.
Results: The three agents were estimated to delay progression from MCI to severe AD by 6.2 - 9.2 months. The analysis showed that SOC costs 757,800 from the health care sector and the modified societal perspective, respectively, over 10 years. From the health care sector perspective, the mAbs incurred additional 73K, and 73K, and aducanumab and lecanemab added 64K to the cumulative costs, respectively. Donanemab had the higher comparative ICER at 175,300/QALY. Key driving factors of ICER among lecanemab and donanemab were age at the treatment initiation, patient health state utility values in earlier AD states, and the drug acquisition costs across both perspectives. SOC had more favorable cost-effectiveness at a WTP of 200K/QALY. The EVPI of the decisions around lecanemab versus SOC was estimated to be 190K/QALY and 109 million at the WTP of 275K/QALY for the healthcare sector and the societal perspectives, respectively.
Conclusion: In the model simulation, the novel AD treatments incurred substantial costs with modest clinical benefits, with donanemab adding the highest cost. Assuming the treatment costs based on WAC, only lecanemab was found likely to be cost-effective under a WTP of $200K/QALY from the modified societal perspective. The cost-effectiveness of the mAbs is substantially influenced by the patient’s age at the treatment initiation, patient health state utility values at earlier AD states, and the drug acquisition costs
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