Community and patient values for preventing herpes zoster
ABSTRACT The US Advisory Committee on Immunization Practices has recently recommended a new vaccine against herpes zoster (shingles) for routine use in adults aged > or =60 years. However, estimates of the cost effectiveness of this vaccine vary widely, in part because of gaps in the data on the value of preventing herpes zoster. Our aims were to (i) generate comprehensive information on the value of preventing a range of outcomes of herpes zoster; (ii) compare these values among community members and patients with shingles and post-herpetic neuralgia (PHN); and (iii) identify clinical and demographic characteristics that explain the variation in these values.
Community members drawn from a nationally representative survey research panel (n = 527) completed an Internet-based survey using time trade-off and willingness-to-pay questions to value a series of scenarios that described cases of herpes zoster with varying pain intensities (on a scale of 0 to 10, where 0 represents no pain and 10 represents the worst imaginable pain) and duration (30 days to 1 year). Patients with shingles (n = 382) or PHN (n = 137) [defined as having symptoms for > or =90 days] from two large healthcare systems completed telephone interviews with similar questions to the Internet-based survey and also answered questions about their current experience with herpes zoster. We constructed generalized linear mixed models to evaluate the associations between demographic and clinical characteristics, the length and intensity of the health states and time trade-off and willingness-to-pay values.
In time trade-off questions, community members offered a mean of 89 (95% CI 24, 182) discounted days to avoid the least severe scenario (pain level of 3 for 1 month) and a mean of 162 (95% CI 88, 259) discounted days to avoid the most severe scenario (pain level of 8 for 12 months). Compared with patients with shingles, community members traded more days to avoid low-severity scenarios but similar numbers of days to avoid high-severity scenarios. Compared with patients with PHN, community members traded fewer days to avoid high-severity scenarios. In multivariate analyses, older age was the only characteristic significantly associated with higher time trade-off values. In willingness-to-pay questions, community members offered a mean of $US450 (95% CI 203, 893) to avoid pain of level 3 for 1 month and a mean of $US1384 (95% CI 873, 2050) [year 2005 values] to avoid pain of level 8 for 12 months. Community members traded less money than patients with either shingles or PHN to avoid both low- and high-severity scenarios (p-values <0.05 to <0.001). In multivariate models, male gender, higher income and having experienced shingles or PHN were associated with higher willingness to pay to avoid herpes zoster. When patients were asked to assign a value to avoiding their own case of herpes zoster, those with shingles assigned a mean of 67 days or $US2319, while those with PHN assigned a mean of 206 days or $US18 184. Both the time and monetary value traded were associated with the maximum intensity of the pain the individual had experienced, but neither was associated with the duration of the pain.
We believe that this study provides the most comprehensive information to date on the value individuals place on preventing herpes zoster, and it includes the only such valuation from nationally representative community members as well as patients with herpes zoster. Community members would trade substantial amounts of time or money to avoid herpes zoster, even in the least severe scenarios. The time trade-off results in this study may differ from those in other studies because of important differences in methods of assessing health utilities. Consideration of both community and patient perspectives is crucial to help decision makers fully determine the implications of their policies now that a vaccine against herpes zoster is available.
- SourceAvailable from: Pi-Chung Wang
Conference Paper: Fast packet classification through tuple reduction and lookahead caching[Show abstract] [Hide abstract]
ABSTRACT: Packet classification is a technique that classifies the flows into different classes. Nowadays the packet classification plays an important role for many new Internet services. Rectangle search is a well-known packet classification scheme which is based on multiple hash accesses for different filter length. It shows good scalability with respect to the number of filters; however, the lookup performance is not fast enough. For example, through experiments, each packet classification takes about 40 hash accesses in a 100,000-filter database and each hash access may take more than one memory access. Obviously, this is not capable to provide gigabits throughput. We propose an efficient scheme to improve the rectangle search. The scheme consists of two parts. In the first part, the "tuple reduction algorithm" based on filter duplication is proposed. In spite of the increased number of filters, the pre-computation information is dramatically reduced. The performance has increased two times while only about one quarter storage is required. Secondly, we propose a novel "lookahead caching" which can further improve the lookup performance. The basic idea is to find out the "un-matched" case for each incoming packet, thus it is different from the traditional caching mechanism. The experimental results indicate that the proposed scheme can fulfill OC-192 throughput.Networks, 2002. ICON 2002. 10th IEEE International Conference on; 02/2002
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ABSTRACT: In particle swarm optimization (PSO), swarm intelligence is utilized when the velocities of particles are updated depending on their own experience and shared information, which is favorable for avoiding local optima. But frequently updating velocities weaken local exploitation abilities of particles and slow down convergence. In this paper, relaxation-velocity-update (RVU) strategy is incorporated into PSO algorithm to accelerate convergence. RVU strategy suggests that the velocity should be updated only when the particle cannot further improve the fitness with its previous velocity, rather than in every iteration. Standard linearly decreasing weight PSO (LDW-PSO) and LDW-PSO with RVU strategy (LDW-RVU-PSO) are compared on three well-known benchmark functions. The results show that RVU strategy significantly improves the convergence speed of LDW-PSO.Machine Learning and Cybernetics, 2004. Proceedings of 2004 International Conference on; 09/2004
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ABSTRACT: BACKGROUND: Nearly 1 million new episodes of herpes zoster (HZ) occur annually in the US, yet little is known about the medical resource utilization (RU) and costs associated with HZ and its complications. OBJECTIVES: To describe the medical RU and cost burden of HZ in the first 90 days and the first year after diagnosis from the health insurer perspective and to stratify this burden for patients diagnosed with post-herpetic neuralgia (PHN) and those who are immunocompromised. In addition, this study explores costs from the societal perspective as a result of work loss in the first year after diagnosis. METHODS: The medical RU and cost data were obtained from the MarketScan Research Database for the years 1998-2003. This database contains inpatient, outpatient and prescription drug data for approximately 14 million individuals of all ages, covered under a variety of fee-for-service and capitated provider reimbursement arrangements, including those with Medicare and private insurance. The work loss estimates were based on the MarketScan Health and Productivity Management Database. Claims for services incurred between 1 January 1998 and 31 December 2003 were screened to identify a cohort of HZ patients based on the presence of at least one International Classification of Diseases, 9th Revision (ICD-9) diagnosis code 053.xx. Each patient was assigned an index date based on the earliest observed occurrence of an HZ diagnosis. A cohort of PHN patients was identified as a subset of the HZ cohort with ICD-9 codes 053.12, 053.13, 053.19 or 729.2x in the period of 90 days to 12 months after the index date. Multivariable regression was used to compare HZ cases with matched controls after adjusting for demographic characteristics, insurance status, co-morbidities and medical expenditure in the 6 months prior to diagnosis for each of the endpoints. Separate regression models were developed, in which age and immune status were stratified. All costs were adjusted to March 2008 values using the medical care component of the Consumer Price Index. The average per patient cost of all HZ cases was $US605 in the first 90 days after diagnosis and $US1052 at 1 year. For the subset with PHN, the average per patient cost of HZ at 1 year was $US3815. For the subset with an immunocompromising condition, the average HZ cost at 1 year was $US1745. The majority of the costs were the result of outpatient visits and prescription drugs. The subset of HZ cases that had both absence hour and short-term disability (STD) records available had 26.5 absence hours and 2.9 STD days. Healthcare utilization, medical care costs and work loss all increased with age for all HZ cases. Based on the results from the present study, the direct medical cost burden of HZ in the US is high, exceeding $US1000 per HZ patient. This direct medical cost may be nearly twice as high in immunocompromised patients and four times as high in the subset of HZ cases with PHN. The direct medical cost burden of HZ may exceed $US1 billion annually in the US. The majority of medical RU and cost burden is incurred by the elderly. Although many people with HZ may no longer be in the workforce, HZ does contribute to lost work time.PharmacoEconomics 01/2009; 27(9):781-92. DOI:10.2165/11317560-000000000-00000 · 3.34 Impact Factor