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Varying Periods (varying + period)
Selected AbstractsEstimating lifetime or episode-of-illness costs under censoringHEALTH ECONOMICS, Issue 9 2010Anirban Basu Abstract Many analyses of healthcare costs involve use of data with varying periods of observation and right censoring of cases before death or at the end of the episode of illness. The prominence of observations with no expenditure for some short periods of observation and the extreme skewness typical of these data raise concerns about the robustness of estimators based on inverse probability weighting (IPW) with the survival from censoring probabilities. These estimators also cannot distinguish between the effects of covariates on survival and intensity of utilization, which jointly determine costs. In this paper, we propose a new estimator that extends the class of two-part models to deal with random right censoring and for continuous death and censoring times. Our model also addresses issues about the time to death in these analyses and separates the survival effects from the intensity effects. Using simulations, we compare our proposed estimator to the inverse probability estimator, which shows bias when censoring is large and covariates affect survival. We find our estimator to be unbiased and also more efficient for these designs. We apply our method and compare it with the IPW method using data from the Medicare,SEER files on prostate cancer. Copyright © 2010 John Wiley & Sons, Ltd. [source] The clinical effectiveness of length of bed rest for patients recovering from trans-femoral diagnostic cardiac catheterisationINTERNATIONAL JOURNAL OF EVIDENCE BASED HEALTHCARE, Issue 4 2008Sek Ying Chair RN MBA PhD Background, Cardiac catheterisation plays a vital role in the diagnosis and evaluation of cardiac conditions. The goal of management of patients after cardiac catheterisation is to reduce the risk of development of any local or prolonged vascular complications, in particular bleeding and haematoma formation at the puncture site. Bed rest and immobilisation of the affected leg are recommended practices to ensure adequate haemostasis at the femoral arterial puncture site and prevent complications. Objectives, The objective of this review was to present the best available evidence for the optimal length of bed rest after trans-femoral diagnostic cardiac catheterisation. The main outcome of interest was the incidence of bleeding and haematoma formation following varying periods of bed rest. Search strategy, We searched the following databases: CINAHL, Medline, Cochrane Library, Current Contents, EBSCO, Web of Science, Embase, British Nursing Index, Controlled clinical trials database, Google Scholar. Reference lists of relevant articles and conference proceedings were searched. We also contacted key organisations and researchers in the field. Selection criteria, All randomised and quasi-randomised controlled trials that compared the effects of different lengths of bed rest following trans-femoral diagnostic cardiac catheterisation on patient outcomes were considered for inclusion in the review. Data collection and analysis, Eligibility of the trials for inclusion in the review, details of eligible trials and the methodological quality of the trials were assessed independently by two reviewers. Odds ratios (OR) for dichotomous data and a weighted mean difference for continuous data were calculated with 95% confidence intervals (CI). Where synthesis was inappropriate, trials were considered separately. Main results, Eighteen trials involving a total of 4294 participants were included in the review. One trial included three treatment groups. In seven trials among 747 people there was no significant difference in the incidence of bleeding following six or less than 6 h of bed rest (OR 1.47; 95% CI 0.60, 3.64). Likewise, there was no significant difference in the incidence of bleeding following bed rest at other time periods. In eight trials involving 2272 patients there was no significant difference in the incidence of haematoma formation following 6 or less than 6 h of bed rest (OR 0.82; 95% CI 0.59, 1.16). Significantly fewer patients randomised to less than 6 h of bed rest complained of back pain. The odds of developing back pain at 4 (OR 24.60; 95% CI 1.29, 469) and 24 h (OR 2.47; 95% CI 1.16, 5.23) following coronary catheterisation was significantly higher among patients randomised to 6 compared with 3 h of bed rest. Authors' conclusions, There is evidence of no benefit relating to bleeding and haematoma formation in patients who have more than 3 h of bed rest following trans-femoral diagnostic cardiac catheterisation. However, there is evidence of benefit relating to decreased incidence and severity of back pain and cost-effectiveness following 3 h of bed rest. There is suggestive but inconclusive evidence of a benefit from bed rest for 2 h following trans-femoral cardiac catheterisation. Clinicians should consider a balance between avoiding increased risk of haematoma formation following 2,2.5 h of bed rest and circumventing back pain following more than 4 h of bed rest. [source] Temporal analysis of a very large topically categorized Web query logJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 2 2007Steven M. Beitzel The authors review a log of billions of Web queries that constituted the total query traffic for a 6-month period of a general-purpose commercial Web search service. Previously, query logs were studied from a single, cumulative view. In contrast, this study builds on the authors' previous work, which showed changes in popularity and uniqueness of topically categorized queries across the hours in a day. To further their analysis, they examine query traffic on a daily, weekly, and monthly basis by matching it against lists of queries that have been topically precategorized by human editors. These lists represent 13% of the query traffic. They show that query traffic from particular topical categories differs both from the query stream as a whole and from other categories. Additionally, they show that certain categories of queries trend differently over varying periods. The authors key contribution is twofold: They outline a method for studying both the static and topical properties of a very large query log over varying periods, and they identify and examine topical trends that may provide valuable insight for improving both retrieval effectiveness and efficiency. [source] Sustainability of humoral responses to varicella vaccine in pediatric transplant recipients following a pretransplantation immunization strategyPEDIATRIC TRANSPLANTATION, Issue 8 2009Michelle Barton Abstract:, Varicella infections pose serious challenges for organ transplant recipients. To determine the safety and immunogenicity of the OMVV and determine the maintenance of OMVV responses in transplanted subjects at varying periods of immunosuppression within the first two yr following transplantation. Eligible subjects given a two-dose OMVV pretransplantation were monitored for AE. Antibody levels were assessed at baseline, six wk post-OMVV, pretransplantation and up to 24 months post-transplantation. Seroprotection was defined as ,5 gpEU. Twenty-one seronegative children were vaccinated. Following 42 doses, no vaccine-related serious AE occurred. Mab_titer were 17.8 (5.7,910.2) and 183.5 EU (18.8,8116.4) at six and 12 wk, respectively (p < 0.0001). Fourteen (66.7%) participants were transplanted at a median of 16 months (1.5,56) following OMVV and had Mab_titer of 27.2 EU (9.0,236.2) just prior to transplantation. Of 11 who had post-transplantation serology, seroprotection was sustained at three, six and 12 months post-transplantation in 10/11, 12/12 and 8/10 subjects. In five of six subjects with two-yr follow-up, antibody levels remained seroprotective. No breakthrough varicella infections occurred. The receipt of OMVV prior to transplantation induced humoral responses which persisted in the early months following transplantation and up to two yr post-transplantation and was not associated with any serious adverse consequences. [source] | ||||||||||