Biomedical subjects

Keith Abrams

Publications and source records attributed to Keith Abrams.

8 recordsLinked to original sources

PubMed2006

Clinically overt postpartum urinary retention after vaginal delivery: a retrospective case-control study.

We set out to determine the incidence of symptomatic postpartum urinary retention (PUR) after vaginal delivery and to establish any associated risk factors. We carried out a retrospective case-control study of women having PUR after vaginal delivery from 2001 to 2005. Four controls, matched for date of delivery, were selected for each case in univariate and multivariate conditional logistic regression analyses. There were 15,757 deliveries and 30 cases of PUR (incidence 0.2%). Median duration of PUR was 19 days (range 3-85). Eighty percent were managed with intermittent self-catheterization. The use of regional analgesia increased the risk of PUR [odds ratio (OR) 6.33, 95% confidence interval (CI) 2.01-19.96], while ethnicity (Caucasian vs Asian) reduced the risk (OR 0.27, CI 0.08-0.85) (p<0.05). PUR is uncommon but carries significant morbidity. Epidural analgesia and Asian ethnic origin increase the risk. We recommend routine catheterization for up to 24 h after delivery after epidural analgesia.

Adult↗

PubMed2006

Bayesian methods for evidence synthesis in cost-effectiveness analysis.

Recently, health systems internationally have begun to use cost-effectiveness research as formal inputs into decisions about which interventions and programmes should be funded from collective resources. This process has raised some important methodological questions for this area of research. This paper considers one set of issues related to the synthesis of effectiveness evidence for use in decision-analytic cost-effectiveness (CE) models, namely the need for the synthesis of all sources of available evidence, although these may not 'fit neatly' into a CE model. Commonly encountered problems include the absence of head-to-head trial evidence comparing all options under comparison, the presence of multiple endpoints from trials and different follow-up periods. Full evidence synthesis for CE analysis also needs to consider treatment effects between patient subpopulations and the use of nonrandomised evidence. Bayesian statistical methods represent a valuable set of analytical tools to utilise indirect evidence and can make a powerful contribution to the decision-analytic approach to CE analysis. This paper provides a worked example and a general overview of these methods with particular emphasis on their use in economic evaluation.

Bayes Theorem↗

PubMed2005

Management of non-ST-elevation acute coronary syndromes: how cost-effective are glycoprotein IIb/IIIA antagonists in the UK National Health Service?

BACKGROUND: The glycoprotein IIb/IIIa antagonists (GPAs) represent a new class of drugs to prevent platelet aggregation in the acute treatment of non-ST-elevation acute coronary syndromes (NSTE-ACS). Systematic reviews have identified serious limitations in published cost-effectiveness analyses, including a lack of UK-specific studies and an absence of studies comparing different protocols for the use of GPAs. METHODS: A model was developed to assess the cost effectiveness of a variety of protocols employing GPAs for patients presenting with NSTE-ACS in the UK. The perspective of the UK National Health Service was adopted, with outcomes in terms of quality-adjusted life-years (QALYs). Four treatment strategies were evaluated: GPAs as part of initial medical management (Strategy 1); GPAs in patients with planned percutaneous coronary interventions (PCIs; Strategy 2); GPAs as an adjunct to the PCI procedure (Strategy 3); and no GPAs (Strategy 4). Baseline event rates and costs were taken from a UK observational study of ACS patients and relative risk reductions from GPAs were taken from a meta analysis of trials. Long-term costs and QALYs were estimated using data from a UK longitudinal study. RESULTS: The most cost-effective use of GPAs is likely to be Strategy 1, with an incremental cost per QALY gained of between pound4605 to pound10,343. Focusing this use of GPAs only on the subgroup of patients at high risk appears to represent the most cost-effective use of NHS resources. CONCLUSIONS: Medical management of patients with NSTE-ACS using GPAs is the most cost-effective use of resources, particularly if targeted to higher risk subgroups.

Coronary Disease↗

PubMed2005

Use of evidence in decision models: an appraisal of health technology assessments in the UK since 1997.

OBJECTIVES: To review the sources and quality of evidence used in the development of economic decision models in health technology assessments (HTAs). METHODS: All economic decision models developed as part of the NHS Research and Development HTA Programme between 1997 and 2003 were reviewed. Quality of evidence was assessed using a hierarchy of data sources developed for economic analyses. RESULTS: Decision models are parameterized using diverse sources of evidence (e.g. randomized controlled trials, observational studies, expert opinion). Evidence on the main clinical effect was mostly identified and quality assessed as part of the companion systematic review/meta-analysis of the HTA and therefore reported in a transparent and reproducible way. For the other model inputs (i.e. adverse events, baseline clinical data, resource use and utilities), the search strategies for identifying relevant evidence were rarely made explicit and in a number of reports the sources of specific evidence were unclear due to poor reporting. CONCLUSIONS: A more formal and replicable approach to identification and assessment of quality of model inputs is required to reduce the 'black box' nature of decision models, and lead to less scepticism regarding model outputs.

Biomedical Technology↗

PubMed2003

Modelling the cost effectiveness of interferon beta and glatiramer acetate in the management of multiple sclerosis. Commentary: evaluating disease modifying treatments in multiple sclerosis.

OBJECTIVE: To evaluate the cost effectiveness of four disease modifying treatments (interferon betas and glatiramer acetate) for relapsing remitting and secondary progressive multiple sclerosis in the United Kingdom. DESIGN: Modelling cost effectiveness. SETTING: UK NHS. PARTICIPANTS: Patients with relapsing remitting multiple sclerosis and secondary progressive multiple sclerosis. MAIN OUTCOME MEASURES: Cost per quality adjusted life year gained. RESULTS: The base case cost per quality adjusted life year gained by using any of the four treatments ranged from pound 42,000 (66,469 dollars; 61,630 euro) to pound 98,000 based on efficacy information in the public domain. Uncertainty analysis suggests that the probability of any of these treatments having a cost effectiveness better than pound 20,000 at 20 years is below 20%. The key determinants of cost effectiveness were the time horizon, the progression of patients after stopping treatment, differential discount rates, and the price of the treatments. CONCLUSIONS: Cost effectiveness varied markedly between the interventions. Uncertainty around point estimates was substantial. This uncertainty could be reduced by conducting research on the true magnitude of the effect of these drugs, the progression of patients after stopping treatment, the costs of care, and the quality of life of the patients. Price was the key modifiable determinant of the cost effectiveness of these treatments.

Cost-Benefit Analysis↗

PubMed2002

Randomized controlled trial comparing the efficacy of a video and information leaflet versus information leaflet alone on patient knowledge about surveillance and cancer risk in ulcerative colitis.

BACKGROUND AND AIMS: Knowledge of colorectal cancer risk in patients with ulcerative colitis is inadequate. The authors aimed to improve knowledge in a sample of patients and determine whether this was best achieved by a simple information leaflet or by watching a video reading a leaflet. MATERIALS AND METHODS: Patients (n = 124) were recruited into a randomized controlled trial conducted from the gastroenterology outpatient departments of two Leicester hospitals. Participants completed a questionnaire prior to receiving the leaflet or viewing the video, immediately afterward, and 1 month later. RESULTS: One hundred fifteen questionnaires were returned (response rate = 93%). Both videos and leaflets increased knowledge with mean percentage improvements in scores of 71% (95% CI = 40.2-100) and 49% (95% CI = 32.1-66), respectively. However, the difference between the two interventions was not statistically significant (Difference = 22%, 95% CI = -56.3-13.2, p = 0.2). After 1 month, knowledge levels decreased in both groups to 55% (95% CI = 33.2-75.8; video plus leaflet) and 36% (95% CI = 23.7-48.6; leaflet alone). CONCLUSIONS: Leaflets and videos have an important role in reinforcing information provided by clinicians. However, there appears to be no immediate or prolonged advantage of a video over and above that of a simple information leaflet. The cost implications of producing a video, such as extra staff time, need to be weighed against the minor benefit that this medium has to offer.

Adult↗

PubMedDate not supplied

The importance of effect mechanism in the design and interpretation of clinical trials: the role of magnesium in acute myocardial infarction.

The design and interpretation of randomized clinical trials and of meta-analyses of trials should be informed by a biologically plausible hypothesis of treatment effect. Without some insight on likely mechanism, trial conditions may not be optimum to allow a true treatment effect to be detected. Judgments on mechanism underpin decisions on the appropriateness of pooling studies in meta-analysis. Where statistical heterogeneity of trial results is found, the possibility of true biological effect modification can only be assessed by considering potential treatment mechanisms. These can then be tested in carefully designed laboratory models. Meta-analysis of 12 randomized controlled trials of intravenous Mg(2+) in acute myocardial infarction gives a null effect (odds ratio 1.02, 95% CI 0.96 to 1.08) with a fixed effects model, but with strong evidence of heterogeneity (P <.0001) due to a single large study in which Mg(2+) was generally given late and after fibrinolytic treatment. A random effects model gives a pooled odds ratio 0.61 (95% CI 0.43 to 0.87, P = 0.006). Laboratory models show that timing of Mg(2+) administration before or after reperfusion critically determines whether myocardial protection occurs.

Humans↗

PubMedDate not supplied

An iterative Bayesian approach to health technology assessment: application to a policy of preoperative optimization for patients undergoing major elective surgery.

PURPOSE: This article presents an iterative framework for managing the dynamic process of health technology assessment. The framework uses Bayesian statistical decision theory and value of information (VOI) analysis to inform decision making regarding appropriate patient management and to direct future research effort over the lifetime of a technology. Within the article, the framework is applied to a policy decision regarding preoperative patient management before major elective surgery, for which trial data are available. METHOD: The evidence available prior to the trial is used to determine the appropriate method of patient management and to ascertain whether, at the time of commissioning, the trial was potentially worthwhile. The prior information is then updated with the trial data via a Bayesian analysis using informative priors. This post trial information set is then used to reassess the appropriate method for patient management and to determine whether there is a requirement for any further research. RESULTS: Prior to the trial, preoperative optimization with dopexamine is identified as the appropriate method of patient management. The results of the VOI analysis suggest that a short-term trial was potentially worthwhile (population expected value of perfect information [EVPI] = 48 million pounds sterling). Following the trial, the uncertainty surrounding the choice of appropriate patient management and the potential worth of further research had increased (population EVPI = 67 million pounds sterling). CONCLUSIONS: The article demonstrates the value and practicality of applying the iterative framework to the dynamic process of health technology assessment. It is only by formally incorporating all of the information available to decision makers, through informed priors, that the appropriate decisions can be made.

Aged↗