Pegylated interferon alpha-2b for patients with HCV recurrence and graft fibrosis following liver transplantation

Chronic hepatitis C is a principal indication for liver transplantation. Recurrent viral infection is inevitable and graft disease is common. We report tolerability, safety and efficacy of pegylated interferon alpha 2b (PEG-IFN) monotherapy for patients with hepatitis C virus (HCV) recurrence and fibrosis after liver transplantation. Repeated measurements of serum HCV titer permitted assessment of the kinetics of the antiviral response for all patients. We screened 63 patients transplanted for HCV at our center for antiviral treatment, 14 were eligible and treated, but only 6 completed the proposed 52 weeks of therapy. Eight were withdrawn because of severe/life-threatening side effects/events, including liver dysfunction (4 patients). None of those 8 achieved a sustained virological response (SVR). Five of 6 who completed treatment were HCV RNA negative at the end of treatment, and 2 achieved an SVR. Viral kinetics were similar to published observations for treatment of non-transplanted HCV patients. Patients with genotype non-1 infection displayed a more rapid decline of viral titer than was observed for genotype 1 infection. Post-transplant HCV patients are frequently unsuitable for, or intolerant of PEG-IFN. Liver dysfunction was a major concern.

The cost-effectiveness of screening for oral cancer in primary care

OBJECTIVES

To use a decision-analytic model to determine the incremental costs and outcomes of alternative oral cancer screening programmes conducted in a primary care environment.

DESIGN

The cost-effectiveness of oral cancer screening programmes in a number of primary care environments was simulated using a decision analysis model. Primary data on actual resource use and costs were collected by case note review in two hospitals. Additional data needed to inform the model were obtained from published costs, from systematic reviews and by expert opinion using the Trial Roulette approach. The value of future research was determined using expected value of perfect information (EVPI) for the decision to screen and for each of the model inputs.

SETTING

Hypothetical screening programmes conducted in a number of primary care settings. Eight strategies were compared: (A) no screen; (B) invitational screen--general medical practice; (C) invitational screen--general dental practice; (D) opportunistic screen--general medical practice; (E) opportunistic screen--general dental practice; (F) opportunistic high-risk screen--general medical practice; (G) opportunistic high-risk screen--general dental practice; and (H) invitational screen--specialist.

PARTICIPANTS

A hypothetical population over the age of 40 years was studied.

MAIN OUTCOME MEASURES

The main measures were mean lifetime costs and quality-adjusted life-years (QALYs) of each alternative screening scenario and incremental cost-effectiveness ratios (ICERs) to determine the additional costs and benefits of each strategy over another.

RESULTS

No screening (strategy A) was always the cheapest option. Strategies B, C, E and H were never cost-effective and were ruled out by dominance or extended dominance. Of the remaining strategies, the ICER for the whole population (age 49-79 years) ranged from pound 15,790 to pound 25,961 per QALY. Modelling a 20% reduction in disease progression always gave the lowest ICERs. Cost-effectiveness acceptability curves showed that there is considerable uncertainty in the optimal decision identified by the ICER, depending on both the maximum amount that the NHS may be prepared to pay and the impact that treatment has on the annual malignancy transformation rate. Overall, however, high-risk opportunistic screening by a general dental or medical practitioner (strategies F and G) may be cost-effective. EVPIs were high for all parameters with population values ranging from pound 8 million to pound 462 million. However, the values were significantly higher in males than females but also varied depending on malignant transformation rate, effects of treatment and willingness to pay. Partial EVPIs showed the highest values for malignant transformation rate, disease progression, self-referral and costs of cancer treatment.

CONCLUSIONS

Opportunistic high-risk screening, particularly in general dental practice, may be cost-effective. This screening may more effectively be targeted to younger age groups, particularly 40-60 year olds. However, there is considerable uncertainty in the parameters used in the model, particularly malignant transformation rate, disease progression, patterns of self-referral and costs. Further study is needed on malignant transformation rates of oral potentially malignant lesions and to determine the outcome of treatment of oral potentially malignant lesions. Evidence has been published to suggest that intervention has no greater benefit than 'watch and wait'. Hence a properly planned randomised controlled trial may be justified. Research is also needed into the rates of progression of oral cancer and on referral pathways from primary to secondary care and their effects on delay and stage of presentation.

Neuroprotective effects of metabotropic glutamate receptor ligands in a 6-hydroxydopamine rodent model of Parkinson's disease

Increasing evidence implicates glutamate-mediated excitotoxicity as a contributory factor in dopaminergic cell death in the substantia nigra pars compacta (SNc) in Parkinson's disease (PD). Previous studies have suggested that metabotropic glutamate receptor (mGluR) ligands are neuroprotective against excitotoxicity in vitro. In the present study, the neurotoxin 6-hydroxydopamine (6-OHDA) produced a significant loss (61.2 +/- 8.9%; P < 0.01) of tyrosine hydroxylase-immunopositive (TH+) cells in both the SNc and striatal dopamine (58.02 +/- 1.27%; P < 0.05) in control male Sprague-Dawley rats. Both losses were significantly attenuated by sub-chronic (7 day) treatment with the Group I mGluR antagonists, 2-methyl-6(phenylethynyl)-pyridine (MPEP) or (S)-(+)-alpha-amino-4-carboxy-2-methylbenzeneacetic acid (LY367385); the Group II mGluR agonist (2R,4R)-4-aminopyrrolidine-2,4-dicarboxylate (2R,4R-APDC); or the Group III mGluR agonist, L(+)-2-amino-4-phosphonobutyric acid (L-AP4). These data demonstrate a neuroprotective action of mGluR ligands in vivo against 6-OHDA toxicity that has important implications for the treatment of PD.

Cost-effectiveness of alternative strategies for the initial medical management of non-ST elevation acute coronary syndrome: systematic review and decision-analytical modelling

OBJECTIVES

To identify and prioritise key areas of clinical uncertainty regarding the medical management of non-ST elevation acute coronary syndrome (ACS) in current UK practice.

DATA SOURCES

Electronic databases. Consultations with clinical advisors. Postal survey of cardiologists.

REVIEW METHODS

Potential areas of important uncertainty were identified and 'decision problems' prioritised. A systematic literature review was carried out using standard methods. The constructed decision model consisted of a short-term phase that applied the results of the systematic review and a long-term phase that included relevant information from a UK observational study to extrapolate estimated costs and effects. Sensitivity analyses were undertaken to examine the dependence of the results on baseline parameters, using alternative data sources. Expected value of information analysis was undertaken to estimate the expected value of perfect information associated with the decision problem. This provided an upper bound on the monetary value associated with additional research in the area.

RESULTS

Seven current areas of clinical uncertainty (decision problems) in the drug treatment of unstable angina patients were identified. The agents concerned were clopidogrel, low molecular weight heparin, hirudin and intravenous glycoprotein antagonists (GPAs). Twelve published clinical guidelines for unstable angina or non-ST elevation ACS were identified, but few contained recommendations about the specified decision problems. The postal survey of clinicians showed that the greatest disagreement existed for the use of small molecule GPAs, and the greatest uncertainty existed for decisions relating to the use of abciximab (a large molecule GPA). Overall, decision problems concerning the GPA class of drugs were considered to be the highest priority for further study. Selected papers describing the clinical efficacy of treatment were divided into three groups, each representing an alternative strategy. The strategy involving the use of GPAs as part of the initial medical management of all non-ST elevation ACS was the optimal choice, with an incremental cost-effectiveness ratio (ICER) of 5738 pounds per quality-adjusted life-year (QALY) compared with no use of GPAs. Stochastic analysis showed that if the health service is willing to pay 10,000 pounds per additional QALY, the probability of this strategy being cost-effective was around 82%, increasing to 95% at a threshold of 50,000 pounds per QALY. A sensitivity analysis including an additional strategy of using GPAs as part of initial medical management only in patients at particular high risk (as defined by age, ST depression or diabetes) showed that this additional strategy was yet more cost-effective, with an ICER of 3996 pounds per QALY compared with no treatment with GPA. Value of information analysis suggested that there was considerable merit in additional research to reduce the level of uncertainty in the optimal decision. At a threshold of 10,000 pounds per QALY, the maximum potential value of such research in the base case was calculated as 12.7 million pounds per annum for the UK as a whole. Taking account of the greater uncertainty in the sensitivity analyses including clopidogrel, this figure was increased to approximately 50 million pounds.

CONCLUSIONS

This study suggests the use of GPAs in all non-ST elevation ACS patients as part of their initial medical management. Sensitivity analysis showed that virtually all of the benefit could be realised by treating only high-risk patients. Further clarification of the optimum role of GPAs in the UK NHS depends on the availability of further high-quality observational and trial data. Value of information analysis derived from the model suggests that a relatively large investment in such research may be worthwhile. Further research should focus on the identification of the characteristics of patients who benefit most from GPAs as part of medical management, the comparison of GPAs with clopidogrel as an adjunct to standard care, follow-up cohort studies of the costs and outcomes of high-risk non-ST elevation ACS over several years, and exploring how clinicians' decisions combine a normative evidence-based decision model with their own personal behavioural perspective.

Iatrogenic pseudoaneurysms of the extrahepatic arterial vasculature: management and outcome

BACKGROUND

Pseudoaneurysms of the extrahepatic arterial vasculature are relatively uncommon lesions following surgery and trauma. In this report we analyze the presentation, management and outcomes of these vascular lesions. Of the related surgical procedures, the reported incidence is highest following laparoscopic cholecystectomy. We hereby analyze the literature on this subject and report our experience, specifically with extrahepatic pseudoaneurysms, drawing an important distinction from intrahepatic pseudoaneurysms.

METHODS

From September 1995 until July 2004, six patients, including three males and three females with a mean age of 67 years, were treated for seven extrahepatic arterial pseudoaneurysms. Patients were evaluated by endoscopy, ultrasound, computerized tomography, and angiography. Management included coil embolization or arterial ligation and/or hepatic resection.

RESULTS

The mean pseudoaneurysm size was 4.9-cm (range 1.0-11.0-cm) and the locations included the right hepatic artery (n = 5), inferior pancreaticoduodenal artery (n = 1), and gastroduodenal artery (n = 1). All six patients had prior surgical or percutaneous procedures. Median latency period between the original procedure and treatment of pseudoaneurysm was 17 weeks (range one month-16 years). Clinical features ranged from the dramatic presentation of hypotension secondary to intraperitoneal aneurysmal rupture to the subtle presentation of obstructive jaundice secondary to pseudoaneurysm mass effect. The range of patient presentations created diagnostic challenges, proving that accurate diagnosis is made only by early consideration of pseudoaneurysm. Management was ligation of the right hepatic artery (n = 4) and embolization of the pseudoaneurysms (n = 2). Post-treatment sequelae included liver failure requiring liver transplant (n = 1), intrahepatic biloma requiring percutaneous drainage (n = 1) and cholangitis with right hepatic duct strictures requiring right lobectomy and biliary reconstruction (n = 1). These complications followed arterial ligation, with no complications resulting from embolization. All six patients are alive and well after a mean follow-up of 53 months.

CONCLUSIONS

Our six patients demonstrate the diversity and unpredictability with which a pseudoaneurysm of the extrahepatic arterial vasculature may present in terms of initial symptoms, prior procedures, and the latency period between presentation and prior procedure. Through our experience and an analysis of the literature, we recommend a diagnostic and management approach for these patients.

Global surveillance for chemical incidents of international public health concern

OBJECTIVE

In December 2001, an expert consultation convened by WHO identified strengthening national and global chemical incident preparedness and response as a priority. WHO is working towards this objective by developing a surveillance and response system for chemical incidents. This report describes the frequency, nature and geographical location of acute chemical incidents of potential international concern from August 2002 to December 2003.

METHODS

Acute chemical incidents were actively identified through several informal (e.g. Internet-based resources) and formal (e.g. various networks of organizations) sources and assessed against criteria for public health emergencies of international concern using the then proposed revised International Health Regulations (IHR). WHO regional and country offices were contacted to obtain additional information regarding identified incidents.

FINDINGS

Altogether, 35 chemical incidents from 26 countries met one or more of the IHR criteria. The WHO European Region accounted for 43% (15/35) of reports. The WHO Regions for Africa, Eastern Mediterranean and Western Pacific each accounted for 14% (5/35); South-East Asia and the Americas accounted for 9% (3/35) and 6% (2/35), respectively. Twenty-three (66%) events were identified within 24 hours of their occurrence.

CONCLUSION

To our knowledge this is the first global surveillance system for chemical incidents of potential international concern. Limitations such as geographical and language bias associated with the current system are being addressed. Nevertheless, the system has shown that it can provide early detection of important events, as well as information on the magnitude and geographical distribution of such incidents. It can therefore contribute to improving global public health preparedness.

Interventions for preventing bone disease in kidney transplant recipients

BACKGROUND

Patients with chronic kidney disease have significant abnormalities of bone remodelling and calcium homeostasis and are at increased risk of fracture. The fracture risk for a kidney transplant recipient is four times that of the general population and higher than that for a patient on dialysis. Trials reporting the use of bisphosphonates, vitamin D analogues, calcitonin, and hormone replacement therapy to treat bone disease following engraftment exist.

OBJECTIVES

To evaluate the use of interventions for the treatment of bone disease following kidney transplantation.

SEARCH STRATEGY

The Cochrane CENTRAL Register of Controlled Trials (The Cochrane Library - Issue 3 2004), MEDLINE (1966 to August 2004), EMBASE (1980- August 2004) and reference lists were searched without language restriction.

SELECTION CRITERIA

Randomised trials of treatment of bone disease following kidney transplantation were included. Trials of recipients of any transplant other than a kidney transplant including trials of kidney-pancreas transplants were excluded.

DATA COLLECTION AND ANALYSIS

Two authors assessed independently trial quality and extracted data. Statistical analyses were performed using the random effects model and the results expressed as relative risk (RR) with 95% confidence intervals (CI) for dichotomous variables. For continuous variables the weighted mean difference (WMD) and its 95% CI was used.

MAIN RESULTS

Twenty-three eligible trials (1,209 patients) were identified. Seven trials compared more than two interventions. Nineteen trials compared active treatment with placebo, five vitamin D analogue and calcium, six vitamin D analogue alone, twelve bisphosphonates, and four nasal calcitonin. Eight trials compared two active treatments, one 17-beta oestradiol and medroxyprogesterone versus vitamin D analogue, five bisphosphonate versus vitamin D analogue, two vitamin D analogue and calcium versus calcium and one bisphosphonate versus calcitonin. Methodological quality was suboptimal. There were no significant differences between any treatment group for risk of fracture. Bisphosphonate, administered by any route, vitamin D analogue and calcitonin all had a beneficial effect on the bone mineral density at the lumbar spine. Bisphosphonates and vitamin D analogue had a beneficial effect on the bone mineral density at the femoral neck. Few or no data were available for combined hormone replacement, testosterone, selective oestrogen receptor modulators, fluoride or anabolic steroids. All-cause mortality and drug-related toxicity were reported infrequently and there was no statistical difference between treatment groups.

AUTHORS' CONCLUSIONS

No benefit from any intervention known to reduce risk of fracture from bone disease could be demonstrated to reduce fracture incidence in kidney transplant recipients.

Anal intraepithelial neoplasia in heterosexual and homosexual HIV-positive men with access to antiretroviral therapy

BACKGROUND

Studies of human immunodeficiency virus (HIV)-positive men have demonstrated high rates of anal intraepithelial neoplasia (AIN), a precursor to anal carcinoma, mostly in white homosexual men and men not receiving effective antiretroviral therapy (ART).

METHODS

Ninety-two participants--53% Latino, 36% African American, and 40% without a history of receptive anal intercourse (RAI)--were evaluated with a behavioral questionnaire, liquid-based anal cytological testing, Hybrid Capture 2 human papillomavirus (HPV) DNA assay and polymerase chain reaction, and anal colposcopy with biopsy of lesions.

RESULTS

High-risk HPV DNA was identified in 61%, and this was associated with a history of RAI (78% vs. 33%; P<.001); 47% had abnormal cytological results, and 40% had AIN on biopsy. In multivariate analysis, both were associated with a history of RAI (odds ratio [OR], 10 [P<.001] and OR, 3.6 [P=.02], respectively) and lower nadir CD4(+) cell counts (P=.06 and P=.01). Current ART use was protective (OR, 0.09; P<.01 and OR, 0.18; P=.02).

CONCLUSIONS

Although anal infections with high-risk HPV and AIN in HIV-positive men are associated with a history of RAI, both conditions are commonly identified in HIV-positive men without this history. Both lower nadir CD4(+) cell counts and lack of current ART were associated with AIN but not with the detection of anal HPV.

Clinical effectiveness and cost-effectiveness of clopidogrel and modified-release dipyridamole in the secondary prevention of occlusive vascular events: a systematic review and economic evaluation

OBJECTIVES

To examine the clinical effectiveness and cost-effectiveness of two alternative antiplatelet agents, clopidogrel and modified-release (MR)-dipyridamole, relative to prophylactic doses of aspirin for the secondary prevention of occlusive vascular events.

DATA SOURCES

Electronic databases.

REVIEW METHODS

A total of 2906 titles and abstracts were rigorously screened and 441 studies were assessed in detail. Two RCTs were identified. For the assessment of cost-effectiveness, eight reviews were identified. The results were presented in structured tables and as a narrative summary. No additional clinical effectiveness data were presented in either of two company submissions. All economic evaluations (including accompanying models) included in the company submissions were assessed. Following this analysis, if the existing models (company or published) were not sufficient, a de novo model or modified versions of the models were developed.

RESULTS

In the CAPRIE trial the point estimate for the primary outcome, i.e. ischaemic stroke, myocardial infarction (MI) or vascular death, favoured clopidogrel over aspirin, but the boundaries of the confidence intervals raise the possibility that clopidogrel is not more beneficial than aspirin. In terms of the secondary outcomes reported, there was a non-significant trend in favour of clopidogrel over aspirin but the boundaries of the confidence intervals on the relative risks all crossed unity. There was no difference in the number of patients ever reporting any bleeding disorder in the clopidogrel group compared with the aspirin group. The incidences of rash and diarrhoea were statistically significantly higher in the clopidogrel group than the aspirin group. Patients in the aspirin group had a higher incidence of indigestion/nausea/vomiting than patients in the clopidogrel group. Haematological adverse events were rare in both the clopidogrel and aspirin groups. No cases of thrombotic thrombocytopenic purpura were reported in either group. Treatment with MR-dipyridamole alone did not significantly reduce the risk of any of the primary outcomes reported in ESPS-2 compared with treatment with aspirin. ASA-MR-dipyridamole was significantly more effective than aspirin alone in patients with stroke or transient ischaemic attacks (TIAs) at reducing the outcome of stroke and marginally more effective at reducing stroke and/or death. Treatment with ASA-MR-dipyridamole did not statistically significantly reduce the risk of death compared to treatment with aspirin. The number of strokes was statistically significantly reduced in the ASA-MR-dipyridamole group compared with the MR-dipyridamole group. In terms of the other primary outcomes, stroke and/or death and death, the results favoured treatment with ASA-MR-dipyridamole but the findings were not statistically significant. There was no difference in the number of bleeding complications between the ASA-MR-dipyridamole and aspirin groups. The incidence of bleeding complications was significantly lower in the MR-dipyridamole treatment group. More patients in the MR-dipyridamole treatment groups experienced headaches compared to patients receiving treatment with aspirin alone. The York model assessed the cost-effectiveness of differing combinations of treatment strategies in four patient subgroups, under a number of different scenarios. The results of the model were sensitive to the assumptions made in the alternative scenarios, in particular the impact of therapy on non-vascular deaths.

CONCLUSIONS

Clopidogrel was marginally more effective than aspirin at reducing the risk of ischaemic stroke, MI or vascular death in patients with atherosclerotic vascular disease, however, it did not statistically significantly reduce the risk of vascular death or death from any cause compared with aspirin. There was no statistically significant difference in the number of bleeding complications experienced in the clopidogrel and aspirin groups. MR-dipyridamole in combination with aspirin was superior to aspirin alone at reducing the risk of stroke and marginally more effective at reducing the risk of stroke and/or death. Compared with treatment with MR-dipyridamole alone, MR-dipyridamole in combination with aspirin significantly reduced the risk of stroke. Treatment with MR-dipyridamole in combination with aspirin did not statistically significantly reduce the risk of death compared with aspirin. Compared with treatment with MR-dipyridamole alone, bleeding complications were statistically significantly higher in patients treated with aspirin and MR-dipyridamole in combination with aspirin. Due to the assumptions that have to be made, no conclusions could be drawn about the relative effectiveness of MR-dipyridamole, alone or in combination with aspirin, and clopidogrel from the adjusted indirect comparison. The following would apply for a cost of up to GBP20,000-40,000 per additional quality-adjusted life-year. For the stroke and TIA subgroups, ASA-MR-dipyridamole would be the most cost-effective therapy given a 2-year treatment duration as long as all patients were not left disabled by their initial (qualifying) stroke. For a lifetime treatment duration, ASA-MR-dipyridamole would be considered more cost-effective than aspirin as long as treatment effects on non-vascular deaths are not considered and all patients were not left disabled by their initial stroke. In patients left disabled by their initial stroke, aspirin is the most cost-effective therapy. Clopidogrel and MR-dipyridamole alone would not be considered cost-effective under any scenario. For the MI and peripheral arterial disease subgroups, clopidogrel would be considered cost-effective for a treatment duration of 2 years. For a lifetime treatment duration, clopidogrel would be considered more cost-effective than aspirin as long as treatment effects on non-vascular deaths are not considered. It is suggested that the combination of clopidogrel and aspirin should be evaluated for the secondary prevention of occlusive vascular events. Also randomised, direct comparisons of clopidogrel and MR-dipyridamole in combination with aspirin are required to inform the treatment of patients with a history of stroke and TIA, plus trials that compare treatment with clopidogrel and MR-dipyridamole for the secondary prevention of vascular events in patients who demonstrate a genuine intolerance to aspirin.

Clopidogrel used in combination with aspirin compared with aspirin alone in the treatment of non-ST-segment-elevation acute coronary syndromes: a systematic review and economic evaluation

OBJECTIVES

To review systematically the clinical effectiveness and the cost-effectiveness of clopidogrel used in combination with standard therapy including aspirin, compared with standard therapy alone for the treatment of non-ST-segment elevation acute coronary syndromes (ACS).

DATA SOURCES

Electronic databases. Manufacturers' submissions.

REVIEW METHODS

Studies were selected using rigorous criteria. The quality of randomised controlled trials (RCTs) was assessed according to criteria based on NHS CRD Report No. 4, and the quality of systematic reviews was assessed according to the guidelines for the Database of Reviews of Effect (DARE) criteria. The quality of economic evaluations was assessed according to a specifically tailored checklist. The clinical effectiveness and cost-effectiveness of clopidogrel in combination with standard therapy compared with standard therapy alone were synthesised through a narrative review with full tabulation of the results of the included studies. In the economic evaluations, a cost-effectiveness model was constructed using the best available evidence to determine cost-effectiveness in a UK setting.

RESULTS

One RCT (the CURE trial) was a randomised, double-blind, placebo-controlled trial of high quality and showed that clopidogrel in addition to aspirin was significantly more effective than placebo plus aspirin in patients with non-ST-segment elevation ACS for the composite outcome of death from cardiovascular causes, non-fatal myocardial infarction or stroke over the 9-month treatment period. However, clopidogrel was associated with a significantly higher number of episodes of both major and minor bleeding. The results from the five systematic reviews that assessed the adverse events associated with long-term aspirin use showed that aspirin was associated with a significantly higher incidence of haemorrhagic stroke, extracranial haemorrhage and gastrointestinal haemorrhage compared with placebo. Of the cost-effectiveness evidence reviewed, only the manufacturer's submission was considered relevant from the perspective of the NHS. The review of this evidence highlighted potential limitations within the submission in its use of data and in the model structure used. These limitations led to the development of a new model with the aim of providing a more reliable estimate of the cost-effectiveness from the perspective of the UK NHS. This model indicated that clopidogrel appears cost-effective compared with standard care alone in patients with non-ST-elevation ACS as long as the NHS is willing to pay GBP6078 per quality of life year (QALY). The results were most sensitive to the inclusion of additional strategies that assessed alternative treatment durations with clopidogrel. Although treatment with clopidogrel for 12 months remained cost-effective for the overall cohort, provisional findings indicate that the shorter treatment durations may be more cost-effective in patients at low risk.

CONCLUSIONS

The results of the CURE trial indicate that clopidogrel in combination with aspirin was significantly more effective than placebo combined with aspirin in a wide range of patients with ACS. This benefit was largely related to a reduction in Q-wave myocardial infarction. There was no statistically significant benefit in relation to mortality. The trial data suggested that a substantial part of the benefit derived from clopidogrel is achieved by 3 months, with a further small benefit over the remaining 9 months of chronic treatment. The results from the base-case model suggest that treatment with clopidogrel as an adjunct to standard therapy (including aspirin) for 12 months, compared with standard therapy alone, is cost-effective in non-ST elevation ACS patients as long as the health service is willing to pay GBP6078 per additional QALY. However, although treatment with clopidogrel for 12 months remained cost-effective for the overall cohort, provisional findings indicate that the shorter treatment durations may be more cost-effective in patients at low risk. To estimate the exact length of time that clopidogrel in addition to standard therapy should be prescribed for patients with non-ST-segment ACS would require a prospective trial that randomised patients to various durations of therapy. This would accurately assess whether a 'rebound' phenomenon occurs in patients if clopidogrel were stopped after 3 months of treatment.

Long-acting follicle-stimulating hormone analogs containing N-linked glycosylation exhibited increased bioactivity compared with o-linked analogs in female rats

The effects of altering the number and type of additional carbohydrate moieties on the pharmacokinetic and pharmacodynamic properties of FSH were examined in this report. A series of single-chain follitropins, containing variable numbers of additional N- (or O-) linked carbohydrates, were designed and expressed in Chinese hamster ovary cells. Proper folding, efficient receptor binding, and signal transduction were confirmed by in vitro assays. Pharmacokinetic and pharmacodynamic parameters were evaluated in immature female Sprague Dawley rats. Increasing the number of glycosylation sites with either N- (or O-) linked moieties extended the elimination half-life as much as 2-fold compared with recombinant human FSH (rhFSH). However, there was a maximum elimination half-life such that further glycosylation provided no additional lengthening of the half-life. Conversely, biopotency, as assessed by inhibin A levels 74 h post injection, and follicle production were significantly higher for the N-linked analogs. Rats stimulated with the longest acting analogs (either N- or O-linked) showed significantly higher ovarian weights than rats receiving a single injection of rhFSH. The analog containing four additional N-linked sites (rhFSH-N4) had the greatest number of large, preovulatory follicles. Although the half-life of rhFSH-N4 displayed no further enhancement beyond the other longest acting analogs, this analog exhibited significantly increased biopotency in rats. This work provides the basis for the generation of a series of reagents potentially useful for therapeutic applications.

A rapid and systematic review and economic evaluation of the clinical and cost-effectiveness of newer drugs for treatment of mania associated with bipolar affective disorder

OBJECTIVES

To evaluate the clinical and cost-effectiveness of quetiapine, olanzapine and valproate semisodium in the treatment of mania associated with bipolar disorder.

DATA SOURCES

Electronic databases; industry submissions made to the National Institute for Clinical Excellence.

REVIEW METHODS

Randomised trials and economic evaluations that evaluated the effectiveness of quetiapine, olanzapine or valproate semisodium in the treatment of mania associated with bipolar disorder were selected for inclusion. Data were extracted by one reviewer into a Microsoft Access database and checked for quality and accuracy by a second. The quality of the cost-effectiveness studies was assessed using a checklist updated from that developed by Drummond and colleagues. Relative risk and mean difference data were presented as Forest plots but only pooled where this made sense clinically and statistically. Studies were grouped by drug and, within each drug, by comparator used. Chi-squared tests of heterogeneity were performed for the outcomes if pooling was indicated. A probabilistic model was developed to estimate costs from the perspective of the NHS, and health outcomes in terms of response rate, based on an improvement of at least 50% in a patient's baseline manic symptoms derived from an interview-based mania assessment scale. The model evaluated the cost-effectiveness of the alternative drugs when used as part of treatment for the acute manic episode only.

RESULTS

Eighteen randomised trials met the inclusion criteria. Aspects of three of the quetiapine studies were commercial-in-confidence. The quality of the included trials was limited and overall, key methodological criteria were not met in most trials. Quetiapine, olanzapine and valproate semisodium appear superior to placebo in reducing manic symptoms, but may cause side-effects. There appears to be little difference between these treatments and lithium in terms of effectiveness, but quetiapine is associated with somnolence and weight gain, whereas lithium is associated with tremor. Olanzapine as adjunct therapy to mood stabilisers may be more effective than placebo in reducing mania and improving global health, but it is associated with more dry mouth, somnolence, weight gain, increased appetite, tremor and speech disorder. There was little difference between these treatments and haloperidol in reducing mania, but haloperidol was associated with more extrapyramidal side-effects and negative implications for health-related quality of life. Intramuscular olanzapine and lorazepam were equally effective and safe in one very short (24 hour) trial. Valproate semisodium and carbamazepine were equally effective and safe in one small trial in children. Olanzapine may be more effective than valproate semisodium in reducing mania, but was associated with more dry mouth, increased appetite, oedema, somnolence, speech disorder, Parkinson-like symptoms and weight gain. Valproate semisodium was associated with more nausea than olanzapine. The results from the base-case analysis demonstrate that choice of optimal strategy is dependent on the maximum that the health service is prepared to pay per additional responder. For a figure of less than 7179 British pounds per additional responder, haloperidol is the optimal decision; for a spend in excess of this, it would be olanzapine. Under the most favourable scenario in relation to the costs of responders and non-responders beyond the 3-week period considered in the base-case analysis, the incremental cost-effectiveness ratio of olanzapine is reduced to 1236 British pounds.

CONCLUSIONS

In comparison with placebo, quetiapine, olanzapine and valproate semisodium appear superior in reducing manic symptoms, but all drugs are associated with adverse events. In comparison with lithium, no significant differences were found between the three drugs in terms of effectiveness, and all were associated with adverse events. Several limitations of the cost-effectiveness analysis exist, which inevitably means that the results should be treated with some caution. There remains a need for well-conducted, randomised, double-blind head-to-head comparisons of drugs used in the treatment of mania associated with bipolar disorder and their cost-effectiveness. Participant demographic, diagnostic characteristics, the treatment of mania in children, the use of adjunctive therapy and long-term safety issues in the elderly population, and acute and long-term treatment are also subjects for further study.

A pilot study on the use of decision theory and value of information analysis as part of the NHS Health Technology Assessment programme

OBJECTIVES

To demonstrate the benefits of using appropriate decision-analytic methods and value of information analysis (DA-VOI). Also to establish the feasibility and implications of applying these methods to inform the prioritisation process of the NHS Health Technology Assessment (HTA) programme, and possibly extending their use therein.

DATA SOURCES

Three research topics that were considered by the HTA panels in the September 2002 and February 2003 prioritisation rounds.

REVIEW METHODS

A brief and non-technical overview of DA-VOI methods was circulated to the panels and Prioritisation Strategy Group (PSG). For each case study the results were presented to the panels and the PSG in the form of brief case-study reports. Feedback on the DA-VOI analysis and its presentation was obtained in the form of completed questionnaires from panel members, and reports from panel senior lecturers and PSG members.

RESULTS

Although none of the research topics identified met all of the original selection criteria for inclusion as case studies in the pilot, it was possible to construct appropriate decision-analytic models and conduct probabilistic analysis for each topic. In each case, the tasks were completed within the time-frame required by the existing HTA research prioritisation process. The brief case-study reports provided a description of the decision problem, a summary of the current evidence base and a characterisation of decision uncertainty in the form of cost-effectiveness acceptability curves. Estimates of value of information for the decision problem were presented for relevant patient groups and clinical settings, as well as the value of information associated with particular model inputs. The implications for the value of research in each of the areas were presented in general terms. Details were also provided on what the analysis suggested regarding the design of any future research in terms of features such as the relevant patient groups and comparators, and whether experimental design was likely to be required.

CONCLUSIONS

The pilot study showed that, even with very short timelines, it is possible to undertake DA-VOI that can feed into the priority-setting process that has been developed for the HTA programme. There are however a number of areas that need to be established at the beginning of the process, such as clarification of the nature of the decision problem for which additional research is being considered, explicitness about which existing data should be used and how data that exhibit particular weaknesses should be down-weighted in the analysis. Other areas, including optimum application of researcher time, integrating the vignette (a summary of the clinical problem and existing evidence) and the use of DA-VOI, training, use of sensitivity analyses, and deployment of clinical expertise, are also considered in terms of the potential implementation of DA-VOI within the HTA programme. Recommendations for further research include how literature searching should focus on those variables to which the model's results are most sensitive and with the highest expected value of perfect information; methods of evidence synthesis (multiple parameter synthesis) to consider the evidence surrounding multiple comparators and networks of evidence; and ways in which the value of sample information can be used by the NHS HTA programme and other research funders to decide on the most efficient design of new evaluative research. There is also a need for an analytical framework to be developed that can jointly address the question of whether additional resources would better be devoted to additional research or interventions to change clinical practice.

A robust measure of HIV-1 population turnover within chronically infected individuals

A simple nonparameteric test for population structure was applied to temporally spaced samples of HIV-1 sequences from the gag-pol region within two chronically infected individuals. The results show that temporal structure can be detected for samples separated by about 22 months or more. The performance of the method, which was originally proposed to detect geographic structure, was tested for temporally spaced samples using neutral coalescent simulations. Simulations showed that the method is robust to variation in samples sizes and mutation rates, to the presence/absence of recombination, and that the power to detect temporal structure is high. By comparing levels of temporal structure in simulations to the levels observed in real data, we estimate the effective intra-individual population size of HIV-1 to be between 10(3) and 10(4) viruses, which is in agreement with some previous estimates. Using this estimate and a simple measure of sequence diversity, we estimate an effective neutral mutation rate of about 5 x 10(-6) per site per generation in the gag-pol region. The definition and interpretation of estimates of such "effective" population parameters are discussed.

Koch's bacillus - a look at the first isolate of Mycobacterium tuberculosis from a modern perspective

Using molecular methods the authors have studied mycobacterial DNA taken from a 19th century victim of tuberculosis. This was the case from which Robert Koch first isolated and cultured the organism responsible for tuberculosis. The mycobacteria were preserved within five glass culture tubes as abundant bacterial colonies on slopes of a gelatinous culture medium of unknown composition. Originally presented by Koch to surgical laryngologist Walter Jobson Horne in London in 1901, the relic has, since 1983, been in the care of the Royal College of Surgeons of England. Light and electron microscopy established the presence of acid-fast mycobacteria but showed that morphological preservation was generally poor. Eleven different genomic loci were successfully amplified by PCR. This series of experiments confirmed that the organisms were indeed Mycobacterium tuberculosis and further showed that the original strain was in evolutionary terms similar to 'modern' isolates, having undergone the TB D1 deletion. Attempts to determine the genotypic group of the isolate were only partially successful, due in part to the degraded nature of the DNA and possibly also to a truncation in the katG gene, which formed part of the classification scheme. Spoligotyping resulted in amplification of DR spacers consistent with M. tuberculosis but with discrepancies between independent extracts, stressing the limitations of this typing method when applied to poorly preserved material.

Choking deaths: the role of antipsychotic medication

BACKGROUND

An increased risk of choking associated with antipsychotic medication has been repeatedly postulated.

AIMS

To examine this association in a large number of cases of choking deaths.

METHOD

Cases of individuals who had died because of choking were linked with a case register recording contacts with public mental health services. The actual and expected rates of psychiatric disorder and the presence of psychotropic medication in post-mortem blood samples were compared.

RESULTS

The 70 people who had choked to death were over 20 times more likely to have been treated previously for schizophrenia. They were also more likely to have had a prior organic psychiatric syndrome. The risk for those receiving thioridazine or lithium was, respectively, 92 times and 30 times greater than expected. Other antipsychotic and psychotropic drugs were not over-represented.

CONCLUSIONS

The increased risk of death in people with schizophrenia may be a combination of inherent predispositions and the use of specific antipsychotic drugs. The increased risk of choking in those with organic psychiatric syndromes is consistent with the consequences of compromised neurological competence.