What is the clinical effectiveness and cost-effectiveness of using drugs in treating obese patients in primary care? A systematic review

BACKGROUND

Obesity [defined as a body mass index (BMI) ≥ 30 kg/m(2)] represents a considerable public health problem and is associated with a significant range of comorbidities and an increased mortality risk. The primary aim of the management of obesity is to achieve weight reduction in the interests of health. For obese patients who cannot achieve or maintain a healthy weight by non-pharmacological means, drug therapy is recommended in combination with non-pharmacological interventions such as dietary modifications and exercise.

OBJECTIVE

To evaluate the clinical effectiveness and cost-effectiveness of three pharmacological interventions in obese patients.

DATA SOURCES

Clinical effectiveness data used in the meta-analysis were sourced from articles identified in a systematic review of the literature. Data used to inform transitions to obesity-related comorbidities were derived from the General Practice Research Database (GPRD). The results of the meta-analysis and GPRD analyses informed the economic model supplemented by data from the Health Survey for England and other UK-specific data sourced from the literature.

REVIEW METHODS

A systematic literature review was conducted of the clinical effectiveness and cost-effectiveness of orlistat, sibutramine and rimonabant within their licensed indications for the treatment of obese patients. Electronic bibliographic databases including MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, The Cochrane Library databases and Cumulative Index to Nursing and Allied Health Literature (CINAHL) were searched in January 2009, and the reference lists of relevant articles were checked. Studies were included if they compared orlistat, sibutramine or rimonabant with lifestyle and/or exercise advice (standard care), placebo or metformin.

RESULTS

Overall, 94 studies involving 24,808 individuals were included in the clinical meta-analysis. Eighty-three trials included data on weight change, 41 included data on BMI change and 45 and 36 studies reported on 5% and 10% body weight loss, respectively. Overall, the results show that the active drug interventions are all effective at reducing weight and BMI compared with placebo. In the case of sibutramine, the higher dose (15 mg) resulted in a greater reduction than the lower dose (10 mg). Generally, the data quality of the trials included was low with poor reporting of standard errors and standard deviations. Results from the BMI risk models derived from the GPRD showed consistent increases in risk with increasing BMI. Adjustments for key confounders, such as age, sex and smoking status, were found to be statistically significant at the 5% level, in all risk models. Applying linear models to estimate BMI trajectories, for the diabetic cohort, an average increase in BMI of 0.040 per year for both men and women was observed. The non-diabetic cohort model showed an increase in BMI of 0.175 per year for women and 0.145 per year for men. The results of the cost-effectiveness analyses suggest that sibutramine 15 mg dominates the other three active interventions and the net benefit analyses show that sibutramine 15 mg is the most cost-effective alternative for thresholds > £2000 per quality-adjusted life-year (QALY). However, both sibutramine and rimonabant have been withdrawn because of safety concerns relating to potential treatment-induced fatal adverse events. If the proportion of patients who experienced a fatal adverse event was > 1.8% (1.5%, 1.0%) for sibutramine 15 mg (sibutramine 10 mg, rimonabant) the treatment would not be considered cost-effective when using a threshold of £20,000 per QALY.

LIMITATIONS

The clinical review did not include all possible lifestyle comparators, with the inclusion limited to only those trials included one of the active drug interventions. We also excluded all studies not reported in English. Although the clinical review included data from 94 studies, the quality of data was generally low, particularly in terms of the reporting of standard deviation. There was also inconsistency between the results of the mixed-treatment comparison (MTC) and the pair-wise analyses.

CONCLUSION

The MTC of anti-obesity treatments shows that all the active treatments are effective at reducing weight and BMI. The economic results show that, compared with placebo, the treatments are all cost-effective when using a threshold of £20,000 per QALY, and, within the limitations of the data available, sibutramine 15 mg dominates the other three interventions. This work has highlighted many areas of methodological research that could be explored, including assessing inconsistencies within a network to determine differences between the results of pair-wise and MTC analyses; the use of meta-regression methods to look for effect modifiers; exploring the effect of local publication bias; and the use of joint models to analyse the repeated measures of BMI and the time-to-event processes simultaneously.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Diagnostic management strategies for adults and children with minor head injury: a systematic review and an economic evaluation

BACKGROUND

Patients with minor head injury [Glasgow Coma Scale (GCS) score 13-15] have a small but important risk of intracranial injury (ICI) that requires early identification and neurosurgical treatment. Diagnostic assessment can use either a clinical decision rule or unstructured assessment of individual clinical features to identify those who are at risk of ICI and in need of computerised tomography (CT) scanning and/or hospital admission. Selective use of CT investigations helps minimise unnecessary radiation exposure and resource use, but can lead to missed opportunities to provide early treatment for ICI.

OBJECTIVES

To determine the diagnostic accuracy of decision rules, individual clinical characteristics, skull radiography and biomarkers, and the clinical effectiveness and cost-effectiveness of diagnostic management strategies for minor head injury (MHI).

DATA SOURCES

Several electronic databases [including MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, Cumulative Index to Nursing and Allied Health Literature (CINAHL), EMBASE and The Cochrane Library] were searched from inception to April 2009 (updated searches to March 2010 were conducted on the MEDLINE databases only). Searches were supplemented by hand-searching relevant articles (including citation searching) and contacting experts in the field. For each of the systematic reviews the following studies were included (1) cohort studies of patients with MHI in which a clinical decision rule or individual clinical characteristics (including biomarkers and skull radiography) were compared with a reference standard test for ICI or need for neurosurgical intervention and (2) controlled trials comparing alternative management strategies for MHI.

REVIEW METHODS

Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool (for the assessment of diagnostic accuracy) or criteria recommended by the Effective Practice and Organisation of Care Review Group (for the assessment of management practices). Where sufficient data existed, a meta-analysis was undertaken to generate pooled estimates of diagnostic parameters. A decision-analysis model was developed using Simul8 2008 Professional software (Simul8 Corporation, Boston, MA, USA) to estimate the costs and quality-adjusted life-years (QALYs) accrued by management strategies for MHI. The model took a lifetime horizon and NHS perspective. Estimates of the benefits of early treatment, harm of radiation exposure and long-term costs were obtained through literature reviews. Initial analysis was deterministic, but probabilistic sensitivity analysis was also performed. Secondary analyses were undertaken to explore the trade-off between sensitivity and specificity in diagnostic strategies and to determine the cost-effectiveness of scenarios involving hospital admission.

RESULTS

The literature searches identified 8003 citations. Of these, 93 full-text papers were included for the assessment of diagnostic accuracy and one for the assessment of management practices. The quality of studies and reporting was generally poor. The Canadian CT Head Rule (CCHR) was the most widely validated adult rule, with sensitivity of 99-100% and 80-100% for neurosurgical and any ICI, respectively (high- or medium-risk criteria), and specificity of 39-51%. Rules for children had high sensitivity and acceptable specificity in derivation cohorts, but limited validation. Depressed, basal or radiological skull fracture and post-traumatic seizure (PTS) [positive likelihood ratio (PLR) > 10]; focal neurological deficit, persistent vomiting, decrease in GCS and previous neurosurgery (PLR 5-10); and fall from a height, coagulopathy, chronic alcohol use, age > 60 years, pedestrian motor vehicle accident (MVA), any seizure, undefined vomiting, amnesia, GCS < 14 and GCS < 15 (PLR 2-5) increased the likelihood of ICI in adults. Depressed or basal skull fracture and focal neurological deficit (PLR > 10), coagulopathy, PTS and previous neurosurgery (PLR 5-10), visual symptoms, bicycle and pedestrian MVA, any seizure, loss of consciousness, vomiting, severe or persistent headache, amnesia, GCS < 14, GCS < 15, intoxication and radiological skull fracture (PLR 2-5) increased the likelihood of ICI in children. S100 calcium-binding protein B had pooled sensitivity of 96.8% [95% highest-density region (HDR) 93.8% to 98.6%] and specificity of 42.5% (95% HDR 31.0% to 54.2%). The only controlled trial showed that early CT and discharge is cheaper and at least as effective as hospital admission. Economic analysis showed that selective CT use dominated 'CT all' and 'discharge all' strategies. The optimal strategies were the CCHR (adults) and the CHALICE (Children's Head injury Algorithm for the prediction of Important Clinical Events) or NEXUS II (National Emergency X-Radiography Utilization Study II) rule (children). The sensitivity and specificity of the CCHR (99% and 47%, respectively) represented an appropriate trade-off of these parameters. Hospital admission dominated discharge home for patients with non-neurosurgical injury, but cost £39 M per QALY for clinically normal patients with a normal CT.

CONCLUSIONS

The CCHR is widely validated and cost-effective for adults. Decision rules for children appear cost-effective, but need further validation. Hospital admission is cost-effective for patients with abnormal, but not normal, CT. The main research priorities are to (1) validate decision rules for children; (2) determine the prognosis and treatment benefit for non-neurosurgical injuries; (3) evaluate the use of S100B alongside a validated decision rule; (4) evaluate the diagnosis and outcomes of anticoagulated patients with MHI; and (5) evaluate the implementation of guidelines, clinical decision rules and diagnostic strategies. Formal expected value of sample information analysis would be recommended to appraise the cost-effectiveness of future studies.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

The clinical effectiveness and safety of prophylactic retinal interventions to reduce the risk of retinal detachment and subsequent vision loss in adults and children with Stickler syndrome: a systematic review

BACKGROUND

Stickler syndrome, also known as hereditary progressive arthro-ophthalmopathy, is an inherited progressive disorder of the collagen connective tissues. Manifestations include short-sightedness, cataracts, retinal problems leading to retinal detachment and possible blindness. This is principally the case among individuals with type 1 Stickler Syndrome. It is the most commonly identified inherited cause of retinal detachment in childhood. However, there is no consensus regarding best practice and no current guidelines on prophylactic interventions for this population.

OBJECTIVES

The aim of this systematic review was to assess the evidence for the clinical effectiveness and safety of primary prophylactic interventions for the prevention of retinal detachment in previously untreated eyes without retinal detachment in patients with Stickler syndrome. The primary outcome of interest was retinal detachment post prophylaxis.

DATA SOURCES

A systematic search was made of 11 databases of published and unpublished literature, which included MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, the Cumulative Index to Nursing and Allied Health Literature and The Cochrane Library. There was no restriction by language or date. The references of all included studies were checked for further relevant citations and authors of studies with potentially relevant data were also contacted.

REVIEW METHODS

Two reviewers double-screened all titles and abstracts of the citations retrieved by the search to identify studies that satisfied the inclusion criteria. Both reviewers also independently extracted and quality assessed all included studies. A narrative synthesis was performed.

RESULTS

The literature search identified 1444 unique citations, of which four studies satisfied the inclusion criteria. The two principal studies were both retrospective cohort studies with control groups in populations with type 1 Stickler syndrome. One study evaluated 360° cryotherapy (n = 204) and the other focal or circumferential laser treatment (n = 22). Both studies reported a statistically significant difference in the rate of retinal detachment per eye between the groups receiving prophylaxis and the controls. However, both studies were subject to a high risk of bias. The results of the two supporting studies of Wagner-Stickler patients were either relatively inconsistent or unreliable. No study reported any major or long-term complications associated with the interventions. Despite the weaknesses of the evidence, the rate of retinal detachment in the intervention groups, especially the cryotherapy group, was lower than the rate either experienced in the study control groups or reported in other studies of untreated Stickler syndrome populations not exposed to prophylaxis.

CONCLUSIONS

Only 360° cryotherapy and focal and circumferential laser treatment have been evaluated for the type 1 Stickler syndrome population, and then only by a single retrospective, controlled, cohort study in each case. Both of these studies report a significant difference between intervention and control groups (principally no treatment) and no major or long-term side effects or complications. However, there is a high risk of bias within these two studies, so the relative effectiveness of either intervention is uncertain.

FUTURE WORK

A service priority is to determine reliably the prevalence of Stickler syndrome, i.e. how many individuals have type 1 or type 2 Stickler syndrome, and their risk of retinal detachment and subsequent blindness. A non-randomised, prospective cohort comparison study, in which eligible participants are treated, followed-up and analysed in one of three study arms, for no treatment, laser therapy or cryotherapy, would potentially offer further certainty in terms of the relative efficacy of both prophylaxis versus no prophylaxis and cryotherapy versus laser therapy than is possible with the currently available data. Alternatively, continued follow-up and analysis of existing study data, and data collection from relevant sample populations, are required to assess the long-term risks of blindness, retinal detachment and prophylaxis.

FUNDING

This study was funded by the National Institute for Health Research Health Technology Assessment programme.

Prescribing high-dose lipid-lowering therapy early to avoid subsequent cardiovascular events: is this a cost-effective strategy?

BACKGROUND

While evidence shows high-dose statins reduce cardiovascular events compared with moderate doses in individuals with acute coronary syndrome (ACS), many primary care trusts (PCT) advocate the use of generic simvastatin 40 mg/day for these patients.

METHODS AND RESULTS

Data from 28 RCTs were synthesized using a mixed treatment comparison model. A Markov model was used to evaluate the cost-effectiveness of treatments taking into account adherence and the likely reduction in cost for atorvastatin when the patent expires. There is a clear dose-response: rosuvastatin 40 mg/day produces the greatest reduction in low-density lipoprotein cholesterol (56%) followed by atorvastatin 80 mg/day (52%), and simvastatin 40 mg/day (37%). Using a threshold of £20,000 per QALY, if adherence levels in general practice are similar to those observed in RCTs, all three higher dose statins would be considered cost-effective compared to simvastatin 40 mg/day. Using the net benefits of the treatments, rosuvastatin 40 mg/day is estimated to be the most cost-effective alternative. If the cost of atorvastatin reduces in line with that observed for simvastatin, atorvastatin 80 mg/day is estimated to be the most cost-effective alternative.

CONCLUSION

Our analyses show that current PCT policies intended to minimize primary care drug acquisition costs result in suboptimal care.

Bevacizumab in combination with fluoropyrimidine-based chemotherapy for the first-line treatment of metastatic colorectal cancer

This paper presents a summary of the evidence review group (ERG) report into the clinical effectiveness and cost-effectiveness of bevacizumab in combination with fluoropyrimidine-based chemotherapy for the first-line treatment of metastatic colorectal cancer based on the manufacturer's submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. Evidence was available in the form of one phase III, multicentre, multinational, randomised, open-label study (NO16966 trial). This two-arm study was originally designed to demonstrate the non-inferiority of oral capecitabine plus oxaliplatin (XELOX) compared with 5-fluorouracil plus folinic acid plus oxaliplatin (FOLFOX)-4 in adult patients with histologically confirmed metastatic colorectal cancer who had not previously been treated. Following randomisation of 634 patients, the open-label study was amended to include a 2 × 2 factorial randomised (partially blinded for bevacizumab) phase III trial with the coprimary objective of demonstrating superiority of bevacizumab in combination with chemotherapy compared with chemotherapy alone. Measured outcomes included overall survival, progression-free survival, response rate, adverse effects of treatment and health-related quality of life. The manufacturer's primary pooled analysis of superiority (using the intention-to-treat population) showed that after a median follow-up of 28 months, the addition of bevacizumab to chemotherapy significantly improved progression-free survival and overall survival compared with chemotherapy alone in adult patients with histologically confirmed metastatic colorectal cancer who were not previously treated [median progression-free survival 9.4 vs 7.7 months (absolute difference 1.7 months); hazard ratio (HR) 0.79, 97.5% confidence interval (CI) 0.72 to 0.87; p = 0.0001; median overall survival 21.2 vs 18.9 months (absolute difference 2.3 months); HR 0.83, 97.5% CI 0.74 to 0.93; p = 0.0019]. The NO16966 trial was of reasonable methodological quality and demonstrated a significant improvement in both progression-free survival and overall survival when bevacizumab was added to XELOX or FOLFOX. However, the size of the actual treatment effect of bevacizumab is uncertain. The ERG believed that the modelling structure employed was appropriate, but highlighted several key issues and areas of uncertainty. At the time of writing, NICE was yet to issue the guidance for this appraisal.

Intensity-modulated radiotherapy for the treatment of prostate cancer: a systematic review and economic evaluation

BACKGROUND

Prostate cancer (PC) is the most common cancer in men in the UK. Radiotherapy (RT) is a recognised treatment for PC and high-dose conformal radiotherapy (CRT) is the recommended standard of care for localised or locally advanced tumours. Intensity-modulated radiotherapy (IMRT) allows better dose distributions in RT.

OBJECTIVE

This report evaluates the clinical effectiveness and cost-effectiveness of IMRT for the radical treatment of PC.

DATA SOURCES

The following databases were searched: MEDLINE (1950-present), EMBASE (1980-present), Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982-present), BIOSIS (1985-present), the Cochrane Database of Systematic Reviews (1991-present), the Cochrane Controlled Trials Register (1991-present), the Science Citation Index (1900-present) and the NHS Centre for Reviews and Dissemination databases (Database of Abstracts of Reviews of Effects, NHS Economic Evaluation Database, Health Technology Assessment) (1991-present). MEDLINE In-Process & Other Non-Indexed Citations was searched to identify any studies not yet indexed on MEDLINE. Current research was identified through searching the UK Clinical Research Network, National Research Register archive, the Current Controlled Trials register and the Medical Research Council Clinical Trials Register. In addition, abstracts of the American Society of Clinical Oncology, the American Society for Therapeutic Radiology and Oncology, and European Society for Therapeutic Radiology and Oncology conferences were browsed.

REVIEW METHODS

A systematic literature review of the clinical effectiveness and cost-effectiveness of IMRT in PC was conducted. Comparators were three-dimensional conformal radiotherapy (3DCRT) or radical prostatectomy. Outcomes sought were overall survival, biochemical [prostate-specific antigen (PSA)] relapse-free survival, toxicity and health-related quality of life (HRQoL). Fifteen electronic bibliographic databases were searched in January 2009 and updated in May 2009, and the reference lists of relevant articles were checked. Studies only published in languages other than English were excluded. An economic model was developed to examine the cost-effectiveness of IMRT in comparison to 3DCRT. Four scenarios were modelled based on the studies which reported both PSA survival and late gastrointestinal (GI) toxicity. In two scenarios equal PSA survival was assumed for IMRT and 3DCRT, the other two having greater PSA survival for the IMRT cohort. As there was very limited data on clinical outcomes, the model estimates progression to clinical failure and PC death from the surrogate outcome of PSA failure.

RESULTS

No randomised controlled trials (RCTs) of IMRT versus 3DCRT in PC were available, but 13 non-randomised studies comparing IMRT with 3DCRT were found, of which five were available only as abstracts. One abstract reported overall survival. Biochemical relapse-free survival was not affected by treatment group, except where there was a dose difference between groups, in which case higher dose IMRT was favoured over lower dose 3DCRT. Most studies reported an advantage for IMRT in GI toxicity, attributed to increased conformality of treatment compared with 3DCRT, particularly with regard to volume of rectum treated. There was some indication that genitourinary toxicity was worse for patients treated with dose escalated IMRT, although most studies did not find a significant treatment effect. HRQoL improved for both treatment groups following radiotherapy, with any group difference resolved by 6 months after treatment. No comparative studies of IMRT versus prostatectomy were identified. No comparative studies of IMRT in PC patients with bone metastasis were identified.

LIMITATIONS

The strength of the conclusions of this review are limited by the lack of RCTs, and any comparative studies for some patient groups.

CONCLUSIONS

The comparative data of IMRT versus 3DCRT seem to support the theory that higher doses, up to 81 Gy, can improve biochemical survival for patients with localised PC, concurring with data on CRT. The data also suggest that toxicity can be reduced by increasing conformality of treatment, particularly with regard to GI toxicity, which can be more easily achieved with IMRT than 3DCRT. Whether differences in GI toxicity between IMRT and 3DCRT are sufficient for IMRT to be cost-effective is uncertain, depending on the difference in incidence of GI toxicity, its duration and the cost difference between IMRT and 3DCRT.

Bevacizumab in combination with fluoropyrimidine-based chemotherapy for the first-line treatment of metastatic colorectal cancer

This paper presents a summary of the evidence review group (ERG) report into the clinical effectiveness and cost-effectiveness of bevacizumab in combination with fluoropyrimidine-based chemotherapy for the first-line treatment of metastatic colorectal cancer based on the manufacturer’s submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. Evidence was available in the form of one phase III, multicentre, multinational, randomised, open-label study (NO16966 trial). This two-arm study was originally designed to demonstrate the non-inferiority of oral capecitabine plus oxaliplatin (XELOX) compared with 5-fluorouracil plus folinic acid plus oxaliplatin (FOLFOX)-4 in adult patients with histologically confirmed metastatic colorectal cancer who had not previously been treated. Following randomisation of 634 patients, the open-label study was amended to include a 2 × 2 factorial randomised (partially blinded for bevacizumab) phase III trial with the coprimary objective of demonstrating superiority of bevacizumab in combination with chemotherapy compared with chemotherapy alone. Measured outcomes included overall survival, progression-free survival, response rate, adverse effects of treatment and health-related quality of life. The manufacturer’s primary pooled analysis of superiority (using the intention-to-treat population) showed that after a median follow-up of 28 months, the addition of bevacizumab to chemotherapy significantly improved progression-free survival and overall survival compared with chemotherapy alone in adult patients with histologically confirmed metastatic colorectal cancer who were not previously treated [median progression-free survival 9.4 vs 7.7 months (absolute difference 1.7 months); hazard ratio (HR) 0.79, 97.5% confidence interval (CI) 0.72 to 0.87; p = 0.0001; median overall survival 21.2 vs 18.9 months (absolute difference 2.3 months); HR 0.83, 97.5% CI 0.74 to 0.93; p = 0.0019]. The NO16966 trial was of reasonable methodological quality and demonstrated a significant improvement in both progression-free survival and overall survival when bevacizumab was added to XELOX or FOLFOX. However, the size of the actual treatment effect of bevacizumab is uncertain. The ERG believed that the modelling structure employed was appropriate, but highlighted several key issues and areas of uncertainty. At the time of writing, NICE was yet to issue the guidance for this appraisal.

Repeated measurements of 11β-HSD-1 activity in subcutaneous adipose tissue from lean, abdominally obese, and type 2 diabetes subjects--no change following a mixed meal

The aim of this study was to measure 11β-HSD-1 activity in subcutaneous adipose tissue by an ex vivo method in three subgroups; lean, obese, and type 2 diabetes subjects, both in the fasting state and after a mixed meal and to determine the variability and reproducibility of this method. Eighteen subjects were investigated; 6 lean, 6 abdominally obese, and 6 type 2 diabetes subjects (BMI 22 ± 1, 30 ± 3 and 31 ± 3 kg/m², respectively). Needle biopsies were taken repeatedly and an index of 11β-HSD-1 activity was measured as percent conversion of (3)H-cortisone to (3)H-cortisol/100 mg tissue. For two separate biopsies taken in the fasting state on the same day, the within subjects CV was 16% and the between CV was 36% for 11β-HSD-1 activity for all subjects. For two biopsies taken in the fasting state at two different days, the total within subjects CV was 38% and the between subjects CV was 46%. Lean subjects had lower 11β-HSD-1 activity (4.8 ± 1.5% conversion of ³H-cortisone to ³H-cortisol/100 mg tissue) than both obese (14.4 ± 1.6% conversion, p<0.01) and type 2 diabetes subjects (11.7 ± 1.9% conversion, p<0.05) in the fasting state. There was no effect of a meal on 11β-HSD-1 activity in any of the three groups. The conclusions from this study are: 1) the variation coefficient for the ex vivo adipose tissue 11β-HSD-1 activity method was ∼25% for repeat measures within subjects; 2) food intake had no major impact on enzyme activity; and 3) 11β-HSD-1 activity in subcutaneous adipose tissue was significantly increased in obese subjects with or without T2DM compared to lean subjects without diabetes.

Rivaroxaban for the prevention of venous thromboembolism: a single technology appraisal

This paper presents a summary of the evidence review group (ERG) report into the clinical effectiveness and cost-effectiveness of rivaroxaban for the prevention of venous thromboembolism (VTE) in adult patients undergoing elective hip or knee replacement surgery based upon a review of the manufacturer's submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The submission's evidence came from four randomised controlled trials (RCTs) comparing rivaroxaban with enoxaparin [RECORD (Regulation of Coagulation in Orthopedic surgery to pRevent Deep venous thrombosis and pulmonary embolism) 1-4] and three comparing dabigatran with enoxaparin [RE-NOVATE (the prevention of venous thromboembolism after total hip replacement trial), RE-MODEL (the prevention of venous thromboembolism after total knee replacement trial) and RE-MOBILIZE (the prevention of venous thromboembolism after total knee arthroplasty trial)]. The evidence from the four RECORD trials indicates that rivaroxaban had superior efficacy over enoxaparin after total hip replacement (THR) and total knee replacement (TKR). For the composite primary outcome of any deep vein thrombosis (DVT), non-fatal pulmonary embolism (PE) and death from all causes the relative risk reductions were 70-79% in THR and 31-49% in TKR. Rivaroxaban also had superior efficacy over enoxaparin for the secondary outcome major VTE. Rivaroxaban was not inferior to enoxaparin on the safety outcome of major bleeding. After the correction of some errors found by the ERG, the manufacturer's economic model represented a reasonable model of patients receiving prophylaxis for THR or TKR. In the base-case analyses rivaroxaban dominated both enoxaparin and dabigatran. The incremental costs saved and quality-adjusted life-years (QALYs) gained were small (below 200 pounds and 0.005, respectively, per person). Analyses were conducted sampling from the distributions observed from the RCTs. When all parameters were sampled rivaroxaban dominated enoxaparin in all scenarios except for two, in which enoxaparin produced more QALYs than rivaroxaban and had an incremental cost per QALY gained of 5000 pounds and 8000 pounds respectively. Rivaroxaban dominated dabigatran when RECORD 1 and RECORD 2, individually or pooled, were compared with RE-NOVATE and when all four rivaroxaban RCTs pooled were compared with all three dabigatran RCTs. Dabigatran dominated rivaroxaban comparing RECORD 4 with RE-MODEL and RE-MOBILIZE, and was more cost-effective than rivaroxaban comparing RECORD 3 (incremental cost per QALY gained of rivaroxaban compared with dabigatran of 123,000 pounds) or RECORD 3 and RECORD 4 pooled (incremental cost per QALY gained of dabigatran compared with rivaroxaban of 400 pounds) with RE-MODEL and RE-MOBILIZE. In conclusion, the evidence indicates that rivaroxaban is not inferior to enoxaparin in terms of the primary and secondary outcomes. The submission presents a reasonable estimation of the cost-effectiveness of rivaroxaban compared with enoxaparin and dabigatran, although the uncertainty in the decision has been underestimated. The results are particularly sensitive to any assumed difference in the number of fatal PEs, but the ERG does not believe there is sufficient evidence to support a difference between interventions. The NICE guidance issued as a result of the STA states that: riveroxaban, within its marketing authorisation, is recommended as an option for the prevention of venous thromboembolism in adults having elective THR or elective TKB.

Early high-dose lipid-lowering therapy to avoid cardiac events: a systematic review and economic evaluation

OBJECTIVE

To evaluate the cost-effectiveness of high-dose statins (atorvastatin 80 mg/day, rosuvastatin 40 mg/day and simvastatin 80 mg/day) versus simvastatin 40 mg/day in individuals with acute coronary syndrome (ACS).

DATA SOURCES

Eleven bibliographic databases, including MEDLINE, CINAHL, EMBASE, Cochrane Database of Systematic Reviews, CENTRAL, DARE and NHS EED, were searched from inception to 2008.

REVIEW METHODS

Data relating to study design, baseline patient characteristics, clinical or surrogate outcome, and adverse events were abstracted, and methodological quality was assessed according to standard methods. A synthesis of the available evidence was performed using a Bayesian mixed treatment meta-analysis using both direct and indirect evidence. An existing Markov model was modified to explore the costs and benefits associated with a lifetime of the differing treatment regimens.

RESULTS

A total of 3345 titles and abstracts were screened for inclusion in the review of clinical effectiveness and 125 full papers retrieved and assessed in detail. Of these, 30 papers met the inclusion criteria for the review, describing 28 trials. The Bayesian mixed treatment meta-analysis demonstrated a clear dose-response relationship in terms of reductions in low-density lipoprotein cholesterol (LDL-c), with rosuvastatin 40 mg/day achieving the greatest percentage reduction (56%) from baseline, followed by atorvastatin 80 mg/day (52%), simvastatin 80 mg/day (45%) and simvastatin 40 mg/day (37%). Although serious adverse events with statins are rare, their incidence is likely to be greater with higher doses. Several clinical scenarios were used to explore the effect of adherence on the cost-effectiveness of the treatment regimens. Using a threshold of 20,000 pounds per quality-adjusted life-year (QALY) and assuming that the benefits and adherence rates observed in the clinical trials are generalisable to a clinical setting and that individuals who do not tolerate the higher-dose statins are prescribed simvastatin 40 mg/day, then simvastatin 80 mg/day, atorvastatin 80 mg/day and rosuvastatin 40 mg/day would be considered cost-effective compared with simvastatin 40 mg/day in individuals with ACS. Simvastatin 80 mg/day is not well tolerated because of the high incidence rates of less severe adverse events such as myopathy (26-fold higher than rates in those receiving simvastatin 20 mg/day), which are likely to affect adherence levels in clinical practice. The reference case shows that rosuvastatin is the optimal treatment for individuals with a recent history of ACS using a threshold of 20,000 pounds per QALY. However, this is based on the assumption that the additional incremental reductions in LDL-c observed in patients treated with rosuvastatin 40 mg/day compared with atorvastatin will transfer into corresponding changes in relative risks of cardiovascular events.

CONCLUSIONS

Simvastatin 80 mg/day cannot be recommended because of the high incidence rates of adverse events. If the cost of atorvastatin decreases in line with that observed for simvastatin when the patent ends in 2011, atorvastatin 80 mg/day will be the most cost-effective treatment for all thresholds; if the cost reduces to 25% of the current value, atorvastatin 80 mg/day will be the most cost-effective treatment for thresholds between 5000 pounds and 30,000 pounds per QALY. Large long-term RCTs reporting effects in terms of clinical events are required to determine the optimum statin use for subgroups.

Rivaroxaban for the prevention of venous thromboembolism: a single technology appraisal

This paper presents a summary of the evidence review group (ERG) report into the clinical effectiveness and cost-effectiveness of rivaroxaban for the prevention of venous thromboembolism (VTE) in adult patients undergoing elective hip or knee replacement surgery based upon a review of the manufacturer’s submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The submission’s evidence came from four randomised controlled trials (RCTs) comparing rivaroxaban with enoxaparin [RECORD (Regulation of Coagulation in Orthopedic surgery to pRevent Deep venous thrombosis and pulmonary embolism) 1–4] and three comparing dabigatran with enoxaparin [RE-NOVATE (the prevention of venous thromboembolism after total hip replacement trial), RE-MODEL (the prevention of venous thromboembolism after total knee replacement trial) and RE-MOBILIZE (the prevention of venous thromboembolism after total knee arthroplasty trial)]. The evidence from the four RECORD trials indicates that rivaroxaban had superior efficacy over enoxaparin after total hip replacement (THR) and total knee replacement (TKR). For the composite primary outcome of any deep vein thrombosis (DVT), non-fatal pulmonary embolism (PE) and death from all causes the relative risk reductions were 70–79% in THR and 31–49% in TKR. Rivaroxaban also had superior efficacy over enoxaparin for the secondary outcome major VTE. Rivaroxaban was not inferior to enoxaparin on the safety outcome of major bleeding. After the correction of some errors found by the ERG, the manufacturer’s economic model represented a reasonable model of patients receiving prophylaxis for THR or TKR. In the base-case analyses rivaroxaban dominated both enoxaparin and dabigatran. The incremental costs saved and quality-adjusted life-years (QALYs) gained were small (below £200 and 0.005, respectively, per person). Analyses were conducted sampling from the distributions observed from the RCTs. When all parameters were sampled rivaroxaban dominated enoxaparin in all scenarios except for two, in which enoxaparin produced more QALYs than rivaroxaban and had an incremental cost per QALY gained of £5000 and £8000 respectively. Rivaroxaban dominated dabigatran when RECORD 1 and RECORD 2, individually or pooled, were compared with RE-NOVATE and when all four rivaroxaban RCTs pooled were compared with all three dabigatran RCTs. Dabigatran dominated rivaroxaban comparing RECORD 4 with RE-MODEL and RE-MOBILIZE, and was more cost-effective than rivaroxaban comparing RECORD 3 (incremental cost per QALY gained of rivaroxaban compared with dabigatran of £123,000) or RECORD 3 and RECORD 4 pooled (incremental cost per QALY gained of dabigatran compared with rivaroxaban of £400) with RE-MODEL and RE-MOBILIZE. In conclusion, the evidence indicates that rivaroxaban is not inferior to enoxaparin in terms of the primary and secondary outcomes. The submission presents a reasonable estimation of the cost-effectiveness of rivaroxaban compared with enoxaparin and dabigatran, although the uncertainty in the decision has been underestimated. The results are particularly sensitive to any assumed difference in the number of fatal PEs, but the ERG does not believe there is sufficient evidence to support a difference between interventions. The NICE guidance issued as a result of the STA states that: riveroxaban, within its marketing authorisation, is recommended as an option for the prevention of venous thromboembolism in adults having elective THR or elective TKB.

Routine antenatal anti-D prophylaxis for RhD-negative women: a systematic review and economic evaluation

OBJECTIVES

To identify any evidence for advances in the use of routine antenatal anti-D prophylaxis (RAADP) since the 2002 National Institute for Health and Clinical Excellence (NICE) appraisal, and to assess the current clinical effectiveness and cost-effectiveness of RAADP for Rhesus D (RhD)-negative women.

DATA SOURCES

Main bibliographic databases were searched from inception to July 2007.

REVIEW METHODS

Selected studies were assessed and data extracted using a standard template and quality assessment based on published criteria. Meta-analysis was used where appropriate, otherwise outcomes were tabulated and discussed within a descriptive synthesis. The health economic model developed for the 2002 NICE appraisal of RAADP was modified to assess the cost-effectiveness of different regimens of RAADP.

RESULTS

The clinical effectiveness searches identified 670 potentially relevant articles. Of these, 12 papers were included in the review, relating to eight studies of clinical effectiveness. With one exception, no additional studies were identified in comparison with the previous assessment report, and some of the studies of clinical effectiveness included in the 2002 review had to be excluded because they did not use currently licensed doses. Therefore, eight studies comparing RAADP with no prophylaxis were identified in the clinical effectiveness review and nine (including the 2001 assessment report itself) in the cost-effectiveness review. The clinical efficacy studies were generally of poor quality and did not provide a basis for differentiating between regimens of RAADP. The best indication of the likely efficacy of a programme of RAADP comes from two non-randomised community-based studies. The pooled results of these suggest that such a programme may reduce the sensitisation rate from 0.95% (95% CI 0.18-1.71) to 0.35% (95% CI 0.29-0.40). This gives an odds ratio for the risk of sensitisation of 0.37 (95% CI 0.21-0.65) and an absolute reduction in risk of sensitisation in RhD-negative mothers at risk (i.e. carrying a RhD-positive child) of 0.6%. The identified studies suggest that RAADP has minimal adverse effects. Of the nine studies in the cost-effectiveness review, only two described a model that could be applicable to the NHS. The economic model modified from the 2002 appraisal suggests that the cost per quality-adjusted life-year (QALY) gained of RAADP given to RhD-negative primigravidae versus no treatment is between 9000 pounds and 15,000 pounds, and for RAADP given to all RhD-negative women rather than to RhD-negative primigravidae only is between 20,000 pounds and 35,000 pounds depending upon the regimen. The sensitivity analysis suggests that the results are reasonably robust to changes in the assumptions within the model.

CONCLUSIONS

RAADP reduces the incidence of sensitisation and hence of haemolytic disease of the newborn. The economic model suggests that RAADP given to all RhD-negative pregnant women is likely to be cost-effective at a threshold of around 30,000 pounds per QALY gained. The total cost of providing RAADP to RhD-negative primigravidae in England and Wales is estimated to be around 1.8-3.1 million pounds per year, depending upon regimen, and to all RhD-negative pregnant women in England and Wales around 2-3.5 million pounds.

Amantadine, oseltamivir and zanamivir for the prophylaxis of influenza (including a review of existing guidance no. 67): a systematic review and economic evaluation

OBJECTIVES

To evaluate the clinical effectiveness and incremental cost-effectiveness of amantadine, oseltamivir and zanamivir for seasonal and post-exposure prophylaxis of influenza.

DATA SOURCES

A MEDLINE search strategy was used and searches were carried out in July 2007.

REVIEW METHODS

An independent health economic model was developed based on a review of existing cost-effectiveness models and clinical advice.The model draws together a broad spectrum of evidence relating to the costs and consequences associated with influenza and its prevention. Where direct evidence concerning the effectiveness of prophylaxis within specific model subgroups was lacking, the model uses estimates from mixed subgroups or extrapolates from other mutually exclusive subgroups.

RESULTS

Twenty-six published references relating to 22 randomised controlled trials (RCTs) were included in the clinical effectiveness review, along with one unpublished report. Eight, six and nine RCTs were included for amantadine, oseltamivir and zanamivir respectively. The study quality was variable and gaps in the evidence base limited the assessment of the clinical effectiveness of the interventions. For seasonal prophylaxis, there was limited evidence for the efficacy of amantadine in preventing symptomatic, laboratory-confirmed influenza (SLCI) in healthy adults [relative risk (RR) 0.40, 95% confidence interval (CI) 0.08-2.03]. Oseltamivir was effective in preventing SLCI, particularly when used in at-risk elderly subjects (RR 0.08, 95% CI 0.01-0.63). The preventative efficacy of zanamivir was most notable in at-risk adults and adolescents (RR 0.17, 95% CI 0.07-0.44), and healthy and at-risk elderly subjects (RR 0.20, 95% CI 0.02-1.72). For post-exposure prophylaxis, data on the use of amantadine were again limited: in adolescents an RR of 0.10 (95% CI 0.03-0.34) was reported for the prevention of SLCI. Oseltamivir was effective in households of mixed composition (RR 0.19, 95% CI 0.08-0.45). The efficacy of zanamivir in post-exposure prophylaxis within households was also reported (RR 0.21, 95% CI 0.13-0.33). Interventions appeared to be well tolerated. Limited evidence was available for the effectiveness of the interventions in preventing complications and hospitalisation and in minimising length of illness and time to return to normal activities. No clinical effectiveness data were identified for health-related quality of life or mortality outcomes. With the exception of at-risk children, the incremental cost-utility of seasonal influenza prophylaxis is expected to be in the range 38,000-428,000 pounds per QALY gained (depending on subgroup). The cost-effectiveness ratios for oseltamivir and zanamivir as post-exposure prophylaxis are expected to be below 30,000 pounds per QALY gained in healthy children, at-risk children, healthy elderly and at-risk elderly individuals. Despite favourable clinical efficacy estimates, the incorporation of recent evidence of viral resistance to amantadine led to it being dominated in every economic comparison.

CONCLUSIONS

All three interventions showed some efficacy for seasonal and post-exposure prophylaxis. However, weaknesses and gaps in the clinical evidence base are directly relevant to the interpretation of the health economic model and rendered the use of advanced statistical analyses inappropriate. These data limitations should be borne in mind in interpreting the findings of the review.

Restriction enzyme analysis of the apolipoprotein A-I gene in fish eye disease and Tangier disease

Restriction enzyme analysis of the apolipoprotein A-I (apo A-I) gene was performed in two patients with fish eye disease and one with Tangier disease. Despite the marked deficiency of high density lipoprotein and concomitantly of apo A-I in these two conditions, no evidence was found for major deletions or insertions in the apo A-I gene.

Use of classical and novel biomarkers as prognostic risk factors for localised prostate cancer: a systematic review

OBJECTIVES

To provide an evidence-based perspective on the prognostic value of novel markers in localised prostate cancer and to identify the best prognostic model including the three classical markers and investigate whether models incorporating novel markers are better.

DATA SOURCES

Eight electronic bibliographic databases were searched during March-April 2007. The reference lists of relevant articles were checked and various health services research-related resources consulted via the internet. The search was restricted to publications from 1970 onwards in the English language.

METHODS

Selected studies were assessed, data extracted using a standard template, and quality assessed using an adaptation of published criteria. Because of the heterogeneity regarding populations, outcomes and study type, meta-analyses were not undertaken and the results are presented in tabulated format with a narrative synthesis of the results.

RESULTS

In total 30 papers met the inclusion criteria, of which 28 reported on prognostic novel markers and five on prognostic models. A total of 21 novel markers were identified from the 28 novel marker studies. There was considerable variability in the results reported, the quality of the studies was generally poor and there was a shortage of studies in some categories. The marker with the strongest evidence for its prognostic significance was prostate-specific antigen (PSA) velocity (or doubling time). There was a particularly strong association between PSA velocity and prostate cancer death in both clinical and pathological models. In the clinical model the hazard ratio for death from prostate cancer was 9.8 (95% CI 2.8-34.3, p < 0.001) in men with an annual PSA velocity of more than 2 ng/ml versus an annual PSA velocity of 2 ng/ml or less; similarly, the hazard ratio was 12.8 (95% CI 3.7-43.7, p < 0.001) in the pathological model. The quality of the prognostic model studies was adequate and overall better than the quality of the prognostic marker studies. Two issues were poorly dealt with in most or all of the prognostic model studies: inclusion of established markers and consideration of the possible biases from study attrition. Given the heterogeneity of the models, they cannot be considered comparable. Only two models did not include a novel marker, and one of these included several demographic and co-morbidity variables to predict all-cause mortality. Only two models reported a measure of model performance, the C-statistic, and for neither was it calculated in an external data set. It was not possible to assess whether the models that included novel markers performed better than those without.

CONCLUSIONS

This review highlighted the poor quality and heterogeneity of studies, which render much of the results inconclusive. It also pinpointed the small proportion of models reported in the literature that are based on patient cohorts with a mean or median follow-up of at least 5 years, thus making long-term predictions unreliable. PSA velocity, however, stood out in terms of the strength of the evidence supporting its prognostic value and the relatively high hazard ratios. There is great interest in PSA velocity as a monitoring tool for active surveillance but there is as yet no consensus on how it should be used and, in particular, what threshold should indicate the need for radical treatment.

The acceptability to patients of computerized cognitive behaviour therapy for depression: a systematic review

BACKGROUND

Cognitive behaviour therapy (CBT) is widely used to treat depression. However, CBT is not always available to patients because of a shortage of therapists and long waiting times. Computerized CBT (CCBT) is one of several alternatives currently available to treat patients with depression. Evidence of its clinical effectiveness has led to programs being used increasingly within the UK and elsewhere. However, little information is available regarding the acceptability of CCBT to patients.

METHOD

A systematic review of sources of information on acceptability to patients of CCBT for depression.

RESULTS

Sources of information on acceptability included: recruitment rates, patient drop-outs and patient-completed questionnaires. We identified 16 studies of CCBT for the treatment of depression that provided at least some information on these sources. Limited information was provided on patient take-up rates and recruitment methods. Drop-out rates were comparable to other forms of treatment. Take-up rates, when reported, were much lower. Six of the 16 studies included specific questions on patient acceptability or satisfaction although information was only provided for those who had completed treatment. Several studies have reported positive expectancies and high satisfaction in routine care CCBT services for those completing treatment.

CONCLUSIONS

Trials of CCBT should include more detailed information on patient recruitment methods, drop-out rates and reasons for dropping out. It is important that well-designed surveys and qualitative studies are included alongside trials to determine levels and determinants of patient acceptability.

Taxanes for the adjuvant treatment of early breast cancer: systematic review and economic evaluation

OBJECTIVES

To estimate the clinical effectiveness and cost-effectiveness of docetaxel and paclitaxel compared with non-taxane, anthracycline-containing chemotherapy regimens, for the adjuvant treatment of women with early-stage breast cancer.

DATA SOURCES

Major electronic databases were searched between October 2005 and February 2006.

REVIEW METHODS

A systematic review of the literature on adjuvant taxane versus anthracycline non-taxane chemotherapy for women with early breast cancer was undertaken. A mathematical model was developed to synthesise the available data on costs, disease-free survival and health-related quality of life (HRQoL) of patients receiving taxane-containing chemotherapy versus non-taxane-containing chemotherapy.

RESULTS

Eight of the 11 selected trials (six docetaxel and five paclitaxel) reported a significant improvement in disease-free survival (DFS) or time to recurrence (TTR) for taxanes over comparator regimens. Docetaxel was associated with more adverse events than paclitaxel, most notably febrile neutropenia. Taxanes produced cardiotoxicity, although this was not reported to be greater than for anthracycline comparator arms in all trials. Treatment-related deaths were uncommon. Where reported, all chemotherapy regimens caused HRQoL to deteriorate during treatment. Following treatment, there were no clinically significant differences between taxane and comparator treatment groups. There were few data available comparing licensed regimens of taxanes with chemotherapy regimens commonly used in the UK. The three trials selected as the basis for the economic analysis were those that used the taxanes in accordance with current UK marketing authorisation and had also reported in full. The estimated incremental cost-effectiveness ratio for docetaxel compared to FAC6, based on the BCIRG 001 study, is 12,000 pounds (7000-39,000 pounds) and for paclitaxel compared with Adriamycin/cyclophosphamide, based on the NSABP B28 and CALGB 9344 studies, is 43,000 pounds (16,000 pounds-dominated) and 39,000 pounds (12,000 pounds-dominated), respectively. However, the comparators used in these trials restrict the generalisability of the results, as they do not conform to current standard care in the UK, typically FEC6 and E4-CMF4. An exploratory indirect comparison shows that the benefits of taxane containing regimens compared to regimens in current use in the UK is subject to large uncertainty due to the lack of direct trial comparisons between these interventions. Assumptions regarding the benefits in the taxane arm after the trial follow-up period and the annual rate of recurrence in this period have the most significant influence on the ICER.

CONCLUSIONS

There is a large degree of heterogeneity in the evidence base for the effectiveness of taxane- compared with non-taxane-containing regimens in terms of the interventions, comparators and populations. Eight of the 11 trials providing effectiveness data reported a significant improvement in DFS or TTR for taxanes over comparator regimens. The remaining three trials found no significant differences between the groups in DFS/TTR. The cost-effectiveness results suggest that the cost per quality-adjusted life-year for taxane- compared with non-taxane-containing chemotherapy varies between 12,000 pounds and 43,000 pounds, depending on the taxane under consideration and the specific trial used as the basis of the analysis. However, the comparators used in these trials do not conform to current standard care in the UK. More research is needed, comparing taxanes used in line with their current UK marketing authorisation and with anthracycline-containing regimens commonly used in the UK. The on-going TACT trial is expected to provide useful data. There are currently few data on the effectiveness of taxanes for the over-70s. Further research is required into the long-term outcomes of taxane therapy, such as whether there are any long-term adverse events that significantly impact on overall survival or quality of life and whether the increases in DFS will translate into increases in overall survival.

The distribution of nitric oxide synthase in the inferior colliculus of guinea pig

The modulation of neuronal activity by the gas nitric oxide is one of the most novel discoveries in neuroscience. In the auditory pathway, the highest expression of nitric oxide synthase is found in the inferior colliculus (IC), an important center for the convergence of parallel ascending pathways traveling in the brainstem, and descending projections from the auditory cortex. Here we use immunocytochemistry with an antibody for neuronal nitric oxide synthase (nNOS), or NOS Type 1, to map the distribution of nNOS expression in the IC of the guinea pig. The results show that nNOS is differentially expressed by both cell bodies and neuropil across its different subdivisions. The highest levels of neuronal staining are seen in the dorsal and lateral cortices, and the commissural nucleus, making them readily distinguishable from the ventro-lateral part of the central nucleus where nNOS expression in neuropil and somata is minimal. Dorso-medially, and caudally, however, the region of nNOS expression extends from the dorsal cortex into the area normally designated as the central nucleus, and nNOS is expressed by neurons characteristic of this subdivision. Our findings support the idea of a gradual transition in cell properties rather than a distinct boundary between the central nucleus and the dorsal cortex. This transition zone may provide a cytoarchitectonic substrate for functional interaction between these two subdivisions.