Predictive Factors for Magnetic Resonance Imaging Changes Suggestive of Demyelination in Adult Patients with Uveitis Scanned Prior to Commencing Adalimumab Therapy

PURPOSE

To report the predictive clinical factors for abnormal magnetic resonance imaging (MRI) scans suggestive of demyelination by analysis of MRI's performed for adult non-infectious uveitic patients prior to commencing adalimumab therapy.

METHODS

Retrospective case review of 240 patients was conducted in a single tertiary institution between November 2017 and March 2020. Aetiology of underlying disease, clinical characteristics, and MRI outcomes were analysed.

RESULTS

The presence of bilateral idiopathic intermediate uveitis (IIU) (p = .0048) and neurological symptoms (p = .028) were highly predictive of an abnormal MRI strongly suggestive of demyelination (MRSSD); 5 out of 64 scans (7.8%) with these clinical characteristics had MRSSD.

CONCLUSIONS

Tumor necrosis factor antagonist-induced demyelination is a concern in adalimumab use. We propose an MRI screening protocol to identify those at high risk of demyelination; positive results can be maximised by screening all patients with IIU and those with neurological symptoms.

The incidence, presenting clinical findings and treatment patterns of Birdshot Retinochoroiditis in a high-prevalence region: findings from Northern Ireland, England and Wales

BACKGROUND

Birdshot Retinochoroiditis (BSRC) is a rare, chronic posterior uveitis that is strongly associated with HLA-A*29.2 positivity. To date, no robust incidence studies of BSRC have been undertaken. We present the first epidemiological study of BSRC in a high-prevalence region.

METHODS

In collaboration with the British Ophthalmological Surveillance Unit, all new cases of BSRC between May 2017 and June 2019 were prospectively collected. Presenting demographics, symptoms, signs and treatment modalities were collected. A follow-up questionnaire twelve months later was also sent.

RESULTS

Thirty-seven confirmed cases meeting the reporting criteria were identified. Twenty-three cases had both baseline and follow-up data. The total population incidence of BSRC was 0.035 cases per 100,000 person-years [95% CI 0.025-0.048 cases per 100 000 people]. 97.3% were HLA-A*29 positive. The median age was 46 years, with females making up 78% of patients. There were no significant differences in the latitudinal incidence of BSRC. At presentation, floaters were the most common symptom. Optic disc swelling was the most common sign. Mean presenting visual acuity was independent of symptom duration. Combined systemic corticosteroids and immunomodulatory therapy were the most common treatments at baseline and follow-up. Intravitreal steroids were equally popular at follow-up.

CONCLUSIONS

This study provides the first nationwide estimate of the incidence of BSRC in a high-prevalence region. Cases were more common in females, with a broad range of presentation ages. No significant latitudinal effect of incidence was identified. Systemic therapy with steroids and IMT remain the most common treatments.

Immunosuppressive therapy for Vogt-Koyanagi-Harada disease: a retrospective study and review of literature

BACKGROUND

Vogt-Koyanagi-Harada (VKH) disease is an idiopathic autoimmune disease which targets melanin-containing tissues such as the uvea, meninges, ear and skin. This typically presents in the eye with acute findings of granulomatous anterior uveitis, diffuse choroidal thickening, multiple focal areas of sub-retinal fluid and, in severe cases, optic nerve involvement with bullous serous retinal detachment can occur. Early initiation of treatment has been advocated to prevent progression to the chronic stage of the disease, which can result to a sunset glow fundus with devastatingly poor visual outcome. Treatment is usually initiated with corticosteroids followed by an early introduction of immunosuppressive treatment (IMT) to achieve immediate response after disease presentation, although the choice of IMT for VKH can vary.

MAIN FINDINGS

We conducted a retrospective case-series to investigate the management trend of treating VKH over a 20-year period. Twenty-six patients were included and we found a shift from steroid monotherapy to combined IMT/low-dose steroid for the management of acute initial-onset of VKH in the last 10 years. Our average time from diagnosis to initiation of IMT was 2.1 months. 81% (21 of 26 patients) of our patients treated with combined IMT/steroid were able to achieve disease stability with significant good visual outcome at 24 months (Median VA_pre-IMT = 0.3 Logmar vs VA_post-IMT = 0.0 Logmar, p = 0.0001). MMF monotherapy was the most common IMT used and it was well-tolerated by our patients. Even so, 50% of our patients who were treated with MMF did not achieve disease control. We then performed a literature review to identify any IMT which could be superior in the treatment of VKH. We also share our experience (where applicable) on the various treatment options found from the literature review.

SHORT CONCLUSION

Our study found that patients with VKH who were treated with combined IMT/low-dose steroids achieved significantly better visual improvement at 24 months compared to steroid monotherapy. We frequently chose MMF and this appears to be well tolerated by our patients. Since its introduction, anti-TNF agents are increasingly becoming a popular choice of treatment for VKH as these have been shown to be safe and effective. However, more data is required to provide evidence that anti-TNF agents can be used as first-line treatment and as monotherapy.

Ischaemic stroke with multi-focal venous and arterial thrombosis due to hyperhomocysteinemia: anabolic androgenic steroid use and MTHFR c.667 C > T variant - a case report

BACKGROUND

Severely elevated serum homocysteine is a rare cause of ischaemic stroke and extra-cranial arterial and venous thrombosis. Several factors can lead to mild elevation of homocysteine including dietary folate and B12 deficiency, and genetic variants of the methylenetetrahydrofolate reductase (MTHFR) enzyme. The use of Anabolic androgenic steroid (AAS) is under-reported, but increasingly linked to ischaemic stroke and can raise homocysteine levels.

CASE REPORT

We present a case of a man in his 40s with a large left middle cerebral artery (MCA) territory ischaemic stroke and combined multifocal, extracranial venous, and arterial thrombosis. His past medical history was significant for Crohn's disease and covert use of AAS. A young stroke screen was negative except for a severely elevated total homocysteine concentration, folate and B12 deficiencies. Further tests revealed he was homozygous for the methylenetetrahydrofolate reductase enzyme thermolabile variant (MTHFR c.667 C > T). The etiology of this stroke was a hypercoagulable state induced by raised plasma homocysteine. Raised homocysteine in this case was likely multifactorial and related to chronic AAS use in combination with the homozygous MTHFR c.677 C > T thermolabile variant, folate deficiency and, vitamin B12 deficiency.

CONCLUSION

In summary, hyperhomocysteinemia is an important potential cause of ischaemic stroke and may result from genetic, dietary, and social factors. Anabolic androgenic steroid use is an important risk factor for clinicians to consider, particularly in cases of young stroke with elevated serum homocysteine. Testing for MFTHR variants in stroke patients with raised homocysteine may be useful to guide secondary stroke prevention through adequate vitamin supplementation. Further studies looking into primary and secondary stroke prevention in the high-risk MTHFR variant cohort are necessary.

Efficacy of Tacrolimus in Uveitis, and the Usefulness of Serum Tacrolimus Levels in Predicting Disease Control. Results from a Single Large Center

AIMS

To evaluate the efficacy of tacrolimus in patients with noninfectious uveitis, as well as the usefulness of serum tacrolimus concentration measurements in predicting disease control.

METHODS

A retrospective review was carried out on 71 eligible patients from a single specialist uveitis center for minimum 1-year follow-up. Analysis was carried out on disease activity, visual acuity, and trough serum tacrolimus concentrations (STC).

RESULTS

At 1-year follow-up, disease control was achieved in 49 patients (69.0%), this was significantly more likely in patients with trough STC levels above 5 ng/mL (88% vs 53%, p = .002). There was a significant reduction in oral prednisolone (dose ≥7.5 mg, 86% vs 54%, p < .0001). Tacrolimus was discontinued in 12 patients (17%) due to side effects.

DISCUSSION

In this study cohort, oral tacrolimus was effective and well tolerated in the treatment of noninfectious uveitis. Trough STC between 5 ng/mL and 10 ng/ml was associated with better disease control at 1-year follow-up.

Disseminated tuberculosis presenting as bilateral neuro-retinitis

Disseminated tuberculosis (TB) presenting with intraocular involvement is a rare condition, which can lead to profound visual loss if misdiagnosed. We report a case of a 24-year-old Nepalese male with disseminated TB who presented primarily with bilateral vision loss.

P-698 Pituitary functioning gonadotroph adenomas (FGA)-induced ovarian hyperstimulation syndrome (OHSS): results from tertiary neuroendocrine centres in the UK

Study question

There are no published series of OHSS due to FGA. What FGA features should clinicians look for during OHSS, and what treatments are effective?

Summary answer

FGA tumour size is always &gt;10mm. Other pituitary hormones may be deficient. Surgical resection of FGA is an effective treatment for OHSS.

What is known already

Pituitary adenomas affect 1:1000 adults and are classified as functioning or non-functioning. Non-functioning pituitary adenomas do not secrete hormones, but most commonly stain histologically gonadotroph cells. Functional pituitary adenomas secrete hormones such as prolactin causing prolactinoma. However, it is rare for a pituitary tumour to cause clinical features of excessive gonadotrophins (functioning gonadotroph adenoma; FGA).

Single case reports, but no case series, have been published on the presentation of FGA-induced OHSS in women.

Surgical excision of adenomas has been reported to cause remission of symptoms, though systematic data are lacking owing to rarity of these tumours.

Study design, size, duration

National case series from tertiary neuroendocrine units in England, Wales and Scotland.

Participants/materials, setting, methods

Eight high-volume pituitary endocrine tertiary units within England, Wales and Scotland audited their records for any cases of FGA-induced OHSS; only seven patients have been identified to date. In all cases, there had been no recent exposure to assisted reproductive technologies (ART) or drugs known to induce OHSS including gonadotrophins or selective oestrogen receptor modulators (SERMS).

Main results and the role of chance

Seven cases of FGA were identified with mean age 31.6 years (range 16-48) at diagnosis. Two-of-seven women presented acutely unwell with abdominal pain, distention and palpable mass requiring oophorectomy for ovarian torsion/ruptured ovarian cyst. The remaining five women presented with abdominal pain (n = 2), thyrotoxicosis (n = 1), menstrual irregularities/galactorrhoea (n = 1) and visual disturbances (n = 1). All women experienced intermittent pelvic pain during medical attendance. Pelvic ultrasound demonstrated enlarged multiseptated ovaries (volume ranging 27-442cm3). Ascites was noted in one woman. Six women had visual field defects due to optic chiasm compression on formal assessment. Median FSH was 26.10 u/L (8.3-33), but LH was &lt;2.5 u/L in all cases. Estradiol (E2) far exceeded the reference range in 5/7 women (2990 to &gt; 18000pmol/L);E2 was at the upper limit of normal in the remaining 2/7 women (960-1450pmol/L). Hyperprolactinaemia, hyperthyroidism and other pituitary hormones deficiency were noted in 6/7, 1/7 and 4/7 women respectively. All FGAs were macroadenomas with diameters ranging 16-48mm. Two patients were administered a somatostatin analogue prior to surgery, but FSH, E2 and tumour size did not change. Transsphenoidal surgery was performed in 6/7 women, and always improved symptomatic and biochemical features of OHSS; however, residual FGA tumour was present post-operatively in all cases studied.

Limitations, reasons for caution

It is possible that some ‘non-functioning’ gonadotroph adenomas cause subclinical problems including menstrual irregularity and mild OHSS which were never diagnosed.

We have insufficient data to determine the prognosis for future pregnancy after FGA-induced OHSS.

This study utilised historical case-notes, so some data is missing.

Wider implications of the findings

The ‘spontaneous’ presentation of OHSS may be confusing for clinicians. We report that FGA is an important cause of spontaneous OHSS which has well-defined biochemical and radiological characteristics, which may be treated effectively in the short-to-medium with pituitary surgery. Results of this study may provide greater awareness of FGA-induced OHSS.

Trial registration number

N/A

Ocular toxoplasmosis: phenotype differences between toxoplasma IgM positive and IgM negative patients in a large cohort

PURPOSE

To investigate the differences in demographics and clinical characteristics of patients diagnosed with ocular toxoplasmosis according to their IgM status.

METHODS

Retrospective case note analysis was carried out on patients who tested positive for serum Toxoplasma gondii-specific IgM antibodies (IgM+) as well as a comparator group who tested negative for serum IgM (IgM-), but positive for serum IgG. Patient demographics and clinical features were compared between the two groups to evaluate for any significant differences.

RESULTS

One hundred and six patients were included in the study between March 2011 and June 2018, consisting of 37 in the IgM +group and 69 in the IgM- group. Patients in the IgM +group were significantly older (51.1 vs 34.1 years, p<0.0001), more likely to present with central macular lesions (32% vs 12%, p=0.012), and more likely to develop rhegmatogenous retinal detachment (11% vs 1%, p=0.049). In contrast, patients in the IgM- group were more likely present with pain (20% vs 3%, 0.017) and exhibit more severe inflammation of the anterior chamber and vitreous (p<0.05). Overall, retinal lesions were more likely to be superotemporal (55%) and superonasal (31%). Furthermore, age was associated with larger (p=0.003) and more peripheral lesions (p=0.007).

CONCLUSIONS

This study demonstrated significant differences in clinical characteristics of ocular toxoplasmosis according to serum IgM status. IgM+ patients were older, less likely to report pain, had lower levels of intraocular inflammation, but were more likely to have macular involvement. We also found age to be correlated with larger and more peripheral lesions.

Multiple evanescent white dot syndrome: clinical course and factors influencing visual acuity recovery

Objective

To report the demographics and the clinical course of patients with multiple evanescent white dot syndrome (MEWDS) and to investigate for those factors which influence visual acuity (VA) recovery.

Methods

This is a retrospective single-centre observational study. Electronic medical records and retinal imaging of patients with a diagnosis of MEWDS with a minimum follow-up of 3 months were reviewed. Patients were categorised into three groups according to the VA at presentation and at the last visit: group 1 >0.48 logarithm of the minimum angle of resolution (LogMAR), group 2 ≤0.48 and ≥0.18 LogMAR and group 3 <0.18 LogMAR. All patients had non-invasive multimodal imaging including optical coherence tomography, near-infrared reflectance imaging and blue fundus autofluorescence at presentation and during follow-up.

Results

A total of 51 eyes from 51 patients (41 women, mean age 29.8±7.8 years) were included. Significantly more patients presented in the autumn (X2=8.69, p=0.034). The percentage of eyes recovering vision to 0.0 LogMAR or better was 80.3% (41/51). Worse presenting vision and young age at presentation were independent significant predictive variables for poorer final VA (p=0.002 and p=0.02, respectively). No imaging features were significantly predictive of complete versus incomplete recovery, but disc hyperfluorescence on fluorescein angiography was more common in those with incomplete recovery.

Conclusions

Although the majority of cases have a benign prognosis, the clinical spectrum of MEWDS includes incomplete visual recovery. In our series, poor presenting VA and young age were associated with poor VA outcome. Further study is warranted to confirm these findings.

Exploring the impacts of mindfulness and yoga upon childbirth outcomes and maternal health: an integrative review

BACKGROUND

Foetal development and the long-term outcomes of the infant are influenced by the intrauterine environment. Strategies to enhance maternal health in pregnancy are needed to improve health outcomes for childbearing women and babies, advancing the well-being of our general population.

AIM

To synthesise the existing literature to determine the impacts of mindfulness and yoga practice upon birth outcomes and maternal health.

METHODS

An integrative literature review using Whittemore and Knafl's framework was undertaken in 2016-2017. Two search strategies included database peer-reviewed journal articles and ancestry searching, that is exploring the reference list of relevant research articles. After screening and checking the eligibility, a total of 12 articles were included in this review. Data analysis involved coding, visual displays, thematic analysis and comparison, and conclusion drawing.

RESULTS

The results of this review identified a broad theme that mindfulness and yoga practice is associated with improved maternal mental health antenatally and postnatally. Subthemes have been presented under the central theme including the following: increased mindfulness correlates with decreased fear of childbirth; reduced symptoms of anxiety and depression; and supportive group settings found to be beneficial by pregnant women.

CONCLUSION

The evidence presented in this review suggests that mindfulness and yoga practice are feasible and cost-effective interventions to enhance maternal mental health, particularly for women experiencing mental health challenges. Mindfulness and yoga practised regularly in the antenatal period can significantly promote the health of pregnant women and potentially their developing babies.

Safety profile and efficacy of tacrolimus in the treatment of birdshot retinochoroiditis: a retrospective case series review

AIM

Evaluation of the use of tacrolimus in the treatment of birdshot retinochoroiditis (BRC) at a tertiary referral centre with the aim to describe its safety and efficacy.

METHODS

The medical records of 25 patients diagnosed with BRC at uveitis service, Moorfields Eye Hospital, and who had received tacrolimus treatment were retrospectively reviewed. The main outcome measures of the study were (1) safety of tacrolimus in terms of side effects and (2) efficacy, as measured both by control of inflammation and visual function assessed by Humphrey visual fields and electrophysiological testing over at least 6 months and then 1 year.

RESULTS

Tacrolimus was commenced in 25 patients (mean age 50.4±10.8 years) and was well tolerated in 21 patients (84%). It was necessary to stop the tacrolimus in four patients. No patient showed major changes in renal function: 3/21 patients (14.28%) showed slightly abnormal (less than 30%) function at the end of the first month of treatment; 1/21 (4.76%) patients at 3 months, but at the end of a 6-month treatment period only 1/21 patients (4.76%) showed minor abnormality in renal function. The mean daily prednisolone dose was 19.7 mg at the beginning of the study, which had fallen to 6.9 mg at the end (t=5.071, p=0.001). Visual acuity mostly remained stable. Visual fields improved over time (mean improvement in Humphrey mean deviation, right eye=1.8±2.4 dB, t=3.821, p=0.004; left eye=1.9±2.7, dB, t=3.06, p=0.007). Electrophysiological function showed improvement in 10 patients, and in four patients an initial deterioration in function improved following tacrolimus dose adjustment.

CONCLUSION

Tacrolimus has a good safety profile for long-term use in patients with BRC as a second-line agent enabling steroid sparing and visual function stabilisation or improvement.

Certifications for sight impairment due to age related macular degeneration in England

OBJECTIVES

To examine variability across England in certification rates for age related macular degeneration (AMD) between 1st April 2011 and 31st March 2012.

STUDY DESIGN

Cross-sectional survey.

METHODS

An electronic version of the CVI, the ECVI, was used at the Certifications Office, London, to transfer information from paper based certificates into a database. The electronic certifications data set was queried for all certificates completed in England between April 1st 2011 and March 31st 2012 with the main cause of certifiable visual loss being AMD or with the main cause of certifiable visual loss being multiple pathology but a contributory cause being AMD. Data were explored by type of AMD, visual status, age and sex and then directly standardized rates were computed by English region.

RESULTS

The Certifications Office received 23,616 CVIs for England between April 2011 and March 2012, of which 10,481 (44%) were people certified severely sight-impaired (blind) (SSI) and 12,689 (54%) were certified as sight-impaired (partial sight) (SI). The remainder did not have visual status classified. AMD contributed to 11546 causes of certification on the CVI forms during this period, 53% of forms being for geographic atrophy (GA)/dry AMD which is currently mostly untreatable. The median (interquartile) age at certification for AMD was 86 (81, 90) years and women were more commonly certified than men (66%). Considerable variability was seen across English regions, although there was consistency in that GA was the more common form in all areas.

CONCLUSIONS

There is considerable regional variability in CVI rates in England, which are not attributable to differences in age or sex. Reasons for such variability need examination yet this should not undermine the value of these data in terms of describing those newly registered with sight impairment due to AMD who are predominantly female and over 85 years of age.

Differences between men and women in the regulation of adipose 11β-HSD1 and in its association with adiposity and insulin resistance

This study explored sex differences in 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activity and gene expression in isolated adipocytes and adipose tissue (AT), obtained via subcutaneous biopsies from non-diabetic subjects [58 M, 64 F; age 48.3 ± 15.3 years, body mass index (BMI) 27.2 ± 3.9 kg/m²]. Relationships with adiposity and insulin resistance (IR) were addressed. Males exhibited higher 11β-HSD1 activity in adipocytes than females, but there was no such difference for AT. In both men and women, adipocyte 11β-HSD1 activity correlated positively with BMI, waist circumference, % body fat, adipocyte size and with serum glucose, triglycerides and low-density lipoprotein:high-density lipoprotein (LDL:HDL) ratio. Positive correlations with insulin, HOMA-IR and haemoglobin A1c (HbA1c) and a negative correlation with HDL-cholesterol were significant only in males. Conversely, 11β-HSD1 activity in AT correlated with several markers of IR and adiposity in females but not in males, but the opposite pattern was found with respect to 11β-HSD1 mRNA expression. This study suggests that there are sex differences in 11β-HSD1 regulation and in its associations with markers of obesity and IR.

What is the value of routinely testing full blood count, electrolytes and urea, and pulmonary function tests before elective surgery in patients with no apparent clinical indication and in subgroups of patients with common comorbidities: a systematic review of the clinical and cost-effective literature

BACKGROUND

The evidence base which supported the National Institute for Health and Clinical Excellence (NICE) published Clinical Guideline 3 was limited and 50% was graded as amber. However, the use of tests as part of pre-operative work-up remains a low-cost but high-volume activity within the NHS, with substantial resource implications. The objective of this study was to identify, evaluate and synthesise the published evidence on the clinical effectiveness and cost-effectiveness of the routine use of three tests, full blood counts (FBCs), urea and electrolytes tests (U&Es) and pulmonary function tests, in the pre-operative work-up of otherwise healthy patients undergoing minor or intermediate surgery in the NHS.

OBJECTIVE

The aims of this study were to estimate the clinical effectiveness and cost-effectiveness of routine pre-operative testing of FBC, electrolytes and renal function and pulmonary function in adult patients classified as American Society of Anaesthesiologists (ASA) grades 1 and 2 undergoing elective minor (grade 1) or intermediate (grade 2) surgical procedures; to compare NICE recommendations with current practice; to evaluate the cost-effectiveness of mandating or withdrawing each of these tests in this patient group; and to identify the expected value of information and whether or not it has value to the NHS in commissioning further primary research into the use of these tests in this group of patients.

DATA SOURCES

The following electronic bibliographic databases were searched: (1) BIOSIS; (2) Cumulative Index to Nursing and Allied Health Literature; (3) Cochrane Database of Systematic Reviews; (4) Cochrane Central Register of Controlled Trials; (5) EMBASE; (6) MEDLINE; (7) MEDLINE In-Process & Other Non-Indexed Citations; (8) NHS Database of Abstracts of Reviews of Effects; (9) NBS Health Technology Assessment Database; and (10) Science Citation Index. To identify grey and unpublished literature, the Cochrane Register of Controlled Trials, National Research Register Archive, National Institute for Health Research Clinical Research Network Portfolio database and the Copernic Meta-search Engine were searched. A large routine data set which recorded the results of tests was obtained from Leeds Teaching Hospitals Trust.

REVIEW METHODS

A systematic review of the literature was carried out. The searches were undertaken in March to April 2008 and June 2009. Searches were designed to retrieve studies that evaluated the clinical effectiveness and cost-effectiveness of routine pre-operative testing of FBC, electrolytes and renal function and pulmonary function in the above group of patients. A postal survey of current practice in testing patients in this group pre-operatively was undertaken in 2008. An exemplar cost-effectiveness model was constructed to demonstrate what form this would have taken had there been sufficient data. A large routine data set that recorded the results of tests was obtained from Leeds Teaching Hospitals Trust. This was linked to individual patient data with surgical outcomes, and regression models were estimated.

RESULTS

A comprehensive and systematic search of both the clinical effectiveness and cost-effectiveness literature identified a large number of potentially relevant studies. However, when these studies were subjected to detailed review and quality assessment, it became clear that the literature provides no evidence on the clinical effectiveness and cost-effectiveness of these specific tests in the specific patient groups. The postal survey had a 17% response rate. Results reported that in ASA grade 1, patients aged < 40 years with no comorbidities undergoing minor surgery did not have routine tests for FBC, electrolytes and renal function and pulmonary function. The results from the regression model showed that the frequency of test use was not consistent with the hypothesis of their routine use. FBC tests were performed in only 58% of patients in the data set and U&E testing was carried out in only 57%.

LIMITATIONS

Systematic searches of the clinical effectiveness and cost-effectiveness literature found that there is no evidence on the clinical effectiveness or cost-effectiveness of these tests in this specific clinical context for the NHS. A survey of NHS hospitals found that respondent trusts were implementing current NICE guidance in relation to pre-operative testing generally, and a de novo analysis of routine data on test utilisation and post-operative outcome found that the tests were not be used in routine practice; rather, use was related to an expectation of a more complex clinical case. The paucity of published evidence is a limitation of this study. The studies included relied on non-UK health-care systems data, which may not be transferable. The inclusion of non-randomised studies is associated with an increased risk of bias and confounding. Scoping work to establish the likely mechanism of action by which tests would impact upon outcomes and resource utilisation established that the cause of an abnormal test result is likely to be a pivotal determinant of the cost-effectiveness of a pre-operative test and therefore evaluations would need to consider tests in the context of the underlying risk of specific clinical problems (i.e. risk guided rather than routine use).

CONCLUSIONS

The time of universal utilisation of pre-operative tests for all surgical patients is likely to have passed. The evidence we have identified, though weak, indicates that tests are increasingly utilised in patients in whom there is a reason to consider an underlying raised risk of a clinical abnormality that should be taken into account in their clinical management. It is likely that this strategy has led to substantial resource savings for the NHS, although there is not a published evidence base to establish that this is the case. The total expenditure on pre-operative tests across the NHS remains significant. Evidence on current practice indicates that clinical practice has changed to such a degree that the original research question is no longer relevant to UK practice. Future research on the value of these tests in pre-operative work-up should be couched in terms of the clinical effectiveness and cost-effectiveness in the identification of specific clinical abnormalities in patients with a known underlying risk. We suggest that undertaking a multicentre study making use of linked, routinely collected data sets would identify the extent and nature of pre-operative testing in this group of patients.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

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.