Giant Carotid Artery Aneurysm

Carotid artery aneurysms account for 4% of peripheral aneurysms and may present as a neck mass, with hemispheric ischaemic symptoms, or with symptoms secondary to local compression. This case explores the presentation, investigations and management of a presumed mycotic common carotid artery aneurysm in a 77-year-old male, which was repaired using end-to-end interposition vein graft using long saphenous vein. This report discusses the aetiology, presentation and surgical management for carotid artery aneurysms, as well as focusing on that of the rare mycotic carotid artery aneurysm.

Hospital pharmacists' experiences of participating in a partnered pharmacist medication charting credentialing program: a qualitative study

BACKGROUND

Medication-related errors are one of the most frequently reported incidents in hospitals. With the aim of reducing the medication error rate, a Partnered Pharmacist Medication Charting (PPMC) model was trialled in seven Australian hospitals from 2016 to 2017. Participating pharmacists completed a credentialing program to equip them with skills to participate in the trial as a medication-charting pharmacist. Skills included obtaining a comprehensive medication history to chart pre-admission medications in collaboration with an admitting medical officer. The program involved both theoretical and practical components to assess the competency of pharmacists.

METHODS

A qualitative evaluation of the multi-site PPMC implementation trial was undertaken. Pharmacists and key informants involved in the trial participated in an interview or focus group session to share their experiences and attitudes regarding the PPMC credentialing program. An interview schedule was used to guide sessions. Transcripts were analysed using a pragmatic inductive-deductive thematic approach.

RESULTS

A total of 125 participants were involved in interviews or focus groups during early and late implementation data collection periods. Three themes pertaining to the PPMC credentialing program were identified: (1) credentialing as an upskilling opportunity, (2) identifying the essential components of credentialing, and (3) implementing and sustaining the PPMC credentialing program.

CONCLUSIONS

The PPMC credentialing program provided pharmacists with an opportunity to expand their scope of practice and consolidate clinical knowledge. Local adaptations to the PPMC credentialing program enabled pharmacists to meet the varying needs and capacities of hospitals, including the policies and procedures of different clinical settings. These findings highlight key issues to consider when implementation a credentialing program for pharmacists in the hospital setting.

A marking of the cricothyroid membrane with extended neck returns to correct position after neck manipulation and repositioning

BACKGROUND

Emergency front of neck airway access by anaesthetists carries a high failure rate and it is recommended to identify the cricothyroid membrane before induction of anaesthesia in patients with a predicted difficult airway. We have investigated whether a marking of the cricothyroid membrane done in the extended neck position remains correct after the patient's neck has been manipulated and subsequently repositioned.

METHODS

The subject was first placed in the extended head and neck position and had the cricothyroid membrane identified and marked with 3 methods, palpation, 'laryngeal handshake' and ultrasonography and the distance from the suprasternal notch to the cricothyroid membrane was measured. The subject then moved off the table and sat on a chair and subsequently returned to the extended neck position and examinations were repeated.

RESULTS

Skin markings of all 11 subjects lay within the boundaries of the cricothyroid membrane when the subject was repositioned back to the extended neck position and the median difference between the two measurements of the distance from the suprasternal notch was 0 mm (range 0-2 mm).

CONCLUSION

The cricothyroid membrane can be identified and marked with the subject in the extended neck position. Then the patient's position can be changed as needed, for example to the 'sniffing' neck position for conventional intubation. If a front of neck airway access is required during subsequent airway management, the patient can be returned expediently to the extended-neck position, and the marking of the centre of the membrane will still be in the correct place.

Automated Software System to Promote Anticoagulation and Reduce Stroke Risk: Cluster-Randomized Controlled Trial

BACKGROUND AND PURPOSE

Oral anticoagulants (OAC) substantially reduce risk of stroke in atrial fibrillation, but uptake is suboptimal. Electronic health records enable automated identification of people at risk but not receiving treatment. We investigated the effectiveness of a software tool (AURAS-AF [Automated Risk Assessment for Stroke in Atrial Fibrillation]) designed to identify such individuals during routine care through a cluster-randomized trial.

METHODS

Screen reminders appeared each time the electronic health records of an eligible patient was accessed until a decision had been taken over OAC treatment. Where OAC was not started, clinicians were prompted to indicate a reason. Control practices continued usual care. The primary outcome was the proportion of eligible individuals receiving OAC at 6 months. Secondary outcomes included rates of cardiovascular events and reports of adverse effects of the software on clinical decision-making.

RESULTS

Forty-seven practices were randomized. The mean proportion-prescribed OAC at 6 months was 66.3% (SD=9.3) in the intervention arm and 63.9% (9.5) in the control arm (adjusted difference 1.21% [95% confidence interval -0.72 to 3.13]). Incidence of recorded transient ischemic attack was higher in the intervention practices (median 10.0 versus 2.3 per 1000 patients with atrial fibrillation; P=0.027), but at 12 months, we found a lower incidence of both all cause stroke (P=0.06) and hemorrhage (P=0.054). No adverse effects of the software were reported.

CONCLUSIONS

No significant change in OAC prescribing occurred. A greater rate of diagnosis of transient ischemic attack (possibly because of improved detection or overdiagnosis) was associated with a reduction (of borderline significance) in stroke and hemorrhage over 12 months.

CLINICAL TRIAL REGISTRATION

URL: http://www.isrctn.com. Unique Identifier: ISRCTN55722437.

Optimal strategies for monitoring lipid levels in patients at risk or with cardiovascular disease: a systematic review with statistical and cost-effectiveness modelling

BACKGROUND

Various lipid measurements in monitoring/screening programmes can be used, alone or in cardiovascular risk scores, to guide treatment for prevention of cardiovascular disease (CVD). Because some changes in lipids are due to variability rather than true change, the value of lipid-monitoring strategies needs evaluation.

OBJECTIVE

To determine clinical value and cost-effectiveness of different monitoring intervals and different lipid measures for primary and secondary prevention of CVD.

DATA SOURCES

We searched databases and clinical trials registers from 2007 (including the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, the Clinical Trials Register, the Current Controlled Trials register, and the Cumulative Index to Nursing and Allied Health Literature) to update and extend previous systematic reviews. Patient-level data from the Clinical Practice Research Datalink and St Luke's Hospital, Japan, were used in statistical modelling. Utilities and health-care costs were drawn from the literature.

METHODS

In two meta-analyses, we used prospective studies to examine associations of lipids with CVD and mortality, and randomised controlled trials to estimate lipid-lowering effects of atorvastatin doses. Patient-level data were used to estimate progression and variability of lipid measurements over time, and hence to model lipid-monitoring strategies. Results are expressed as rates of true-/false-positive and true-/false-negative tests for high lipid or high CVD risk. We estimated incremental costs per quality-adjusted life-year.

RESULTS

A total of 115 publications reported strength of association between different lipid measures and CVD events in 138 data sets. The summary adjusted hazard ratio per standard deviation of total cholesterol (TC) to high-density lipoprotein (HDL) cholesterol ratio was 1.25 (95% confidence interval 1.15 to 1.35) for CVD in a primary prevention population but heterogeneity was high (I(2) = 98%); similar results were observed for non-HDL cholesterol, apolipoprotein B and other ratio measures. Associations were smaller for other single lipid measures. Across 10 trials, low-dose atorvastatin (10 and 20 mg) effects ranged from a TC reduction of 0.92 mmol/l to 2.07 mmol/l, and low-density lipoprotein reduction of between 0.88 mmol/l and 1.86 mmol/l. Effects of 40 mg and 80 mg were reported by one trial each. For primary prevention, over a 3-year period, we estimate annual monitoring would unnecessarily treat 9 per 1000 more men (28 vs. 19 per 1000) and 5 per 1000 more women (17 vs. 12 per 1000) than monitoring every 3 years. However, annual monitoring would also undertreat 9 per 1000 fewer men (7 vs. 16 per 1000) and 4 per 1000 fewer women (7 vs. 11 per 1000) than monitoring at 3-year intervals. For secondary prevention, over a 3-year period, annual monitoring would increase unnecessary treatment changes by 66 per 1000 men and 31 per 1000 women, and decrease undertreatment by 29 per 1000 men and 28 per 1000 men, compared with monitoring every 3 years. In cost-effectiveness, strategies with increased screening/monitoring dominate. Exploratory analyses found that any unknown harms of statins would need utility decrements as large as 0.08 (men) to 0.11 (women) per statin user to reverse this finding in primary prevention.

LIMITATION

Heterogeneity in meta-analyses.

CONCLUSIONS

While acknowledging known and potential unknown harms of statins, we find that more frequent monitoring strategies are cost-effective compared with others. Regular lipid monitoring in those with and without CVD is likely to be beneficial to patients and to the health service. Future research should include trials of the benefits and harms of atorvastatin 40 and 80 mg, large-scale surveillance of statin safety, and investigation of the effect of monitoring on medication adherence.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013003727.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Economic evaluation of a group-based exercise program for falls prevention among the older community-dwelling population

Background

Falls among older people are of growing concern globally. Implementing cost-effective strategies for their prevention is of utmost importance given the ageing population and associated potential for increased costs of fall-related injury over the next decades. The purpose of this study was to undertake a cost-utility analysis and secondary cost-effectiveness analysis from a healthcare system perspective, of a group-based exercise program compared to routine care for falls prevention in an older community-dwelling population.

Methods

A decision analysis using a decision tree model was based on the results of a previously published randomised controlled trial with a community-dwelling population aged over 70. Measures of falls, fall-related injuries and resource use were directly obtained from trial data and supplemented by literature-based utility measures. A sub-group analysis was performed of women only. Cost estimates are reported in 2010 British Pound Sterling (GBP).

Results

The ICER of GBP£51,483 per QALY for the base case analysis was well above the accepted cost-effectiveness threshold of GBP£20,000 to £30,000 per QALY, but in a sensitivity analysis with minimised program implementation the incremental cost reached GBP£25,678 per QALY. The ICER value at 95% confidence in the base case analysis was GBP£99,664 per QALY and GBP£50,549 per QALY in the lower cost analysis. Males had a 44% lower injury rate if they fell, compared to females resulting in a more favourable ICER for the women only analysis. For women only the ICER was GBP£22,986 per QALY in the base case and was below the cost-effectiveness threshold for all other variations of program implementation. The ICER value at 95% confidence was GBP£48,212 in the women only base case analysis and GBP£23,645 in the lower cost analysis. The base case incremental cost per fall averted was GBP£652 (GBP£616 for women only). A threshold analysis indicates that this exercise program cannot realistically break even.

Conclusions

The results suggest that this exercise program is cost-effective for women only. There is no evidence to support its cost-effectiveness in a group of mixed gender unless the costs of program implementation are minimal. Conservative assumptions may have underestimated the true cost-effectiveness of the program.

Electronic supplementary material

The online version of this article (doi:10.1186/s12877-015-0028-x) contains supplementary material, which is available to authorized users.

Specialist integrated haematological malignancy diagnostic services: an Activity Based Cost (ABC) analysis of a networked laboratory service model

AIMS

Specialist Integrated Haematological Malignancy Diagnostic Services (SIHMDS) were introduced as a standard of care within the UK National Health Service to reduce diagnostic error and improve clinical outcomes. Two broad models of service delivery have become established: 'co-located' services operating from a single-site and 'networked' services, with geographically separated laboratories linked by common management and information systems. Detailed systematic cost analysis has never been published on any established SIHMDS model.

METHODS

We used Activity Based Costing (ABC) to construct a cost model for our regional 'networked' SIHMDS covering a two-million population based on activity in 2011.

RESULTS

Overall estimated annual running costs were £1 056 260 per annum (£733 400 excluding consultant costs), with individual running costs for diagnosis, staging, disease monitoring and end of treatment assessment components of £723 138, £55 302, £184 152 and £94 134 per annum, respectively. The cost distribution by department was 28.5% for haematology, 29.5% for histopathology and 42% for genetics laboratories. Costs of the diagnostic pathways varied considerably; pathways for myelodysplastic syndromes and lymphoma were the most expensive and the pathways for essential thrombocythaemia and polycythaemia vera being the least.

CONCLUSIONS

ABC analysis enables estimation of running costs of a SIHMDS model comprised of 'networked' laboratories. Similar cost analyses for other SIHMDS models covering varying populations are warranted to optimise quality and cost-effectiveness in delivery of modern haemato-oncology diagnostic services in the UK as well as internationally.

Comparing supervised learning techniques on the task of physical activity recognition

The objective of this study was to compare the performance of base-level and meta-level classifiers on the task of physical activity recognition. Five wireless kinematic sensors were attached to each subject (n = 25) while they completed a range of basic physical activities in a controlled laboratory setting. Subjects were then asked to carry out similar self-annotated physical activities in a random order and in an unsupervised environment. A combination of time-domain and frequency-domain features were extracted from the sensor data including the first four central moments, zero-crossing rate, average magnitude, sensor cross-correlation, sensor auto-correlation, spectral entropy and dominant frequency components. A reduced feature set was generated using a wrapper subset evaluation technique with a linear forward search and this feature set was employed for classifier comparison. The meta-level classifier AdaBoostM1 with C4.5 Graft as its base-level classifier achieved an overall accuracy of 95%. Equal sized datasets of subject independent data and subject dependent data were used to train this classifier and high recognition rates could be achieved without the need for user specific training. Furthermore, it was found that an accuracy of 88% could be achieved using data from the ankle and wrist sensors only.

Health-related quality of life advantage of long-acting injectable antipsychotic treatment for schizophrenia: a time trade-off study

BACKGROUND

This study was undertaken to estimate utility values for alternative treatment intervals for long acting antipsychotic intramuscular injections for the treatment of schizophrenia.

METHODS

Vignettes were developed using the published literature and an iterative consultation process with expert clinicians and patient representative groups. Four vignettes were developed. The first was a vignette of relapsed/untreated schizophrenia. The other three vignettes presented a standardised picture of well-managed schizophrenia with variations in the intervals between injections: once every 2-weeks, 4-weeks and 3-months. A standardised time trade off (TTO) approach was used to obtain utility values for the vignettes. As a societal perspective was sought, a representative sample of individuals from across the community (Sydney, Australia) was recruited. Ninety-eight people completed the TTO interview. The vignettes were presented in random order to prevent possible ordering effects.

RESULTS

A clear pattern of increasing utility was observed with increasing time between injections. Untreated schizophrenia was rated as very poor health-related quality of life with a mean (median) utility of 0.27 (0.20). The treated health states were rated at much higher utilities and were statistically significantly different (p < 0.001) from each other: (1) 2-weekly: mean (median) utility = 0.61 (0.65); (2) 4-weekly: mean (median) utility = 0.65 (0.70); (3) 3-monthly: mean (median) utility = 0.70 (0.75).

CONCLUSIONS

This study has provided robust data indicating that approximately a 0.05 utility difference exists between treatment options, with the highest utility assigned to 3-monthly injections.

A cost analysis of febrile neutropenia management in Australia: ambulatory v. in-hospital treatment

BACKGROUND

Adult febrile neutropenic oncology patients, at low risk of developing medical complications, may be effectively and safely managed in an ambulatory setting, provided they are appropriately selected and adequate supportive facilities and clinical services are available to monitor these patients and respond to any clinical deterioration.

METHODS

A cost analysis was modelled using decision tree analysis, published cost and effectiveness parameters for ambulatory care strategies and data from the State of Victoria's hospital morbidity dataset. Two-way sensitivity analyses and Monte Carlo simulation were performed to evaluate the uncertainty of costs and outcomes associated with ambulatory care.

RESULTS

The modelled cost analysis showed that cost savings for two ambulatory care strategies were ~30% compared to standard hospital care. The weighted average cost saving per episode of 'low-risk' febrile neutropenia using Strategy 1 (outpatient follow-up only) was 35% (range: 7-55%) and that for Strategy 2 (early discharge and outpatient follow-up) was 30% (range: 7-39%). Strategy 2 was more cost-effective than Strategy 1 and was deemed the more clinically favoured approach.

CONCLUSION

This study outlines a cost structure for a safe and comprehensive ambulatory care program comprised of an early discharge pathway with outpatient follow-up, and promotes this as a cost effective approach to managing 'low-risk' febrile neutropenic patients.

The cost associated with administering risperidone long-acting injections in the Australian community

Background

Risperidone long-acting injection (LAI) is mostly administered twice weekly to people with schizophrenia by nurses at community mental health centres (CMHC) or through mobile outreach visits. This study estimates the cost of resource utilisation associated with the administration of risperidone LAI and the potential savings from substituting two-weekly injections with a longer interval product of therapeutic equivalence.

Methods

A survey of mental health staff overseeing the administration of risperidone LAI at 253 distinct Australian CMHCs was undertaken in November 2009. For the two-week period prior to the survey, respondents were asked questions on injection time (and related tasks) and, for mobile outreach visits, distance and time travelled as well as reduction in visits. Results were stratified by Australian Standard Geographical Classification (ASGC) region. Resource use was quantified and valued in Australian dollars.

Results

Results are derived from 74 CMHCs, representing approximately 26% of the national average risperidone LAI unit two-week sales. Stratified average injection time (including related tasks) for risperidone LAI ranged from 18-29 minutes, with a national average of 20.12 minutes. For mobile outreach visits, average distance per patient ranged from 19.4 to 55.5 km for One Staff Visits and 15.2 to 218.1 km for More Than One Staff Visits, and average time travelled ranged from 34.1 to 54.5 minutes for One Staff Visits and 29.2 to 136.3 minutes for More Than One Staff visits. The upper range consistently reflected greater resource utilisation in rural areas compared to urban areas. If administration of risperidone LAI had not been required, 20% fewer mobile outreach visits would have occurred.

Conclusions

The national average saving per two-weekly risperidone long-acting injection avoided is $75.14. In 2009 in Australia, this would have saved ~$11 million for injection administration costs alone if all patients taking two-weekly risperidone LAI had instead been treated with a therapeutically equivalent long-acting injectable antipsychotic requiring one less injection per month.

Collagen gene polymorphisms influence fracture risk and bone mass acquisition during childhood and adolescent growth

Fractures are common in childhood with incidence maximal during puberty, around the time of peak height velocity. The relationships between single nucleotide polymorphisms (SNPs) in COL1A1 and COL1A2, bone mass acquisition, and childhood fractures are unclear. We recruited 394 children and adolescents aged 4 to 16 years into a noninterventional case control study. All had suffered an episode of trauma leading to hospital presentation; 205 had sustained a fracture. We determined the frequency of COL1A1 Sp1 and COL1A2 PvuII SNPs. Lumbar spine dual-energy X-ray absorptiometry (DXA) measurements were compared between fracture and control groups according to genotype. Subgroup analyses were performed according to sex, pubertal status, and site of injury. We found that the COL1A2 'PP' genotype approximately halved the odds of fracture in the study group as a whole (OR=0.45 [95% CI=0.24-0.82], p=0.01). In particular, possession of the same genotype by subjects who had not yet progressed beyond midpuberty was associated with reduced odds of fracture (OR=0.38 [95% CI=0.19-0.79], p=0.01) and significantly increased lumbar spine bone mineral content (p=0.03) and areal bone mineral density (p=0.007). The COL1A1 Sp1 binding site 's' allele was associated with a trebling of the odds of fracture in prepubertal children (OR=3.1 [95% CI=1.43-6.61], p=0.004), but there was no association with any DXA measures. This is the first paediatric study to our knowledge that shows an association of the COL1A2 PvuII restriction site 'PP' genotype with a reduced risk of fracture and of the COL1A1 Sp1 binding site 's' allele with an increased risk. The association of these variants with fracture risk is greatest during periods of predominantly appendicular bone growth.

Single-shot optical conductivity measurement of dense aluminum plasmas

The optical conductivity of a dense femtosecond laser-heated aluminum plasma heated to 0.1-1.5 eV was measured using frequency-domain interferometry with chirped pulses, permitting simultaneous observation of optical probe reflectivity and probe pulse phase shift. Coupled with published models of bound-electron contributions to the conductivity, these two independent experimental data yielded a direct measurement of both real and imaginary components of the plasma conductivity.

Equation-of-state measurement of dense plasmas heated with fast protons

Using an ultrafast pulse of mega-electron-volt energy protons accelerated from a laser-irradiated foil, we have heated solid density aluminum plasmas to temperatures in excess of 15 eV. By measuring the temperature and the expansion rate of the heated Al plasma simultaneously and with picosecond time resolution we have found the predictions of the SESAME Livermore equation-of-state (LEOS) tables to be accurate to within 18%, in this dense plasma regime, where there have been few previous experimental measurements.

Quality of life related to oral versus subcutaneous iron chelation: a time trade-off study

OBJECTIVE

To investigate the utility associated with subcutaneous infusion (deferoxamine) compared with once-daily oral administration (deferasirox) of iron chelation therapy.

METHODS

Interviews using the time trade-off technique were used to estimate preferences (utility) for health states by finding the point at which respondents were indifferent between a longer but lower quality of life (QoL) and a shorter time in full health. Participants (n = 110) were community-based, 51% women, median age 35 years, from four regions in Sydney, Australia. Respondents rated three health states involving equal outcomes for people with thalassemia but with different treatment modalities for iron chelation; an "anchor state" describing a patient receiving iron chelation without administration mode specified, anchor state plus iron chelation via subcutaneous infusion, and anchor state plus iron chelation through once-daily oral medication.

RESULTS

On an interval scale between 0 (death) and 1 (full health), median (interquartile range) utility of 0.80 (0.65-0.95) for the anchor state, 0.66 (0.45-0.87) for subcutaneous infusion, and 0.93 (0.80-0.97) for once-daily oral administration was obtained. The mean (median) difference of 0.23 (0.27) between the two treatments was statistically significant (Wilcoxon-signed rank test, P < 0.001). Subcutaneous infusion was associated with a mean (median) utility 0.13 (0.14) lower than the anchor state (P < 0.001), and once-daily oral treatment had a utility 0.10 (0.13) higher (P < 0.001).

CONCLUSION

Community respondents associate oral administration of an iron chelator such as deferasirox with enhanced QoL compared with subcutaneous treatment. Assuming equal safety and efficacy, QoL gains from once-daily oral treatment compared with subcutaneous infusion are significant.

High frequency of missense mutations in glycogen storage disease type VI

Deficiency of liver glycogen phosphorylase in glycogen storage disease (GSD) type VI results in a reduced ability to mobilize glucose from glycogen. Six mutations of the PYGL gene, which encodes the liver isoform of the enzyme, have been identified in the literature. We have characterized eight patients from seven families with GSD type VI and identified 11 novel PYGL gene defects. The majority of the mutations were missense, resulting in the substitution of highly conserved residues. These could be grouped into those that were predicted to affect substrate binding (p.V456M, p.E673K, p.S675L, p.S675T), pyridoxal phosphate binding (p.R491C, p.K681T), or activation of glycogen phosphorylase (p.Q13P) or that had an unknown effect (p.N632I and p.D634H). Two mutations were predicted to result in null alleles, p.R399X and [c.1964_1969inv6;c.1969+1_+4delGTAC]. Only 7 of the 23 (30%) reported PYGL alleles carry nonsense, splice site or frameshift mutations compared to 68-80% of affected alleles of the highly homologous muscle glycogen phosphorylase gene, PYGM, that underlie McArdle disease. There was heterogeneity in the clinical symptoms observed in affected individuals. These varied from hepatomegaly and subclinical hypoglycaemia, to severe hepatomegaly with recurrent severe hypoglycaemia and postprandial lactic acidosis. We conclude that deficiency of liver glycogen phosphorylase is predominantly the result of missense mutations affecting enzyme activity. There are no common mutations and the severity of clinical symptoms varies significantly.

Reduced penetrance alleles for Huntington's disease: a multi-centre direct observational study

OBJECTIVE

To obtain penetrance data for Huntington's disease when DNA results are in the range of 36-39 CAG repeats and assess the consistency of reporting the upper allele from two reference centres.

METHOD

Data were collected anonymously on age of onset or age last known to be unaffected from a cohort of individuals with results in this range. DNA samples were re-analysed in two reference centres. Kaplan-Meier analysis was used to construct an age of onset curve and penetrance figures.

RESULTS

Clinical data and concordant DNA results from both reference centres were available for 176 samples; penetrance figures (and 95% confidence intervals) for this cohort, at age 65 and 75 years, were 63.9% (55.5% to 73.2%) and 74.2% (64.2% to 84.2%), respectively. Inclusion of 28 additional subjects for whom repeat DNA results were unavailable, obtained from only one reference centre, or discrepant by one repeat within this range, gave penetrance data (including 95% confidence intervals) at ages 65 and 75 years of 62.4% (54.4% to 70.4%) and 72.7.% (63.3% to 82.1%), respectively. 238 duplicate results were available from the reference centres; 10 (4.2%) differed by one CAG repeat in the reporting of the upper allele and in two (0.84%) of these cases the discrepancy was between 39 and 40 repeats.

CONCLUSION

When DNA results are in this range, a conservative approach is to say that there is at least a 40% chance the person will be asymptomatic at age 65 years and at least a 30% chance the person will be asymptomatic at age 75 years.

Diagnostic assays and sampling protocols for the detection of Batrachochytrium dendrobatidis

Batrachochytrium dendrobatidis is a fungus belonging to the Phylum Chytridiomycota, Class Chytridiomycetes, Order Chytridiales, and is the highly infectious aetiological agent responsible for a potentially fatal disease, chytridiomycosis, which is currently decimating many of the world's amphibian populations. The fungus infects 2 amphibian orders (Anura and Caudata), 14 families and at least 200 species and is responsible for at least 1 species extinction. Whilst the origin of the agent and routes of transmission are being debated, it has been recognised that successful management of the disease will require effective sampling regimes and detection assays. We have developed a range of unique sampling protocols together with diagnostic assays for the detection of B. dendrobatidis in both living and deceased tadpoles and adults. Here, we formally present our data and discuss them in respect to assay sensitivity, specificity, repeatability and reproducibility. We suggest that compliance with the recommended protocols will avoid the generation of spurious results, thereby providing the international scientific and regulatory community with a set of validated procedures which will assist in the successful management of chytridiomycosis in the future.

Clinical features of hereditary spastic paraplegia due to spastin mutation

BACKGROUND

Mutations in the spastin gene are the commonest cause of hereditary spastic paraparesis (HSP), accounting for up to 40% of autosomal dominant cases. The phenotype associated with HSP due to mutation in the spastin gene (SPG4) tends to be pure HSP.

OBJECTIVE

To characterize in more detail the genetic and phenotypic characteristics of SPG4 by examining a large cohort of patients with HSP.

METHODS

The authors identified patients who tested positive for spastin mutation using a direct sequencing approach of all exons.

RESULTS

The authors identified spastin mutations in 53 patients. Twenty-seven of the mutations identified were novel. The phenotype in the majority of patients was of pure HSP. In one individual, a complicated phenotype with progressive bulbar dysfunction and respiratory insufficiency was observed. Evidence of lower motor neuron dysfunction in a subgroup of SPG4 patients was identified. The missense changes S44L and P45Q were identified in patients with other spastin mutations and seemed to be exerting a phenotype-modifying effect.

CONCLUSION

These findings add to the number of spastin mutations identified and demonstrate the importance of screening the whole gene, given the possibility of double mutations and intragenic modifiers. The identification of the complicated phenotypes has important implications for identifying the phenotype of patients in whom spastin screening should be considered. The presence of lower motor neuron dysfunction in a subgroup of SPG4 patients suggests that the cellular dysfunction in SPG4 extends beyond the axonal projections of upper motor neurons and ascending sensory pathways.

Pulmonary infection in mild variant cystic fibrosis: implications for care

BACKGROUND

Disease phenotype in cystic fibrosis (CF) shows considerable heterogeneity. Atypical or mild mutations in the CFTR gene have been linked to late-onset pulmonary disease; however, few reports document the condition of the airway in infants and young children with apparent "mild" disease. Prognosis is uncertain in this group of patients and this, in turn, has led to inconsistency in management. Our initial experience of pulmonary infection in children with mild variant CF prompted a more detailed review of clinical outcome.

METHODS

A retrospective cohort study was carried out comparing frequency of bacterial isolates and clinical outcomes in eleven compound heterozygotes for DeltaF508 and a second mild mutation, mainly R117H, with a matched group of DeltaF508 homozygotes.

RESULTS

Staphylococcus aureus was isolated in 8 of the 11 patients with mild variant disease and Pseudomonas aeruginosa found in 7 (64%), although the frequency of positive cultures was significantly less (2.8/year) than the DeltaF508 homozygotes (6.1/year, p<0.05). Shwachman scores (median+range) were significantly higher in patients with mild mutations - 94, 74-92 vs. 88, 77-91; p<0.005); there was also a small but significant difference in chest radiograph (Chrispin-Norman) scores (median+range) (mild 5.1, 4-9, vs. severe 5.8, 3-10; p 0.04). There was little difference in lung function in terms of FEV1 (median+range) between the two groups (% predicted, mild 86.5, 68-87 vs. severe 76.0, 65-88; p 0.5).

CONCLUSIONS

Most patients with mild variant CF will have bacterial isolates from airway cultures requiring antibiotic therapy three to four times a year. Infection with both S. aureus and P. aeruginosa is common. Anti-staphylococcal prophylaxis for the first two years should be considered.

Infantile hereditary spastic paraparesis due to codominant mutations in the spastin gene

The authors describe an infant with a severe spastic paraparesis caused by two codominant mutations of the spastin gene. This highlights the multiple molecular mechanisms that are likely to be involved in the molecular pathology of SPG4 and illustrates the importance of complete screening of the spastin gene in affected individuals, particularly if the index case has an unusual phenotype.

Cost-effectiveness analysis of screening for lung cancer with low dose spiral CT (computed tomography) in the Australian setting

INTRODUCTION

Low dose spiral computed tomography (CT) is a sensitive screening tool for lung cancer that is currently being evaluated in both non-randomised studies and randomised controlled trials.

METHODS

We conducted a quantitative decision analysis using a Markov model to determine whether, in the Australian setting, offering spiral CT screening for lung cancer to high risk individuals would be cost-effective compared with current practice. This exploratory analysis was undertaken predominantly from the perspective of the government as third-party funder. In the base-case analysis, the costs and health outcomes (life-years saved and quality-adjusted life years) were calculated in a hypothetical cohort of 10,000 male current smokers for two alternatives: (1) screen for lung cancer with annual CT for 5 years starting at age 60 year and treat those diagnosed with cancer or (2) no screening and treat only those who present with symptomatic cancer.

RESULTS

For male smokers aged 60-64 years, with an annual incidence of lung cancer of 552 per 100,000, the incremental cost-effectiveness ratio was 57,325 dollars per life-year saved and 105,090 dollars per QALY saved. For females aged 60-64 years with the same annual incidence of lung cancer, the cost-effectiveness ratio was 51,001 dollars per life-year saved and 88,583 dollars per QALY saved. The model was used to examine the relationship between efficacy in terms of the expected reduction in lung cancer mortality at 7 years and cost-effectiveness. In the base-case analysis lung cancer mortality was reduced by 27% and all cause mortality by 2.1%. Changes in the estimated proportion of stage I cancers detected by screening had the greatest impact on the efficacy of the intervention and the cost-effectiveness. The results were also sensitive to assumptions about the test performance characteristics of CT scanning, the proportion of lung cancer cases overdiagnosed by screening, intervention rates for benign disease, the discount rate, the cost of CT, the quality of life in individuals with early stage screen-detected cancer and disutility associated with false positive diagnoses. Given current knowledge and practice, even under favourable assumptions, reductions in lung cancer mortality of less than 20% are unlikely to be cost-effective, using a value of 50,000 dollars per life-year saved as the threshold to define a "cost-effective" intervention.

CONCLUSION

The most feasible scenario under which CT screening for lung cancer could be cost-effective would be if very high-risk individuals are targeted and screening is either highly effective or CT screening costs fall substantially.