Randomized trial of near-infrared spectroscopy for personalized optimization of cerebral tissue oxygenation during cardiac surgery.

BACKGROUND: We assessed whether a near-infrared spectroscopy (NIRS)-based algorithm for the personalized optimization of cerebral oxygenation during cardiopulmonary bypass combined with a restrictive red cell transfusion threshold would reduce perioperative injury to the brain, heart, and kidneys. METHODS: In a randomized controlled trial, participants in three UK centres were randomized with concealed allocation to a NIRS (INVOS 5100; Medtronic Inc., Minneapolis, MN, USA)-based 'patient-specific' algorithm that included a restrictive red cell transfusion threshold (haematocrit 18%) or to a 'generic' non-NIRS-based algorithm (standard care). The NIRS algorithm aimed to maintain cerebral oxygenation at an absolute value of > 50% or at > 70% of baseline values. The primary outcome for the trial was cognitive function measured up to 3 months postsurgery. RESULTS: The analysis population comprised eligible randomized patients who underwent valve or combined valve surgery and coronary artery bypass grafts using cardiopulmonary bypass between December 2009 and January 2014 ( n =98 patient-specific algorithm; n =106 generic algorithm). There was no difference between the groups for the three core cognitive domains (attention, verbal memory, and motor coordination) or for the non-core domains psychomotor speed and visuo-spatial skills. The NIRS group had higher scores for verbal fluency; mean difference 3.73 (95% confidence interval 1.50, 5.96). Red cell transfusions, biomarkers of brain, kidney, and myocardial injury, adverse events, and health-care costs were similar between the groups. CONCLUSIONS: These results do not support the use of NIRS-based algorithms for the personalized optimization of cerebral oxygenation in adult cardiac surgery. CLINICAL TRIAL REGISTRATION: http://www.controlled-trials.com , ISRCTN 23557269.

Adaptation of the By-Band randomized clinical trial to By-Band-Sleeve to include a new intervention and maintain relevance of the study to practice.

BACKGROUND: Recruitment into surgical RCTs can be threatened if new interventions available outside the trial compete with those being evaluated. Adapting the trial to include the new intervention may overcome this issue, yet this is not often done in surgery. This paper describes the challenges, rationale and methods for adapting an RCT to include a new intervention. METHODS: The By-Band study was designed in the UK in 2009-2010 to compare the effectiveness of laparoscopic adjustable gastric band and Roux-en-Y gastric bypass for severe obesity. It contained a pilot phase to establish whether recruitment was possible, and the grant proposal specified that an adaptation to include sleeve gastrectomy would be considered if practice changed and recruitment was successful. Information on changing obesity surgery practice, updated evidence and expert opinion about trial design were used to inform the adaptation. RESULTS: The pilot phase recruited over 13 months in 2013-2014 and randomized 80 patients (79 anticipated). During this time, major changes in obesity practice in the UK were observed, with gastric band reducing from 32·6 to 15·8 per cent and sleeve gastrectomy increasing from 9·0 to 28·1 per cent. The evidence base had not changed markedly. The British Obesity and Metabolic Surgery Society and study oversight committees supported an adaptation to include sleeve gastrectomy, and a proposal to do so was approved by the funder. CONCLUSION: Adaptation of a two-group surgical RCT can allow evaluation of a third procedure and maintain relevance of the RCT to practice. It also optimizes the use of existing trial infrastructure to answer an additional important research question. Registration number: ISRCTN00786323 (http://www.isrctn.com/).

Cost-effectiveness of community versus hospital eye service follow-up for patients with quiescent treated age-related macular degeneration alongside the ECHoES randomised trial.

OBJECTIVES: To assess the cost-effectiveness of optometrist-led follow-up monitoring reviews for patients with quiescent neovascular age-related macular degeneration (nAMD) in community settings (including high street opticians) compared with ophthalmologist-led reviews in hospitals. DESIGN: A model-based cost-effectiveness analysis with a 4-week time horizon, based on a 'virtual' non-inferiority randomised trial designed to emulate a parallel group design. SETTING: A virtual internet-based clinical assessment, conducted at community optometry practices, and hospital ophthalmology clinics. PARTICIPANTS: Ophthalmologists with experience in the age-related macular degeneration service; fully qualified optometrists not participating in nAMD shared care schemes. INTERVENTIONS: The participating optometrists and ophthalmologists classified lesions from vignettes and were asked to judge whether any retreatment was required. Vignettes comprised clinical information, colour fundus photographs and optical coherence tomography images. Participants' classifications were validated against experts' classifications (reference standard). Resource use and cost information were attributed to these retreatment decisions. MAIN OUTCOME MEASURES: Correct classification of whether further treatment is needed, compared with a reference standard. RESULTS: The mean cost per assessment, including the subsequent care pathway, was £411 for optometrists and £397 for ophthalmologists: a cost difference of £13 (95% CI -£18 to £45). Optometrists were non-inferior to ophthalmologists with respect to the overall percentage of lesions correctly assessed (difference -1.0%; 95% CI -4.5% to 2.5%). CONCLUSIONS: In the base case analysis, the slightly larger number of incorrect retreatment decisions by optometrists led to marginally and non-significantly higher costs. Sensitivity analyses that reflected different practices across eye hospitals indicate that shared care pathways between optometrists and ophthalmologists can be identified which may reduce demands on scant hospital resources, although in light of the uncertainty around differences in outcome and cost it remains unclear whether the differences between the 2 care pathways are significant in economic terms. TRIAL REGISTRATION NUMBER: ISRCTN07479761; Pre-results.

Are lower levels of red blood cell transfusion more cost-effective than liberal levels after cardiac surgery? Findings from the TITRe2 randomised controlled trial.

OBJECTIVE: To assess the incremental cost and cost-effectiveness of a restrictive versus a liberal red blood cell transfusion threshold after cardiac surgery. DESIGN: A within-trial cost-effectiveness analysis with a 3-month time horizon, based on a multicentre superiority randomised controlled trial from the perspective of the National Health Service (NHS) and personal social services in the UK. SETTING: 17 specialist cardiac surgery centres in UK NHS hospitals. PARTICIPANTS: 2003 patients aged >16 years undergoing non-emergency cardiac surgery with a postoperative haemoglobin of <9 g/dL. INTERVENTIONS: Restrictive (transfuse if haemoglobin <7.5 g/dL) or liberal (transfuse if haemoglobin <9 g/dL) threshold during hospitalisation after surgery. MAIN OUTCOME MEASURES: Health-related quality of life measured using the EQ-5D-3L to calculate quality-adjusted life years (QALYs). RESULTS: The total costs from surgery up to 3 months were £17 945 and £18 127 in the restrictive and liberal groups (mean difference is -£182, 95% CI -£1108 to £744). The cost difference was largely attributable to the difference in the cost of red blood cells. Mean QALYs to 3 months were 0.18 in both groups (restrictive minus liberal difference is 0.0004, 95% CI -0.0037 to 0.0045). The point estimate for the base-case cost-effectiveness analysis suggested that the restrictive group was slightly more effective and slightly less costly than the liberal group and, therefore, cost-effective. However, there is great uncertainty around these results partly due to the negligible differences in QALYs gained. CONCLUSIONS: We conclude that there is no clear difference in the cost-effectiveness of restrictive and liberal thresholds for red blood cell transfusion after cardiac surgery. TRIAL REGISTRATION NUMBER: ISRCTN70923932; Results.

The design and implementation of a study to investigate the effectiveness of community vs hospital eye service follow-up for patients with neovascular age-related macular degeneration with quiescent disease.

IntroductionStandard treatment for neovascular age-related macular degeneration (nAMD) is intravitreal injections of anti-VEGF drugs. Following multiple injections, nAMD lesions often become quiescent but there is a high risk of reactivation, and regular review by hospital ophthalmologists is the norm. The present trial examines the feasibility of community optometrists making lesion reactivation decisions.MethodsThe Effectiveness of Community vs Hospital Eye Service (ECHoES) trial is a virtual trial; lesion reactivation decisions were made about vignettes that comprised clinical data, colour fundus photographs, and optical coherence tomograms displayed on a web-based platform. Participants were either hospital ophthalmologists or community optometrists. All participants were provided with webinar training on the disease, its management, and assessment of the retinal imaging outputs. In a balanced design, 96 participants each assessed 42 vignettes; a total of 288 vignettes were assessed seven times by each professional group.The primary outcome is a participant's judgement of lesion reactivation compared with a reference standard. Secondary outcomes are the frequency of sight threatening errors; judgements about specific lesion components; participant-rated confidence in their decisions about the primary outcome; cost effectiveness of follow-up by optometrists rather than ophthalmologists.DiscussionThis trial addresses an important question for the NHS, namely whether, with appropriate training, community optometrists can make retreatment decisions for patients with nAMD to the same standard as hospital ophthalmologists. The trial employed a novel approach as participation was entirely through a web-based application; the trial required very few resources compared with those that would have been needed for a conventional randomised controlled clinical trial.

Management of patients with suspected infectious diarrhoea in hospitals in England.

BACKGROUND: Advances in molecular and genomic testing for patients with suspected infectious diarrhoea are on the horizon. It is important to understand how infection control and microbiology departments currently operate with respect to the management of these patients in order to assess the implications of more widespread diagnostic testing. However, there are few data available on current practice in this context. AIM: To describe current infection control and microbiologist practice across England with respect to the management of patients with suspected infectious diarrhoea. METHODS: Hospitals in England completed three questionnaires on current testing practice in this context. Questionnaire design was informed by current practice within the Oxford University Hospitals group. FINDINGS: Forty-one percent of hospitals completed at least one questionnaire. A notable proportion of staff time was devoted to the management of patients with suspected infectious diarrhoea. Staff training was generally good, but compliance with policy documents was only 80%. Cleaning and isolation policies varied across hospitals, suggesting that either these were not evidence-based, or that the evidence base is weak. There was more agreement on outbreak definitions, management, and cohorting policies. Stool-testing decisions were mainly driven by patient characteristics, whereas strain typing was infrequently used (except to investigate Clostridium difficile infections). Multiple practical difficulties associated with patient management were identified, along with a clear appetite for more widespread genomic diagnostic testing. CONCLUSION: Managing patients with suspected infectious diarrhoea is a major burden in England. Advances in testing practice in this context could have significant clinical and economic impacts.

Regional differences in the frequency of the c.985A>G ACADM mutation: findings from a meta-regression of genotyping and screening studies.

Several countries include medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, a rare autosomal recessive disease, in their newborn screening programmes despite prevalence uncertainty. We estimated the frequency of its most common mutation, c.985A>G, tested for regional differences and compared screening and genotype frequencies. We identified 43 studies reporting the frequency of c.985A>G over 10 million individuals, and pooled frequency data using a novel Bayesian approach. We found significant variation in the frequency of the mutation across regions supporting a reported founder effect. The proportion of c.985A>G homozygotes was highest in Western Europe with 4.1 (95%CI: 2.8-5.6) per 100,000 individuals, then the New World (3.2, 95%CI: 2.0-4.7), Southern (1.2, 95%CI: 0.6-2.0) and Eastern European regions (0.9, 95%CI: 0.5-1.7). No cases with the mutation were identified in Asian and Middle Eastern regions. Significant differences were found in some countries between the genotype and screening allele frequency of c.985A>G. Our predictions could inform the frequency of the mutation by region and our approach could apply to other genetic conditions.

Clomifene citrate and intrauterine insemination as first-line treatments for unexplained infertility: are they cost-effective?

BACKGROUND: First-line treatments for unexplained infertility traditionally include clomifene citrate (CC) or unstimulated intrauterine insemination (IUI). A recently published randomized controlled trial considered the effectiveness of CC and IUI in patients with unexplained infertility and found that neither treatment offered a superior live birth rate when compared with expectant management (EM). This paper reports the economic evaluation conducted alongside this trial in order to assess whether health care providers are gaining value for money in this clinical area. METHODS: Five hundred and eighty women across five Scottish hospitals were randomized to either EM, CC or IUI for 6 months. The primary outcome measure was live births. Resource-use data were collected during the trial and costs were calculated from a UK National Health Service (NHS) perspective. Incremental cost-effectiveness ratios were calculated, expressed as cost per live birth, in order to compare the cost-effectiveness of CC and IUI with that of EM to treat unexplained infertility. RESULTS: Live birth rates in the three randomized groups were: EM = 32/193 (17%), CC = 26/194 (13%) and IUI = 43/193 (22%). The mean (standard deviation) costs per treatment cycle were £0 for EM, £83 (£17) for CC and £98 (£31) for IUI. The mean treatment costs per patient for EM, CC and IUI were £12 (£117), £350 (£220) and £331 (£222), respectively. The cost per live birth for EM, CC and IUI was £72 (95% confidence interval £0-£206), £2611 (£1870-£4166) and £1487 (£1116-£2155), respectively. The incremental cost-effectiveness ratio for IUI versus EM was £5604 (-£12204 to £2227), with CC dominated by IUI. CONCLUSIONS: Despite being more expensive, existing treatments such as empirical CC and unstimulated IUI do not offer superior live birth rates compared with EM of unexplained infertility. They are unlikely to be a cost-effective use of limited NHS resources. The study's main limitation is that it did not consider the psychological effects on couples. ISRCT Number: 71762042.

Indirect comparisons of treatments based on systematic reviews of randomised controlled trials.

BACKGROUND: Randomised controlled trials are the most effective way to differentiate between the effects of competing interventions. However, head-to-head studies are unlikely to have been conducted for all competing interventions. AIM: Evaluation of different methodologies used to indirectly compare interventions based on meta analyses of randomised controlled trials. METHODS: Systematic review of Cochrane Database of Systematic Reviews, Cochrane Methodology Register, EMBASE and MEDLINE for reports including meta analyses that contained an indirect comparison. Searching was completed in July 2007. No restriction was placed on language or year of publication. RESULTS: Sixty-two papers identified contained indirect comparisons of treatments. Five different methodologies were employed: comparing point estimates (1/62); comparing 95% confidence intervals (26/62); performing statistical tests on summary estimates (8/62); indirect comparison using a single common comparator (20/62); and mixed treatment comparison (MTC) (7/62). The only methodologies that provide an estimate of the difference between the interventions under consideration and a measure of the uncertainty around that estimate are indirect comparison using a single common comparator and MTC. The MTC might have advantages over other approaches because it is not reliant on a single common comparator and can incorporate the results of direct and indirect comparisons into the analysis. Indirect comparisons require an underlying assumption of consistency of evidence. Utilising any of the methodologies when this assumption is not true can produce misleading results. CONCLUSIONS: Use of either indirect comparison using a common comparator or MTC provides estimates for use in decision making, with the preferred methodology being dependent on the available data.

Clomifene citrate or unstimulated intrauterine insemination compared with expectant management for unexplained infertility: pragmatic randomised controlled trial.

OBJECTIVE: To compare the effectiveness of clomifene citrate and unstimulated intrauterine insemination with expectant management for the treatment of unexplained infertility. DESIGN: Three arm parallel group, pragmatic randomised controlled trial. SETTING: Four teaching hospitals and a district general hospital in Scotland. PARTICIPANTS: Couples with infertility for over two years, confirmed ovulation, patent fallopian tubes, and motile sperm. INTERVENTION: Expectant management, oral clomifene citrate, and unstimulated intrauterine insemination. MAIN OUTCOME MEASURES: The primary outcome was live birth. Secondary outcome measures included clinical pregnancy, multiple pregnancy, miscarriage, and acceptability. RESULTS: 580 women were randomised to expectant management (n=193), oral clomifene citrate (n=194), or unstimulated intrauterine insemination (n=193) for six months. The three randomised groups were comparable in terms of age, body mass index, duration of infertility, sperm concentration, and motility. Live birth rates were 32/193 (17%), 26/192 (14%), and 43/191 (23%), respectively. Compared with expectant management, the odds ratio for a live birth was 0.79 (95% confidence interval 0.45 to 1.38) after clomifene citrate and 1.46 (0.88 to 2.43) after unstimulated intrauterine insemination. More women randomised to clomifene citrate (159/170, 94%) and unstimulated intrauterine insemination (155/162, 96%) found the process of treatment acceptable than those randomised to expectant management (123/153, 80%) (P=0.001 and P<0.001, respectively). CONCLUSION: In couples with unexplained infertility existing treatments such as empirical clomifene and unstimulated intrauterine insemination are unlikely to offer superior live birth rates compared with expectant management. TRIAL REGISTRATION: ISRCT No: 71762042.

Molecular testing for somatic mutations in common cancers: the views of UK oncologists.

BACKGROUND: Somatic mutations are important determinants of cancer behaviour and response to therapy. However, molecular testing in this context has a relatively low profile within the clinical community, despite publicity surrounding targeted therapies such as Herceptin. AIMS: As the testing process affects many stakeholders, especially oncologists, this paper examines current test request patterns and views of such testing. METHODS: A postal questionnaire was mailed to 582 UK oncologists and haematologists, achieving a 20% response rate. RESULTS: The survey revealed that immunohistochemistry and fluorescent in situ hybridisation are the most commonly requested tests (used by 70% and 55% of respondents, respectively), especially for breast cancer. Availability of suitable treatment options is the main factor influencing the decision to test (selected by 62% of respondents). Respondents were generally positive about future demand for immunohistochemistry, fluorescent in situ hybridisation, microarray analysis and DNA-based tests, but uncertain about the prospects for microsatellite instability and ploidy testing. CONCLUSIONS: Overall, respondents thought that somatic mutation testing could have a significant and positive effect on oncology and haematology departments and patient care, especially with better treatment and tumour classification. However, lack of supportive scientific evidence and funding were considered key barriers to widespread testing. Further research is clearly required on both the resource implications of this increase in demand and the best model of service delivery to ensure the most efficient use of health service resources.

Carbapenems versus other beta-lactams in treating severe infections in intensive care: a systematic review of randomised controlled trials.

Carbapenems have not been comprehensively compared in clinical trials with fourth-generation cephalosporins (4GC) and antipseudomonal penicillins (APP) in the treatment of severe infections (SI) and febrile neutropenia (FN). A systematic review of CENTRAL, EMBASE, MEDLINE and JICST-EPlus for randomised controlled trials was conducted to establish the currently available evidence. Database searching was supplemented by hand searching and contacting conference organisers. Searching was completed in November 2006 and no restriction was placed on the language of publication. Data were extracted on clinical response, bacteriologic response, all-cause mortality and adverse events. Of the 265 papers identified, 12 were appropriate for meta-analysis (four 4GC and eight APP). The results showed that carbapenems are associated with a significant reduction in all-cause mortality (relative risk 0.62, 95% confidence interval: 0.41 to 0.95; p=0.03) compared to APP in the treatment of SI, and withdrawals due to adverse events (RR 0.65, 95% CI: 0.45 to 0.96; p=0.03) are also less common. When compared in the treatment of FN, carbapenems are associated with a significant increase in clinical response during the initial 72 h of treatment (RR 1.37, 95% CI: 1.09 to 1.74; p=0.008) and bacteriologic response (RR 1.73, 95% CI: 1.03 to 2.89; p=0.04). For all other outcomes, including all comparisons with 4GC, there were no significant differences between treatments. The use of carbapenems rather than APP could reduce mortality and, by simplifying treatment decisions, reduce the time before patients receive appropriate antibiotic treatment. The currently available evidence is insufficient for distinguishing between carbapenems and 4GC.

Molecular testing for somatic cancer mutations: a survey of current and future testing in UK laboratories.

BACKGROUND: Genetics clinical practice has paid limited attention to non-inherited aspects of cancer, namely mutations occurring during carcinogenesis. These somatic mutations are likely to be the primary determinants of cancer behaviour and treatment response, with a recent example being Her2/Neu gene status and response to Herceptin in breast cancer. AIM: To assess the feasibility of widespread testing of tumours by surveying UK histopathology and genetics laboratories. METHODS: The questionnaire asked: which of the common cancers or other malignancies are routinely assessed; which molecular and cytogenetic methods are used; who orders and funds testing; what is the future demand for somatic testing; and what are the barriers to widespread testing? RESULTS: Of 50 laboratories surveyed, 33 responded, 22 of which are currently using molecular tests. The survey shows that the most common tests are immunohistochemistry, fluorescence in-situ hybridisation and DNA testing of somatic mutations. Most laboratories predict testing will increase over the next 10 years, particularly for DNA testing using microarrays. Respondents perceived the main barriers to expanding molecular testing were a lack of laboratory funding and scientific evidence and testing not considered an NHS priority. CONCLUSION: These results provide important information for healthcare commissioners faced with managing demand for molecular testing of cancers.

Genetic nurse counsellors can be an acceptable and cost-effective alternative to clinical geneticists for breast cancer risk genetic counselling. Evidence from two parallel randomised controlled equivalence trials.

This study compared genetic nurse counsellors with standard services for breast cancer genetic risk counselling services in two regional genetics centres, in Grampian region, North East Scotland and in Cardiff, Wales. Women referred for genetic counselling were randomised to an initial genetic counselling appointment with either a genetic nurse counsellor (intervention) or a clinical geneticist (current service, control). Participants completed postal questionnaires before, immediately after the counselling episode and 6 months later to assess anxiety, general health status, perceived risk and satisfaction. A parallel economic evaluation explored factors influencing cost-effectiveness. The two concurrent randomised controlled equivalence trials were conducted and analysed separately. In the Grampian trial, 289 patients (193 intervention, 96 control) and in the Wales trial 297 patients (197 intervention and 100 control) returned a baseline questionnaire and attended their appointment. Analysis suggested at least likely equivalence in anxiety (the primary outcome) between the two arms of the trials. The cost per counselling episode was 11.54 UK pounds less for nurse-based care in the Grampian trial and 12.50 UK pounds more for nurse-based care in Cardiff. The costs were sensitive to the grade of doctor (notionally) replaced and the extent of consultant supervision required by the nurse. In conclusion, care based on genetic nurse counsellors was not significantly different from conventional cancer genetic services in both trial locations.

Improving the referral process for familial breast cancer genetic counselling: findings of three randomised controlled trials of two interventions.

OBJECTIVES: To evaluate the effectiveness and cost-effectiveness of two complementary interventions, using familial breast cancer as a model condition. The primary care intervention consisted of providing computerised referral guidelines and related education to GPs. The nurse counsellor intervention evaluated genetic nurses as substitutes for specialist geneticists in the initial assessment and management of referred patients. DESIGN: The computerised referral guidelines study was a pragmatic, cluster randomised controlled trial (RCT) with general practices randomised to intervention or control groups. The nurse counsellor intervention was tested in two concurrent RCTs conducted in separate UK health service locations, using predetermined definitions of equivalence. SETTING: The computerised referral guidelines trial took place in general practices in Scotland from November 2000 to June 2001. The nurse counsellor intervention took place in a regional genetics clinic in Scotland, and in two health authorities in Wales served by a single genetics service during 2001. PARTICIPANTS: The computerised referral guidelines study involved GPs and referred patients. Both nurse counsellor intervention trials included women referred for the first time, aged 18 years or over and whose main concern was family history of breast cancer. INTERVENTIONS: The software system was developed with GPs, presenting cancer genetic referral guidelines in a checklist approach. Intervention GPs were invited to postgraduate update education sessions, and both intervention and control practices received paper-based guidelines. The intervention period was November 2000 to June 2001. For the nurse counsellor trial, trial 1 ran outpatient sessions with the same appointment length as the standard service offered by geneticists, but the nurse counsellor saw new patients at the first appointment and referred back to the GP or on to a clinical geneticist according to locally developed protocol, under the supervision of a consultant geneticist. The control intervention was the current service, which comprised an initial and a follow-up appointment with a clinical geneticist. In trial 2, a nurse counsellor ran outpatient sessions with the same appointment length as the new consultant-based cancer genetics service and new patients were seen at the first appointment and referred as in trial 1. The control intervention was a new service, and comprised collection of family history by telephone followed by a consultation with a clinical assistant or a specialist registrar, supervised by a consultant. The intervention was implemented between 1998 and 2001. MAIN OUTCOME MEASURES: In the software system trial, the primary outcome was GPs' confidence in their management of patients with concerns about family history of breast cancer. For the nurse counsellor trial, the primary outcome was patient anxiety, measured using standard scales. RESULTS: In the software system trial, 57 practices (230 GPs) were randomised to the intervention group and 29 (116 GPs) to the control group. No statistically significant differences were detected in GPs' confidence or any other outcomes. Fewer than half of the intervention GPs were aware of the software, and only 22 reported using it in practice. The estimated total cost was GBP3.12 per CD-ROM distributed (2001 prices). For the two arms of the nurse counsellor trial, 289 patients (193 intervention, 96 control) and 297 patients (197 intervention and 100 control) consented, were randomised, returned a baseline questionnaire and attended the clinic for trials 1 and 2 respectively. The analysis in both cases suggested equivalence in all anxiety scores, and no statistically significant differences were detected in other outcomes in either trial. A cost-minimisation analysis suggested that the cost per counselling episode was GBP10.23 lower in intervention arm than in the control arm and GBP10.89 higher in the intervention arm than in the control arm (2001 prices) for trials 1 and 2, respectively. Taking the trials together, the costs were sensitive to the grades of doctors and the time spent in consultant supervision of the nurse counsellor, but they were only slightly affected by the grade of nurse counsellor, the selected discount rate and the lifespan of equipment. CONCLUSIONS: Computer-based systems in the primary care intervention cannot be recommended for widespread use without further evaluation and testing in real practice settings. Genetic nurse counsellors may be a cost-effective alternative to assessment by doctors. This trial does not provide definitive evidence that the general policy of employing genetics nurse counsellors is sound, as it was based on only three individuals. Future evaluations of computer-based decision support systems for primary care must first address their efficacy under ideal conditions, identify barriers to the use of such systems in practice, and provide evidence of the impact of the policy of such systems in routine practice. The nurse counsellor trial should be replicated in other settings to provide reassurance of the generalisability of the intervention and other models of nurse-based assessment, such as in outreach clinics, should be developed and evaluated. The design of future evaluations of professional substitution should also address issues such as the effect of different levels of training and experience of nurse counsellors, and learning effects.