Tracy E Roberts

Screening to prevent spontaneous preterm birth: systematic reviews of accuracy and effectiveness literature with economic modelling

OBJECTIVES To identify combinations of tests and treatments to predict and prevent spontaneous preterm birth. DATA SOURCES Searches were run on the following databases up to September 2005 inclusive: MEDLINE, EMBASE, DARE, the Cochrane Library (CENTRAL and Cochrane Pregnancy and Childbirth Group trials register) and MEDION. We also contacted experts including the Cochrane Pregnancy and Childbirth Group and checked reference lists of review articles and papers that were eligible for inclusion. REVIEW METHODS Two series of systematic reviews were performed: (1) accuracy of tests for the prediction of spontaneous preterm birth in asymptomatic women in early pregnancy and in women symptomatic with threatened preterm labour in later pregnancy; (2) effectiveness of interventions with potential to reduce cases of spontaneous preterm birth in asymptomatic women in early pregnancy and to reduce spontaneous preterm birth or improve neonatal outcome in women with a viable pregnancy symptomatic of threatened preterm labour. For the health economic evaluation, a model-based analysis incorporated the combined effect of tests and treatments and their cost-effectiveness. RESULTS Of the 22 tests reviewed for accuracy, the quality of studies and accuracy of tests was generally poor. Only a few tests had LR+ > 5. In asymptomatic women these were ultrasonographic cervical length measurement and cervicovaginal prolactin and fetal fibronectin screening for predicting spontaneous preterm birth before 34 weeks. In this group, tests with LR- < 0.2 were detection of uterine contraction by home uterine monitoring and amniotic fluid C-reactive protein (CRP) measurement. In symptomatic women with threatened preterm labour, tests with LR+ > 5 were absence of fetal breathing movements, cervical length and funnelling, amniotic fluid interleukin-6 (IL-6), serum CRP for predicting birth within 2-7 days of testing, and matrix metalloprotease-9, amniotic fluid IL-6, cervicovaginal fetal fibronectin and cervicovaginal human chorionic gonadotrophin (hCG) for predicting birth before 34 or 37 weeks. In this group, tests with LR- < 0.2 included measurement of cervicovaginal IL-8, cervicovaginal hCG, cervical length measurement, absence of fetal breathing movement, amniotic fluid IL-6 and serum CRP, for predicting birth within 2-7 days of testing, and cervicovaginal fetal fibronectin and amniotic fluid IL-6 for predicting birth before 34 or 37 weeks. The overall quality of the trials included in the 40 interventional topics reviewed for effectiveness was also poor. Antibiotic treatment was generally not beneficial but when used to treat bacterial vaginosis in women with intermediate flora it significantly reduced the incidence of spontaneous preterm birth. Smoking cessation programmes, progesterone, periodontal therapy and fish oil appeared promising as preventative interventions in asymptomatic women. Non-steroidal anti-inflammatory agents were the most effective tocolytic agent for reducing spontaneous preterm birth and prolonging pregnancy in symptomatic women. Antenatal corticosteroids had a beneficial effect on the incidence of respiratory distress syndrome and the risk of intraventricular haemorrhage (28-34 weeks), but the effects of repeat courses were unclear. For asymptomatic women, costs ranged from 1.08 pounds for vitamin C to 1219 pounds for cervical cerclage, whereas costs for symptomatic women were more significant and varied little, ranging from 1645 pounds for nitric oxide donors to 2555 pounds for terbutaline; this was because the cost of hospitalisation was included. The best estimate of additional average cost associated with a case of spontaneous preterm birth was approximately 15,688 pounds for up to 34 weeks and 12,104 pounds for up to 37 weeks. Among symptomatic women there was insufficient evidence to draw firm conclusions for preventing birth at 34 weeks. Hydration given to women testing positive for amniotic fluid IL-6 was the most cost-effective test-treatment combination. Indomethacin given to all women without any initial testing was the most cost-effective option for preventing birth before 37 weeks among symptomatic women. For a symptomatic woman, the most cost-effective test-treatment combination for postponing delivery by at least 48 h was the cervical length (15 mm) measurement test with treatment with indomethacin for all those testing positive. This combination was also the most cost-effective option for postponing delivery by at least 7 days. Antibiotic treatment for asymptomatic bacteriuria of all women without any initial testing was the most cost-effective option for preventing birth before 37 weeks among asymptomatic women but this does not take into account the potential side effects of antibiotics or issues such as increased resistance. CONCLUSIONS For primary prevention, an effective, affordable and safe intervention applied to all mothers without preceding testing is likely to be the most cost-effective approach in asymptomatic women in early pregnancy. For secondary prevention among women at risk of preterm labour in later pregnancy, a management strategy based on the results of testing is likely to be more cost-effective. Implementation of a treat-all strategy with simple interventions, such as fish oils, would be premature for asymptomatic women. Universal provision of high-quality ultrasound machines in labour wards is more strongly indicated for predicting spontaneous preterm birth among symptomatic women than direct management, although staffing issues and the feasibility and acceptability to mothers and health providers of such strategies need to be explored. Further research should include investigations of low-cost and effective tests and treatments to reduce and delay spontaneous preterm birth and reduce the risk of perinatal mortality arising from preterm birth.

A randomised controlled trial of the clinical effectiveness and cost-effectiveness of the levonorgestrel-releasing intrauterine system in primary care against standard treatment for menorrhagia: the ECLIPSE trial.

BACKGROUND Heavy menstrual bleeding (HMB) is a common problem, yet evidence to inform decisions about initial medical treatment is limited. OBJECTIVES To assess the clinical effectiveness and cost-effectiveness of the levonorgestrel-releasing intrauterine system (LNG-IUS) (Mirena®, Bayer) compared with usual medical treatment, with exploration of womens perspectives on treatment. DESIGN A pragmatic, multicentre randomised trial with an economic evaluation and a longitudinal qualitative study. SETTING Women who presented in primary care. PARTICIPANTS A total of 571 women with HMB. A purposeful sample of 27 women who were randomised or ineligible owing to treatment preference participated in semistructured face-to-face interviews around 2 and 12 months after commencing treatment. INTERVENTIONS LNG-IUS or usual medical treatment (tranexamic acid, mefenamic acid, combined oestrogen-progestogen or progesterone alone). Women could subsequently swap or cease their allocated treatment. OUTCOME MEASURES The primary outcome was the patient-reported score on the Menorrhagia Multi-Attribute Scale (MMAS) assessed over a 2-year period and then again at 5 years. Secondary outcomes included general quality of life (QoL), sexual activity, surgical intervention and safety. Data were analysed using iterative constant comparison. A state transition model-based cost-utility analysis was undertaken alongside the randomised trial. Quality-adjusted life-years (QALYs) were derived from the European Quality of Life-5 Dimensions (EQ-5D) and the Short Form questionnaire-6 Dimensions (SF-6D). The intention-to-treat analyses were reported as cost per QALY gained. Uncertainty was explored by conducting both deterministic and probabilistic sensitivity analyses. RESULTS The MMAS total scores improved significantly in both groups at all time points, but were significantly greater for the LNG-IUS than for usual treatment [mean difference over 2 years was 13.4 points, 95% confidence interval (CI) 9.9 to 16.9 points; p < 0.001]. However, this difference between groups was reduced and no longer significant by 5 years (mean difference in scores 3.9 points, 95% CI -0.6 to 8.3 points; p = 0.09). By 5 years, only 47% of women had a LNG-IUS in place and 15% were still taking usual medical treatment. Five-year surgery rates were low, at 20%, and were similar, irrespective of initial treatments. There were no significant differences in serious adverse events between groups. Using the EQ-5D, at 2 years, the relative cost-effectiveness of the LNG-IUS compared with usual medical treatment was £1600 per QALY, which by 5 years was reduced to £114 per QALY. Using the SF-6D, usual medical treatment dominates the LNG-IUS. The qualitative findings show that womens experiences and expectations of medical treatments for HMB vary considerably and change over time. Women had high expectations of a prompt effect from medical treatments. CONCLUSIONS The LNG-IUS, compared with usual medical therapies, resulted in greater improvement over 2 years in womens assessments of the effect of HMB on their daily routine, including work, social and family life, and psychological and physical well-being. At 5 years, the differences were no longer significant. A similar low proportion of women required surgical intervention in both groups. The LNG-IUS is cost-effective in both the short and medium term, using the method generally recommended by the National Institute for Health and Care Excellence. Using the alternative measures to value QoL will have a considerable impact on cost-effectiveness decisions. It will be important to explore the clinical and health-care trajectories of the ECLIPSE (clinical effectiveness and cost-effectiveness of levonorgestrel-releasing intrauterine system in primary care against standard treatment for menorrhagia) trial participants to 10 years, by which time half of the cohort will have reached menopause. TRIAL REGISTRATION Current Controlled Trials ISRCTN86566246. FUNDING This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 88. See the NIHR Journals Library website for further project information.

Positron emission tomography/computerised tomography imaging in detecting and managing recurrent cervical cancer: systematic review of evidence, elicitation of subjective probabilities and economic modelling

BACKGROUND Cancer of the uterine cervix is a common cause of mortality in women. After initial treatment women may be symptom free, but the cancer may recur within a few years. It is uncertain whether it is more clinically effective to survey asymptomatic women for signs of recurrence or to await symptoms or signs before using imaging. OBJECTIVES This project compared the diagnostic accuracy of imaging using positron emission tomography/computerised tomography (PET-CT) with that of imaging using CT or magnetic resonance imaging (MRI) alone and evaluated the cost-effectiveness of adding PET-CT as an adjunct to standard practice. DATA SOURCES Standard systematic review methods were used to obtain and evaluate relevant test accuracy and effectiveness studies. Databases searched included MEDLINE, EMBASE, Science Citation Index and The Cochrane Library. All databases were searched from inception to May 2010. REVIEW METHODS Study quality was assessed using appropriately modified Quality Assessment of Diagnostic Accuracy Studies (QUADAS) criteria. Included were any studies of PET-CT, MRI or CT compared with the reference standard of histopathological findings or clinical follow-up in symptomatic women suspected of having recurrent or persistent cervical cancer and in asymptomatic women a minimum of 3 months after completion of primary treatment. Subjective elicitation of expert opinion was used to supplement diagnostic information needed for the economic evaluation. The effectiveness of treatment with chemotherapy, radiotherapy, chemoradiotherapy, radical hysterectomy and pelvic exenteration was systematically reviewed. Meta-analysis was carried out in RevMan 5.1 (The Cochrane Collaboration, The Nordic Cochrane Centre, Copenhagen, Denmark) and Stata version 11 (StataCorp LP, College Station, Texas, USA). A Markov model was developed to compare the relative cost-effectiveness using TreeAge Pro software version 2011 (TreeAge Software Inc., Evanston, IL, USA). RESULTS For the diagnostic review, a total of 7524 citations were identified, of which 12 test accuracy studies were included in the review: six studies evaluated PET-CT, two evaluated MRI, three evaluated CT and one evaluated both MRI and CT. All studies were small and the majority evaluated imaging in women in whom recurrence was suspected on the basis of symptoms. The PET-CT studies evaluated local and distant recurrence and most used methods similar to current practice, whereas five of the six CT and MRI studies evaluated local recurrence only and not all employed currently used methods. Meta-analysis of PET-CT studies gave a sensitivity of 92.2% [95% confidence interval (CI) 85.1% to 96.0%] and a specificity of 88.1% (95% CI 77.9% to 93.9%). MRI sensitivities and specificities varied between 82% and 100% and between 78% and 100%, respectively, and CT sensitivities and specificities varied between 78% and 93% and between 0% and 95%, respectively. One small study directly compared PET-CT with older imaging methods and showed more true-positives and fewer false-negatives with PET-CT. The subjective elicitation from 21 clinical experts gave test accuracy results for asymptomatic and symptomatic women and the results for symptomatic women were similar to those from the published literature. Their combined opinions also suggested that the mean elicited increase in accuracy from the addition of PET-CT to MRI and/or CT was less than the elicited minimum important difference in accuracy required to justify the routine addition of PET-CT for the investigation of women after completion of primary treatment. For the effectiveness review, a total of 24,943 citations were identified, of which 62 studies were included (chemotherapy, 19 randomised controlled trials; radiotherapy or chemoradiotherapy, 16 case series; radical hysterectomy and pelvic exenteration, 27 case series). None provided the effectiveness of cisplatin monotherapy, the most commonly used chemotherapeutic agent in the NHS, compared with supportive care in a background of other treatment such as radiotherapy in recurrent and persistent cervical cancer. The model results showed that adding PET-CT to the current treatment strategy of clinical examination, MRI and/or CT scan was significantly more costly with only a minimal increase in effectiveness, with incremental cost-effectiveness ratios for all models being > £1M per quality-adjusted life-year (QALY) and the additional cost per additional case of recurrence being in the region of £600,000. LIMITATIONS There was considerable uncertainty in many of the parameters used because of a lack of good-quality evidence in recurrent or persistent cervical cancer. The evidence on diagnostic and therapeutic impact incorporated in the economic model was poor and there was little information on surveillance of asymptomatic women. CONCLUSIONS Given the current evidence available, the addition of PET-CT to standard practice was not found to be cost-effective in the diagnosis of recurrent or persistent cervical cancer. However, although probabilistic sensitivity analysis showed that the main conclusion about cost-ineffectiveness of PET-CT was firm given the range of assumptions made, should more reliable information become available on accuracy, therapeutic impact and effectiveness, and the cost of PET-CT reduce, this conclusion may need revision. Current guidelines recommending imaging for diagnosis using expensive methods such as PET-CT need to be reconsidered in the light of the above. FUNDING The National Institute for Health Research Health Technology Assessment programme.

Stillbirths: economic and psychosocial consequences.

Despite the frequency of stillbirths, the subsequent implications are overlooked and underappreciated. We present findings from comprehensive, systematic literature reviews, and new analyses of published and unpublished data, to establish the effect of stillbirth on parents, families, health-care providers, and societies worldwide. Data for direct costs of this event are sparse but suggest that a stillbirth needs more resources than a livebirth, both in the perinatal period and in additional surveillance during subsequent pregnancies. Indirect and intangible costs of stillbirth are extensive and are usually met by families alone. This issue is particularly onerous for those with few resources. Negative effects, particularly on parental mental health, might be moderated by empathic attitudes of care providers and tailored interventions. The value of the baby, as well as the associated costs for parents, families, care providers, communities, and society, should be considered to prevent stillbirths and reduce associated morbidity.

Hysterectomy, endometrial ablation, and levonorgestrel releasing intrauterine system (Mirena) for treatment of heavy menstrual bleeding: cost effectiveness analysis

Objective To undertake a cost effectiveness analysis comparing first and second generation endometrial ablative techniques, hysterectomy, and the levonorgestrel releasing intrauterine system (Mirena) for treating heavy menstrual bleeding. Design Model based economic evaluation with data from an individual patient data meta-analysis supplemented with cost and outcome data from published sources taking an NHS (National Health Service) perspective. A state transition (Markov) model was developed, the structure being informed by the reviews of the trials and clinical input. A subgroup analysis, one way sensitivity analysis, and probabilistic sensitivity analysis were also carried out. Population Four hypothetical cohorts of women with heavy menstrual bleeding. Interventions One of four alternative strategies: Mirena, first or second generation endometrial ablation techniques, or hysterectomy. Main outcome measures Cost effectiveness based on incremental cost per quality adjusted life year (QALY). Results Hysterectomy is the preferred strategy for the first intervention for heavy menstrual bleeding. Although hysterectomy is more expensive, it produces more QALYs relative to other remaining strategies and is likely to be considered cost effective. The incremental cost effectiveness ratio for hysterectomy compared with Mirena is £1440 (€1633,

Hysterectomy, endometrial ablation and Mirena® for heavy menstrual bleeding: a systematic review of clinical effectiveness and cost-effectiveness analysis

2350) per additional QALY. The incremental cost effectiveness ratio for hysterectomy compared with second generation ablation is £970 per additional QALY. Conclusion In light of the acceptable thresholds used by the National Institute for Health and Clinical Excellence, hysterectomy would be considered the preferred strategy for the treatment of heavy menstrual bleeding. The results concur with those of other studies but are highly sensitive to utility values used in the analysis.

Screening for Chlamydia trachomatis: a systematic review of the economic evaluations and modelling

OBJECTIVE The aim of this project was to determine the clinical effectiveness and cost-effectiveness of hysterectomy, first- and second-generation endometrial ablation (EA), and Mirena® (Bayer Healthcare Pharmaceuticals, Pittsburgh, PA, USA) for the treatment of heavy menstrual bleeding. DESIGN Individual patient data (IPD) meta-analysis of existing randomised controlled trials to determine the short- to medium-term effects of hysterectomy, EA and Mirena. A population-based retrospective cohort study based on record linkage to investigate the long-term effects of ablative techniques and hysterectomy in terms of failure rates and complications. Cost-effectiveness analysis of hysterectomy versus first- and second-generation ablative techniques and Mirena. SETTING Data from women treated for heavy menstrual bleeding were obtained from national and international trials. Scottish national data were obtained from the Scottish Information Services Division. PARTICIPANTS Women who were undergoing treatment for heavy menstrual bleeding were included. INTERVENTIONS Hysterectomy, first- and second-generation EA, and Mirena. MAIN OUTCOME MEASURES Satisfaction, recurrence of symptoms, further surgery and costs. RESULTS Data from randomised trials indicated that at 12 months more women were dissatisfied with first-generation EA than hysterectomy [odds ratio (OR): 2.46, 95% confidence interval (CI) 1.54 to 3.93; p = 0.0002), but hospital stay [WMD (weighted mean difference) 3.0 days, 95% CI 2.9 to 3.1 days; p < 0.00001] and time to resumption of normal activities (WMD 5.2 days, 95% CI 4.7 to 5.7 days; p < 0.00001) were longer for hysterectomy. Unsatisfactory outcomes associated with first- and second-generation techniques were comparable [12.2% (123/1006) vs 10.6% (110/1034); OR 1.20, 95% CI 0.88 to 1.62; p = 0.2). Rates of dissatisfaction with Mirena and second-generation EA were similar [18.1% (17/94) vs 22.5% (23/102); OR 0.76, 95% CI 0.38 to 1.53; p = 0.4]. Indirect estimates suggested that hysterectomy was also preferable to second-generation EA (OR 2.32, 95% CI 1.27 to 4.24; p = 0.006) in terms of patient dissatisfaction. The evidence to suggest that hysterectomy is preferable to Mirena was weaker (OR 2.22, 95% CI 0.94 to 5.29; p = 0.07). In women treated by EA or hysterectomy and followed up for a median [interquartile range (IQR)] duration of 6.2 (2.7-10.8) and 11.6 (7.9-14.8) years, respectively, 962/11,299 (8.5%) women originally treated by EA underwent further gynaecological surgery. While the risk of adnexal surgery was similar in both groups [adjusted hazards ratio 0.80 (95% CI 0.56 to 1.15)], women who had undergone ablation were less likely to need pelvic floor repair [adjusted hazards ratio 0.62 (95% CI 0.50 to 0.77)] and tension-free vaginal tape surgery for stress urinary incontinence [adjusted hazards ratio 0.55 (95% CI 0.41 to 0.74)]. Abdominal hysterectomy led to a lower chance of pelvic floor repair surgery [hazards ratio 0.54 (95% CI 0.45 to 0.64)] than vaginal hysterectomy. The incidence of endometrial cancer following EA was 0.02%. Hysterectomy was the most cost-effective treatment. It dominated first-generation EA and, although more expensive, produced more quality-adjusted life-years (QALYs) than second-generation EA and Mirena. The incremental cost-effectiveness ratios for hysterectomy compared with Mirena and hysterectomy compared with second-generation ablation were £1440 per additional QALY and £970 per additional QALY, respectively. CONCLUSIONS Despite longer hospital stay and time to resumption of normal activities, more women were satisfied after hysterectomy than after EA. The few data available suggest that Mirena is potentially cheaper and more effective than first-generation ablation techniques, with rates of satisfaction that are similar to second-generation techniques. Owing to a paucity of trials, there is limited evidence to suggest that hysterectomy is preferable to Mirena. The risk of pelvic floor surgery is higher in women treated by hysterectomy than by ablation. Although the most cost-effective strategy, hysterectomy may not be considered an initial option owing to its invasive nature and higher risk of complications. Future research should focus on evaluation of the clinical effectivesness and cost-effectiveness of the best second-generation EA technique under local anaesthetic versus Mirena and types of hysterectomy such as laparoscopic supracervical hysterectomy versus conventional hysterectomy and second-generation EA. FUNDING The National Institute for Health Research Health Technology Assessment programme.

Partner notification of chlamydia infection in primary care: randomised controlled trial and analysis of resource use

Objective: To review systematically and critically, evidence used to derive estimates of costs and cost effectiveness of chlamydia screening. Methods: Systematic review. A search of 11 electronic bibliographic databases from the earliest date available to August 2004 using keywords including chlamydia, pelvic inflammatory disease, economic evaluation, and cost. We included studies of chlamydia screening in males and/or females over 14 years, including studies of diagnostic tests, contact tracing, and treatment as part of a screening programme. Outcomes included cases of chlamydia identified and major outcomes averted. We assessed methodological quality and the modelling approach used. Results: Of 713 identified papers we included 57 formal economic evaluations and two cost studies. Most studies found chlamydia screening to be cost effective, partner notification to be an effective adjunct, and testing with nucleic acid amplification tests, and treatment with azithromycin to be cost effective. Methodological problems limited the validity of these findings: most studies used static models that are inappropriate for infectious diseases; restricted outcomes were used as a basis for policy recommendations; and high estimates of the probability of chlamydia associated complications might have overestimated cost effectiveness. Two high quality dynamic modelling studies found opportunistic screening to be cost effective but poor reporting or uncertainty about complication rates make interpretation difficult. Conclusion: The inappropriate use of static models to study interventions to prevent a communicable disease means that uncertainty remains about whether chlamydia screening programmes are cost effective or not. The results of this review can be used by health service managers in the allocation of resources, and health economists and other researchers who are considering further research in this area.

Pulse oximetry as a screening test for congenital heart defects in newborn infants: a cost-effectiveness analysis

Abstract Objective To evaluate the effectiveness of a practice nurse led strategy to improve the notification and treatment of partners of people with chlamydia infection. Design Randomised controlled trial. Setting 27 general practices in the Bristol and Birmingham areas. Participants 140 men and women with chlamydia (index cases) diagnosed by screening of a home collected urine sample or vulval swab specimen. Interventions Partner notification at the general practice immediately after diagnosis by trained practice nurses, with telephone follow up by a health adviser; or referral to a specialist health adviser at a genitourinary medicine clinic. Main outcome measures Primary outcome was the proportion of index cases with at least one treated sexual partner. Specified secondary outcomes included the number of sexual contacts elicited during a sexual history, positive test result for chlamydia six weeks after treatment, and the cost of each strategy in 2003 sterling prices. Results 65.3% (47/72) of participants receiving practice nurse led partner notification had at least one partner treated compared with 52.9% (39/68) of those referred to a genitourinary medicine clinic (risk difference 12.4%, 95% confidence interval −1.8% to 26.5%). Of 68 participants referred to the clinic, 21 (31%) did not attend. The costs per index case were £32.55 for the practice nurse led strategy and £32.62 for the specialist referral strategy. Conclusion Practice based partner notification by trained nurses with telephone follow up by health advisers is at least as effective as referral to a specialist health adviser at a genitourinary medicine clinic, and costs the same. Trial registration Clinical trials: NCT00112255.

Public involvement in health care priority setting: an economic perspective

Objective To undertake a cost-effectiveness analysis that compares pulse oximetry as an adjunct to clinical examination with clinical examination alone in newborn screening for congenital heart defects (CHDs). Design Model-based economic evaluation using accuracy and cost data from a primary study supplemented from published sources taking an NHS perspective. Setting Six large maternity units in the UK. Patients 20 055 newborn infants prior to discharge from hospital. Intervention Pulse oximetry as an adjunct to clinical examination. Main outcome measure Cost effectiveness based on incremental cost per timely diagnosis. Results Pulse oximetry as an adjunct to clinical examination is twice as costly but provides a timely diagnosis to almost 30 additional cases of CHD per 100 000 live births compared with a modelled strategy of clinical examination alone. The incremental cost-effectiveness ratio for this strategy compared with clinical examination alone is approximately £24 000 per case of timely diagnosis in a population in which antenatal screening for CHDs already exists. The probabilistic sensitivity analysis suggests that at a willingness-to-pay (WTP) threshold of £100 000, the probability of ‘pulse oximetry as an adjunct to clinical examination’ being cost effective is more than 90%. Such a WTP threshold is plausible if a newborn with timely diagnosis of a CHD gained just five quality-adjusted life years, even when treatment costs are taken into consideration. Conclusion Pulse oximetry as an adjunct to current routine practice of clinical examination alone is likely to be considered a cost-effective strategy in the light of currently accepted thresholds.