Displaced risk. Keeping mothers and babies safe: a UK ambulance service lens

Aim

The aim of this professional practice paper is to provide a critical commentary on displaced risk among perinatal and neonatal patients attended to by the ambulance service.

Background

NHS services across the United Kingdom are currently facing unprecedented demand and increased scrutiny in their ability to provide safe and personalised care to patients. While current focus in the system centres around addressing social care demand, hospital bed capacity, planned care waiting times, staffing and ambulance handover delays, a less explored cohort of patients impacted by the current healthcare crisis is perinatal and neonatal populations attended to by the ambulance service. Little focus has been paid within national agendas to the care provided to women and babies outside of planned maternity and obstetric care. A case is presented to highlight the importance of considering urgent and emergency maternity care provision provided by the ambulance service, and the impact of 'displaced risk' due to the current pressures within healthcare systems.

Conclusion

Placed in a national context, drawing upon current independent reviews into maternity services, national transformation agendas and the most recent MBRRACE-UK confidential enquiry into maternal deaths and morbidity, a case is made to commissioners and Integrated Care Systems to focus on and invest in the unplanned pre-hospital care of maternity and neonatal patients. Recognition of the ambulance service as a key provider of care to this cohort of patients is paramount, calling on services and systems to work together on realising and addressing displaced risk for perinatal populations across the United Kingdom. A system approach that acknowledges the need for high-quality care at every point of contact and equitability in access to services for pregnant, postpartum and neonatal patients is vital.

Midwifery: home and away

The challenges faced by birthing women and maternity healthcare professionals in developing countries cannot not be over estimated. The experience of a midwife in a rural Tanzanian hospital described in this article gives a small insight into these challenges. With intermittent electricity, no running water, three beds, 20 births per day and lack of midwifery or obstetric education, morbidity and mortality rates are high, and teaching is difficult. Conversely, where monitoring is minimalistic and time limits are not applied, 'normal birth' is truly the norm and the trust in women to grow and birth their babies is consistent and commendable. Reflection upon midwifery in developing countries can help inform attitudes and practice in the UK.

Changing practice: physiological cord clamping

Every baby deserves the best start to life. Receiving the full quota of blood from the placenta directly after birth has profound short and long-term benefits for the baby; these have been extensively researched and documented. This article discusses a student midwife's experience of participating in reviewing third stage guidelines to incorporate this growing evidence base into clinical practice within a large London NHS Trust. A new local guideline (unpublished) recommends every baby (where clinically possible) has the opportunity to benefit from 'physiological cord clamping'. The aim of the article is to inspire midwives and student midwives to become involved with similar activities within their own trusts.

The clinical effectiveness and cost-effectiveness of rituximab for the first-line treatment of chronic lymphocytic leukaemia: an evidence review of the submission from Roche

This paper presents a summary of the evidence review group (ERG) report into the clinical effectiveness and cost-effectiveness of rituximab for the first-line treatment of chronic lymphocytic leukaemia (CLL) based upon a review of the manufacturer's submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The manufacturer's searches for clinical effectiveness and cost-effectiveness data were appropriate and included all relevant studies. The submission's evidence came from a single, unpublished, well-conducted randomised controlled trial (RCT) comparing rituximab in combination with fludarabine and cyclophosphamide (R-FC) with fludarabine and cyclophosphamide (FC) alone for the first-line treatment of CLL. There was a statistically significant increase in progression-free survival (PFS) with R-FC compared with FC alone {median 39.8 months vs 32.2 months; hazard ratio [HR] 0.56 [95% confidence interval (CI) 0.43 to 0.72]}. However, the initial significant treatment benefit for R-FC compared with FC for overall survival was not maintained at a slightly longer follow-up time [median 25.4 months; adjusted HR 0.72 (95% CI 0.48 to 1.09)]. Response rates, numbers of patients with event-free survival and duration of response all favoured treatment with R-FC. Additional evidence from a mixed-treatment comparison model indicated R-FC to be significantly superior to chlorambucil alone for both PFS and overall and complete response rates. The incidence of grade 3 or 4 adverse events was higher in the R-FC arm (77%) than in the FC arm (62%). Dose modifications were also more frequent in this arm, but this did not lead to differences in treatment discontinuation. Roche used a three-state Markov model (PFS, progressed and death) to model the cost-effectiveness of R-FC compared with FC and chlorambucil alone. The model used a cycle length of 1 month and a lifetime time horizon. The approach taken to modelling was reasonable and the sources and justification of estimates were generally sound. The base-case analysis produced an incremental cost-effectiveness ratio (ICER) of 13,189 pounds per quality-adjusted life-year (QALY) for R-FC versus FC, and 6422 pounds per QALY for the comparison of R-FC versus chlorambucil, suggesting that R-FC is cost-effective at normal willingness-to-pay thresholds. One-way sensitivity analyses produced a range of ICERs from 10,249 pounds to 22,661 pounds per QALY for R-FC versus FC, and 5612 pounds and 6921 pounds per QALY for R-FC versus chlorambucil. Probabilistic sensitivity analysis results matched the deterministic results very closely. However, the sensitivity analysis did not fully investigate the uncertainty associated with differential values across arms or with the structural assumptions of the model, and utility values were not drawn from an empirical study. The NICE guidance issued as a result of the STA states that: Rituximab in combination with fludarabine and cyclophosphamide (R-FC) is recommended as an option for the first-line treatment of chronic lymphocytic leukaemia in people for whom fludarabine in combination with cyclophosphamide (FC) is considered appropriate. Rituximab in combination with chemotherapy agents other than fludarabine and cyclophosphamide is not recommended for the first-line treatment of chronic lymphocytic leukaemia.

Computerised decision support systems in order communication for diagnostic, screening or monitoring test ordering: systematic reviews of the effects and cost-effectiveness of systems

BACKGROUND

Order communication systems (OCS) are computer applications used to enter diagnostic and therapeutic patient care orders and to view test results. Many potential benefits of OCS have been identified including improvements in clinician ordering patterns, optimisation of clinical time, and aiding communication processes between clinicians and different departments. Many OCS now include computerised decision support systems (CDSS), which are information systems designed to improve clinical decision-making. CDSS match individual patient characteristics to a computerised knowledge base, and software algorithms generate patient-specific recommendations.

OBJECTIVES

To investigate which CDSS in OCS are in use within the UK and the impact of CDSS in OCS for diagnostic, screening or monitoring test ordering compared to OCS without CDSS. To determine what features of CDSS are associated with clinician or patient acceptance of CDSS in OCS and what is known about the cost-effectiveness of CDSS in diagnostic, screening or monitoring test OCS compared to OCS without CDSS.

DATA SOURCES

A generic search to identify potentially relevant studies for inclusion was conducted using MEDLINE, EMBASE, Cochrane Controlled Trials Register (CCTR), CINAHL (Cumulative Index to Nursing and Allied Health Literature), DARE (Database of Abstracts of Reviews of Effects), Health Technology Assessment (HTA) database, IEEE (Institute of Electrical and Electronic Engineers) Xplore digital library, NHS Economic Evaluation Database (NHS EED) and EconLit, searched between 1974 and 2009 with a total of 22,109 titles and abstracts screened for inclusion.

REVIEW METHODS

CDSS for diagnostic, screening and monitoring test ordering OCS in use in the UK were identified through contact with the 24 manufacturers/suppliers currently contracted by the National Project for Information Technology (NpfIT) to provide either national or specialist decision support. A generic search to identify potentially relevant studies for inclusion in the review was conducted on a range of medical, social science and economic databases. The review was undertaken using standard systematic review methods, with studies being screened for inclusion, data extracted and quality assessed by two reviewers. Results were broadly grouped according to the type of CDSS intervention and study design where possible. These were then combined using a narrative synthesis with relevant quantitative results tabulated.

RESULTS

Results of the studies included in review were highly mixed and equivocal, often both within and between studies, but broadly showed a beneficial impact of the use of CDSS in conjunction with OCS over and above OCS alone. Overall, if the findings of both primary and secondary outcomes are taken into account, then CDSS significantly improved practitioner performance in 15 out of 24 studies (62.5%). Only two studies covered the cost-effectiveness of CDSS: a Dutch study reported a mean cost decrease of 3% for blood tests orders (639 euros) in each of the intervention clinics compared with a 2% (208 euros) increase in control clinics in test costs; and a Spanish study reported a significant increase in the cost of laboratory tests from 41.8 euros per patient per annum to 47.2 euros after implementation of the system.

LIMITATIONS

The response rate from the survey of manufacturers and suppliers was extremely low at only 17% and much of the feedback was classified as being commercial-in-confidence (CIC). No studies were identified which assessed the features of CDSS that are associated with clinician or patient acceptance of CDSS in OCS in the test ordering process and only limited data was available on the cost-effectiveness of CDSS plus OCS compared with OCS alone and the findings highly specific. Although CDSS appears to have a potentially small positive impact on diagnostic, screening or monitoring test ordering, the majority of studies come from a limited number of institutions in the USA.

CONCLUSIONS

If the findings of both primary and secondary outcomes are taken into account then CDSS showed a statistically significant benefit on either process or practitioner performance outcomes in nearly two-thirds of the studies. Furthermore, in four studies that assessed adverse effects of either test cancellation or delay, no significant detrimental effects in terms of additional utilisation of health-care resources or adverse events were observed. We believe the key current need is for a well designed and comprehensive survey, and on the basis of the results of this potentially for evaluation studies in the form of cluster randomised controlled trials or randomised controlled trials which incorporate process, and patient outcomes, as well as full economic evaluations alongside the trials to assess the impact of CDSS in conjunction with OCS versus OCS alone for diagnostic, screening or monitoring test ordering in the NHS. The economic evaluation should incorporate the full costs of potentially developing, testing, and installing the system, including staff training costs.

STUDY REGISTRATION

Study registration 61.

The clinical effectiveness and cost-effectiveness of rituximab for the first-line treatment of chronic lymphocytic leukaemia: an evidence review of the submission from Roche

This paper presents a summary of the evidence review group (ERG) report into the clinical effectiveness and cost-effectiveness of rituximab for the first-line treatment of chronic lymphocytic leukaemia (CLL) based upon a review of the manufacturer’s submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The manufacturer’s searches for clinical effectiveness and cost-effectiveness data were appropriate and included all relevant studies. The submission’s evidence came from a single, unpublished, well-conducted randomised controlled trial (RCT) comparing rituximab in combination with fludarabine and cyclophosphamide (R-FC) with fludarabine and cyclophosphamide (FC) alone for the first-line treatment of CLL. There was a statistically significant increase in progression-free survival (PFS) with R-FC compared with FC alone {median 39.8 months vs 32.2 months; hazard ratio [HR] 0.56 [95% confidence interval (CI) 0.43 to 0.72]}. However, the initial significant treatment benefit for R-FC compared with FC for overall survival was not maintained at a slightly longer follow-up time [median 25.4 months; adjusted HR 0.72 (95% CI 0.48 to 1.09)]. Response rates, numbers of patients with event-free survival and duration of response all favoured treatment with R-FC. Additional evidence from a mixed-treatment comparison model indicated R-FC to be significantly superior to chlorambucil alone for both PFS and overall and complete response rates. The incidence of grade 3 or 4 adverse events was higher in the R-FC arm (77%) than in the FC arm (62%). Dose modifications were also more frequent in this arm, but this did not lead to differences in treatment discontinuation. Roche used a three-state Markov model (PFS, progressed and death) to model the cost-effectiveness of R-FC compared with FC and chlorambucil alone. The model used a cycle length of 1 month and a lifetime time horizon. The approach taken to modelling was reasonable and the sources and justification of estimates were generally sound. The base-case analysis produced an incremental cost-effectiveness ratio (ICER) of £13,189 per quality-adjusted life-year (QALY) for R-FC versus FC, and £6422 per QALY for the comparison of R-FC versus chlorambucil, suggesting that R-FC is cost-effective at normal willingness-to-pay thresholds. One-way sensitivity analyses produced a range of ICERs from £10,249 to £22,661 per QALY for R-FC versus FC, and £5612 and £6921 per QALY for R-FC versus chlorambucil. Probabilistic sensitivity analysis results matched the deterministic results very closely. However, the sensitivity analysis did not fully investigate the uncertainty associated with differential values across arms or with the structural assumptions of the model, and utility values were not drawn from an empirical study. The NICE guidance issued as a result of the STA states that: Rituximab in combination with fludarabine and cyclophosphamide (R-FC) is recommended as an option for the first-line treatment of chronic lymphocytic leukaemia in people for whom fludarabine in combination with cyclophosphamide (FC) is considered appropriate.  Rituximab in combination with chemotherapy agents other than fludarabine and cyclophosphamide is not recommended for the first-line treatment of chronic lymphocytic leukaemia.

Surgical procedures and non-surgical devices for the management of non-apnoeic snoring: a systematic review of clinical effects and associated treatment costs

OBJECTIVES

To review the evidence on the clinical effects and associated treatment costs of surgical procedures and non-surgical devices for the management of non-apnoeic snoring.

DATA SOURCES

Major electronic databases were searched for relevant studies published between 1980 and 2007. All treatment costs were estimated based on data from NHS reference costs, device manufacturers and clinical opinion.

REVIEW METHODS

Studies were screened, data extracted and quality assessed according to standard methods. Results were broadly grouped according to the intervention and comparator when applicable, and further subgrouped according to the specific intervention type and study design. Results were combined using a narrative synthesis with relevant quantitative results tabulated. Differences between studies assessing the same intervention were explored narratively by examining differences in the intervention, study duration and study quality.

RESULTS

The systematic review included 27 studies (three randomised controlled trials, two controlled clinical trials and 22 pre-post studies) reported in 30 publications assessing uvulopalatopharyngoplasty (UP3) versus laser-assisted uvulopalatoplasty (LAUP), UP3 alone, LAUP alone, palatal stiffening techniques (Pillar implants and injection snoreplasty), radiofrequency ablation (RFA) of the soft palate or tongue base, continuous positive airway pressure (CPAP) devices and mandibular advancement splints (MAS). Studies were generally of a low methodological quality with small sample sizes. A total of 1191 patients was included. Both UP3 and LAUP reduced the number of snores per hour and produced a modest reduction in snoring loudness. UP3 was effective in reducing a number of subjectively reported snoring indices, but results on objective measures were equivocal. Limited evidence indicates that subjectively assessed snoring is improved after LAUP; no objective measures were assessed. RFA was associated with a reduction in partner-assessed snoring intensity, though evidence for an objective reduction in snoring sound levels was mixed. Pillar implants were moderately effective at reducing partner-rated snoring intensity, but had no effect on objective snoring indices. Use of CPAP reduced the number of snores per hour; no subjective measures were evaluated. Use of MAS improved objective snoring outcomes, including the maximal snoring sound volume, the mean snoring sound volume and the percentage of time spent in loud snoring; no subjective measures were evaluated. The cost for UP3 ranges from approximately 1230 pounds to approximately 1550 pounds. For LAUP the cost varies from 790 pounds to 2070 pounds depending on the number of stages of the procedure. The treatment costs associated with the use of Pillar implants range from 1110 pounds to 1160 pounds. The approximate annual treatment costs associated with the use of a CPAP machine and MAS are 220 pounds and 130 pounds respectively.

CONCLUSIONS

This study highlighted the paucity and poor quality of the evidence available on the effects of both surgical procedures and non-surgical devices for the management of primary snoring. Any conclusions to be drawn from the results are therefore somewhat tentative. There was no procedure that was clearly the least-cost option. Further research should focus on standardising methods of measuring outcomes and reporting, undertaking active controlled trials, and investigating the longer-term effects of treatments.

Should men with asymptomatic non-specific urethritis be identified and treated?

There is currently a debate as to whether microscopy is necessary in asymptomatic men presenting for a sexual health screen. Arguments favouring microscopy include finding chlamydia in a significant proportion of sexual partners of men with non-specific urethritis (NSU) in studies that included symptomatic men. We aimed to investigate the proportion of partners of men with asymptomatic NSU who were diagnosed with a sexually transmitted infection. A retrospective case-note review was carried out for all men diagnosed with asymptomatic pathogen-negative NSU, and their traced sexual contacts, during a nine-month period. As a result of contact-tracing, we identified 42 partners who attended the clinic. Only one partner (2.4%) tested positive for chlamydia. A further two partners were diagnosed with a viral sexually transmitted infection (STI). The low level of chlamydia and other STIs in partners of asymptomatic men with pathogen-negative NSU does not support the routine use of microscopy to identify these patients.

Systematic review and economic analysis of the comparative effectiveness of different inhaled corticosteroids and their usage with long-acting beta2 agonists for the treatment of chronic asthma in children under the age of 12 years

OBJECTIVES

To assess the clinical and cost-effectiveness of inhaled corticosteroids (ICS) alone and ICS used in combination with a long-acting beta2 agonist (LABA) in the treatment of chronic asthma in children aged under 12 years.

DATA SOURCES

Major electronic bibliographic databases, e.g. MEDLINE and EMBASE, were searched up to February/March 2006 (and updated again in October 2006).

REVIEW METHODS

A systematic review of clinical and cost-effectiveness studies and economic analyses were carried out. A flexible framework was used to allow different types of economic analyses as appropriate, with either a cost comparison or cost-consequence comparison conducted.

RESULTS

Of 5175 records identified through systematic literature searching, 34 records describing 25 studies were included (16 were fully published randomised controlled trials, six were systematic reviews, and three were post-2004 conference abstracts). The most frequently reported relevant outcomes in the 16 RCTs were peak expiratory flow rate (13 trials), FEV1 (13 trials), symptoms (13 trials), adverse events or exacerbations (13 trials), use of rescue medication (12 trials), markers of adrenal function (e.g. blood or urine cortisol concentrations) (13 trials), height and/or growth rate (seven trials) and markers of bone metabolism (two trials). In the trials that compared low-dose ICS versus ICS and high-dose ICS versus ICS, no consistent significant differences or patterns in differential treatment effect among the outcomes were evident. Where differences were statistically significant at high doses, such as for lung function and growth, they favoured formoterol fumarate (FF), but this was generally in studies that did not compare the ICS at the accepted clinically equivalent doses. Differences between the drugs in impact on adrenal suppression were only significant in two studies. At doses of 200, 400 and 800 microg/day, beclometasone dipropionate (BDP) appears to be the current cheapest ICS product both with the inclusion and exclusion of chlorofluorocarbon (CFC)-propelled products. In the trials comparing ICS at a higher dose with ICS and LABA in combination, most outcomes favoured the combined inhaler. Only the combination inhaler, Seretide Evohaler, is slightly cheaper than the weighted mean cost of all types of ICS at increased dose except BDP 400 microg/day (including CFC-propelled products). Both the combination inhalers, Seretide Accuhaler and Symbicort Turbohaler, are more expensive than the weighted mean cost for all types of ICS at a two-fold increased dose. Compared with the lowest cost preparation for each ICS drug, all the combination inhalers are always more expensive than the ICS products at increased dose.

CONCLUSIONS

The limited evidence available indicates that there are no consistent significant differences in effectiveness between the three ICS licensed for use in children at either low or high dose. BDP CFC-propelled products are often the cheapest ICS currently available at both low and high dose, and may remain so even when CFC-propelled products are excluded. Exclusion of CFC-propelled products increases the mean annual cost of all budesonide (BUD) and BDP, while the overall cost differences between the comparators diminish. There is very limited evidence available for the efficacy and safety of ICS and LABAs in children. From this limited evidence, there appear to be no significant clinical differences in effects between the use of a combination inhaler versus the same drugs in separate inhalers. There is a lack of evidence comparing ICS at a higher dose with ICS and LABA in combination and comparing the combination products with each other. In the absence of any evidence concerning the effectiveness of ICS at higher dose with ICS and LABA, a cost-consequence analysis gives mixed results. There are potential cost savings with the use of combination inhalers compared to separate inhalers. At present prices, the BUD/FF combination is more expensive than those containing FP/SAL, but it is not known whether there are clinically significant differences between them. A scoping review is required to assess the requirements for additional primary research on the clinical effectiveness of treatment for asthma in children under 5 years old. Such a review could also usefully include all treatment options, pharmacological and non-pharmacological, for asthma. A direct head-to-head trial that compares the two combination therapies of FP/SAL and BUD/FF is warranted, and it is important to assess whether the addition of a LABA to a lower dose of ICS could potentially be as effective as an increased dose of ICS alone, but also be steroid sparing. There is also a need for the long-term adverse events associated with ICS use to be assessed systematically. Future trials of treatment for chronic asthma in children should aim to standardise further the way in which outcome measures are defined. There should be a greater focus on patient-centred outcomes to provide a more meaningful estimation of the impact of treatment on asthma control. Methods of reporting also require standardisation.

Systematic review and economic analysis of the comparative effectiveness of different inhaled corticosteroids and their usage with long-acting beta2 agonists for the treatment of chronic asthma in adults and children aged 12 years and over

OBJECTIVES

To assess the clinical and cost-effectiveness of inhaled corticosteroids (ICS) alone and ICS used in combination with a long-acting beta2 agonist (LABA) in the treatment of chronic asthma in adults and children aged over 12 years.

DATA SOURCES

Major electronic bibliographic databases, e.g. MEDLINE and EMBASE, were searched up to February/March 2006 (and updated again in October 2006).

REVIEW METHODS

A systematic review of clinical and cost-effectiveness studies was conducted. Cost comparison and cost-consequence analyses were performed where appropriate.

RESULTS

The assessment of clinical effectiveness was based on the 67 randomised controlled trials selected from the 5175 reports identified through the systematic literature search. The most frequently reported relevant outcomes were lung function, symptoms, use of rescue medication and adverse events. The trials varied considerably. In the trials that compared low-dose ICS versus ICS and high-dose ICS versus ICS, there were few significant differences in clinical effectiveness, although a few of the trials had assessed non-inferiority between the comparators rather than superiority. At doses of 400, 800 and 'high-level' doses of 1500 or 1600 microg/day, beclometasone dipropionate (BDP) appears to be the current cheapest ICS product both with the inclusion and exclusion of chlorofluorocarbon (CFC)-propelled products. A significant treatment benefit for combination ICS/LABA therapy across a range of outcomes compared with ICS alone was identified [when the ICS was double the accepted clinically equivalent dose of the ICS in the combination inhaler, and dry powder inhalers (DPIS) were used to deliver the drugs]. When a formoterol fumarate (FF)/salmeterol (SAL) combination inhaler and a budesonide (BUD)/FF combination inhaler were each compared with their constituent drugs delivered in separate inhalers, there were very few statistically significant differences between the treatments across the various efficacy outcomes and the rate of adverse events. Combination inhalers were more often cheaper than doubling the dose of ICS alone. However, the costs were highly variable and dependent on both the dose required and the preparation used in the trials. The estimated mean annual cost of FP/SAL combination varied from being 94 pounds cheaper to 109 pounds more expensive than the alternative of BUD at a higher dose. The BUD/FF combination varied from being 163 pounds cheaper to 66 pounds more expensive than the higher dose of either BUD or FP. When the combination inhalers were compared to each other, the results were mixed, with the FP/SAL combination significantly superior on some outcomes and the BUD/FF combination superior on others; however, meta-analysis showed that there were no significant differences between the two treatments in the rate of adverse events. Taking an ICS with a LABA as either of the two currently available combination products, FP/SAL and BUD/FF, is usually cheaper than taking the relevant constituent drugs in separate inhalers. At very high doses of BUD (1600 microg/day), however, the BUD/FF combination inhaler can be up to 156 pounds more expensive than having the same drugs in separate inhalers. In terms of the relative costs associated with taking one of the combination inhalers, at low dose (400 microg BUD or 200 microg FP/day) the cheapest combination inhaler is FP/SAL as a pressurised metered dose inhaler (pMDI) (Seretide Evohaler). However, this is only slightly cheaper than using BUD/FF as a DPI (Symbicort Turbohaler). At higher dose levels (800 microg BUD or 500 microg FP/day) FP/SAL as either pMDI aerosol (Seretide Evohaler) or a DPI (Seretide Accuhaler) is the cheapest combination product available, but again only slightly cheaper than the DPI BUD/FF combination (Symbicort Turbohaler). It should be highlighted, however, that the three head-to-head trials that compared the effects of FP/SAL with BUD/FF used the FP/SAL DPI combination inhaler, Seretide Accuhaler.

CONCLUSIONS

The evidence indicates that there are few consistent significant differences in effects between the five ICS licensed for use in adults and adolescents over the age of 12 years, at either low or high dose. On average, BDP products currently tend to be the cheapest ICS available and tend to remain so as the daily ICS dose required increases. There is evidence that the addition of a LABA to an ICS is potentially more clinically effective than doubling the dose of ICS alone, although consistent significant differences between the two treatment strategies are not observed for all outcome measures. The cost differences between combination therapy compared with ICS monotherapy are highly variable and dependent on the dose required and the particular preparations used. For the combination therapies of ICS/LABA there are potential cost savings with the use of combination inhalers compared with separate inhalers, with few differences between the two treatment strategies in terms of effects. The only exception to this cost saving is with BUD/FF at doses higher than 1200 microg/day, where separate inhaler devices can become equivalent to or cheaper than combination inhalers. Neither of the two combination inhalers (FP/SAL or BUD/FF) is consistently superior in terms of treatment effect. A comparison of the costs associated with each combination therapy indicates that at low dose FP/SAL delivered via a pMDI is currently the cheapest combination inhaler but only marginally cheaper than BUD/FF delivered as a DPI. At higher doses, both the FP/SAL combination inhalers (PMDI and DPI) are marginally cheaper than BUD/FF (DPI). Future trials of treatment for chronic asthma should standardise the way in which outcome measures are defined and measured, with a greater focus on patient-centred outcomes. For informing future cost-utility and cost-effectiveness analyses from a UK NHS perspective, there is a need for longitudinal studies that comprehensively track the care pathways followed when people experience asthma exacerbations of different severity. Further research synthesis, quantifying the adverse effects of the different ICS, is required for treatment choices by patients and clinicians to be fully informed.

Topotecan, pegylated liposomal doxorubicin hydrochloride and paclitaxel for second-line or subsequent treatment of advanced ovarian cancer: a systematic review and economic evaluation

OBJECTIVES

To examine the clinical effectiveness and cost-effectiveness of intravenous formulations of topotecan monotherapy, pegylated liposomal doxorubicin hydorocholoride (PLDH) monotherapy and paclitaxel used alone or in combination with a platinum-based compound for the second-line or subsequent treatment of advanced ovarian cancer.

DATA SOURCES

Electronic databases covering publication years 2000-4. Company submissions.

REVIEW METHODS

Seventeen databases were searched for randomised controlled trials (RCTs) and systematic reviews for the clinical effectiveness of PLDH, topotecan and paclitaxel and economic evaluations of the cost-effectiveness of PLDH, topotecan and paclitaxel. Selected studies were quality assessed and data extracted, as were the three company submissions. A new model was developed to assess the costs of the alternative treatments, the differential mean survival duration and the impact of health-related quality of life. Monte-Carlo simulation was used to reflect uncertainty in the cost-effectiveness results.

RESULTS

Nine RCTs were identified. In five of these trials, both the comparators were used within their licensed indications. Of these five, three included participants with both platinum-resistant and platinum-sensitive advanced ovarian cancer, and a further two only included participants with platinum-sensitive disease. The comparators that were assessed in the three trials that included both subtypes of participants were PLDH versus topotecan, topotecan versus paclitaxel and PLDH versus paclitaxel. In the further two trials that included participants with the subtype of platinum-sensitive disease, the comparators that were assessed were single-agent paclitaxel versus a combination of cyclophosphamide, doxorubicin and cisplatin (CAP) and paclitaxel plus platinum-based chemotherapy versus conventional platinum-based therapy alone. A further four trials were identified and included in the review in which one of the comparators in the trial was used outside its licensed indication. The comparators assessed in these trials were oxaliplatin versus paclitaxel, paclitaxel given weekly versus every 3 weeks, paclitaxel at two different dose levels and oral versus intravenous topotecan. Four studies met the inclusion criteria for the cost-effectiveness review. The review of the economic evidence from the literature and industry submissions identified a number of significant limitations in existing studies assessing the cost-effectiveness of PLDH, topotecan and paclitaxel. Analysis 1 assessed the cost-effectiveness of PLDH, topotecan and paclitaxel administered as monotherapies. Sensitivity analysis was undertaken to explore the impact of patient heterogeneity (e.g. platinum-sensitive and platinum-resistant/refractory patients), the inclusion of additional trial data and alternative assumptions regarding treatment and monitoring costs. In the base-case results for Analysis 1, paclitaxel monotherapy emerged as the cheapest treatment. When the incremental cost-effectiveness ratios (ICERs) were estimated, topotecan was dominated by PLDH. Hence the options considered in the estimation of the ICERs were paclitaxel and PLDH. The ICER for PLDH compared with paclitaxel was pound 7033 per quality-adjusted life-year (QALY) in the overall patient population (comprising platinum-sensitive, -refractory and -resistant patients). The ICER was more favourable in the platinum-sensitive group ( pound 5777 per QALY) and less favourable in the platinum-refractory/resistant group ( pound 9555 per QALY). The cost-effectiveness results for the base-case analysis were sensitive to the inclusion of additional trial data. Incorporating the results of the additional trial data resulted in less favourable estimates for the ICER for PLDH versus paclitaxel compared with the base-case results. The ICER of PLDH compared with paclitaxel was pound 20,620 per QALY in the overall patient population, pound 16,183 per QALY in the platinum-sensitive population and pound 26,867 per QALY in the platinum-resistant and -refractory population. The results from Analysis 2 explored the cost-effectiveness of the full range of treatment comparators for platinum-sensitive patients. The treatment options considered in this model comprised PLDH, topotecan, paclitaxel-monotherapy, CAP, paclitaxel/platinum combination therapy and platinum monotherapy. Owing to the less robust approaches that were employed to synthesise the available evidence and the heterogeneity between the different trials, the reliability of these results should be interpreted with some caution. Topotecan, paclitaxel monotherapy and PLDH were all dominated by platinum monotherapy (i.e. higher costs and lower QALYs). After excluding these alternatives, the treatments that remained under consideration were platinum monotherapy, CAP and paclitaxel-platinum combination therapy. Of these three alternatives, platinum monotherapy was the least costly and least effective. The ICER for CAP compared with platinum monotherapy was pound 16,421 per QALY. The ICER for paclitaxel-platinum combination therapy compared with CAP was pound 20,950 per QALY.

CONCLUSIONS

For participants with platinum-resistant disease there was a low probability of response to treatment with PLDH, topotecan or paclitaxel. Furthermore, there was little difference between the three comparators in relation to overall survival. The comparators did, however, differ considerably in their toxicity profiles. Given the low survival times and response rates, it appears that the maintenance of quality of life and the control of symptoms and toxicity are paramount in this patient group. As the three comparators differed significantly in terms of their toxicity profiles, patient and physician choice is also an important element that should be addressed when decisions are made regarding second-line therapy. It can also be suggested that this group of patients may benefit from being included in further clinical trials of new drugs. For participants with platinum-sensitive disease there was a considerable range of median survival times observed across the trials. The most favourable survival times and response rates were observed for paclitaxel and platinum combination therapy. This suggests that treatment with combination therapy may be more beneficial than treatment with a single-agent chemotherapeutic regimen. In terms of single-agent compounds, the evidence suggests that PLDH is more effective than topotecan. Evidence from a further trial that compared PLDH and paclitaxel suggests that there is no significant difference between these two comparators in this trial. The three comparators did, however, differ significantly in terms of their toxicity profiles across the trials. Although treatment with PLDH may therefore be more beneficial than that with topotecan, patient and physician choice as to the potential toxicities associated with each of the comparators and the patient's ability and willingness to tolerate these are of importance. Assuming the NHS is willing to pay up to pound 20,000-40,000 per additional QALY, PLDH appears to be cost-effective compared with topotecan and paclitaxel monotherapy, in terms of the overall patient population and the main subgroups considered. The cost-effectiveness results for the base-case analysis were sensitive to the inclusion of additional trial data. Incorporating the results of additional trial data gave less favourable estimates for the ICER for PLDH versus paclitaxel monotherapy, compared with the base-case results. Although the ICER of PLDH compared with paclitaxel monotherapy was less favourable, PLDH was still cost-effective compared with topotecan and paclitaxel monotherapy. For platinum-sensitive patients, the combination of paclitaxel and platinum appears to be cost-effective. On the strength of the evidence reviewed here, it can be suggested that participants with platinum-resistant disease may benefit from being included in further clinical trials of new drugs. To assess the effectiveness of combination therapy against a single-agent non-platinum-based compound, it can be suggested that a trial that compared paclitaxel in combination with a platinum-based therapy versus single-agent PLDH would be a reasonable option.

Clinical effectiveness and cost-effectiveness of clopidogrel and modified-release dipyridamole in the secondary prevention of occlusive vascular events: a systematic review and economic evaluation

OBJECTIVES

To examine the clinical effectiveness and cost-effectiveness of two alternative antiplatelet agents, clopidogrel and modified-release (MR)-dipyridamole, relative to prophylactic doses of aspirin for the secondary prevention of occlusive vascular events.

DATA SOURCES

Electronic databases.

REVIEW METHODS

A total of 2906 titles and abstracts were rigorously screened and 441 studies were assessed in detail. Two RCTs were identified. For the assessment of cost-effectiveness, eight reviews were identified. The results were presented in structured tables and as a narrative summary. No additional clinical effectiveness data were presented in either of two company submissions. All economic evaluations (including accompanying models) included in the company submissions were assessed. Following this analysis, if the existing models (company or published) were not sufficient, a de novo model or modified versions of the models were developed.

RESULTS

In the CAPRIE trial the point estimate for the primary outcome, i.e. ischaemic stroke, myocardial infarction (MI) or vascular death, favoured clopidogrel over aspirin, but the boundaries of the confidence intervals raise the possibility that clopidogrel is not more beneficial than aspirin. In terms of the secondary outcomes reported, there was a non-significant trend in favour of clopidogrel over aspirin but the boundaries of the confidence intervals on the relative risks all crossed unity. There was no difference in the number of patients ever reporting any bleeding disorder in the clopidogrel group compared with the aspirin group. The incidences of rash and diarrhoea were statistically significantly higher in the clopidogrel group than the aspirin group. Patients in the aspirin group had a higher incidence of indigestion/nausea/vomiting than patients in the clopidogrel group. Haematological adverse events were rare in both the clopidogrel and aspirin groups. No cases of thrombotic thrombocytopenic purpura were reported in either group. Treatment with MR-dipyridamole alone did not significantly reduce the risk of any of the primary outcomes reported in ESPS-2 compared with treatment with aspirin. ASA-MR-dipyridamole was significantly more effective than aspirin alone in patients with stroke or transient ischaemic attacks (TIAs) at reducing the outcome of stroke and marginally more effective at reducing stroke and/or death. Treatment with ASA-MR-dipyridamole did not statistically significantly reduce the risk of death compared to treatment with aspirin. The number of strokes was statistically significantly reduced in the ASA-MR-dipyridamole group compared with the MR-dipyridamole group. In terms of the other primary outcomes, stroke and/or death and death, the results favoured treatment with ASA-MR-dipyridamole but the findings were not statistically significant. There was no difference in the number of bleeding complications between the ASA-MR-dipyridamole and aspirin groups. The incidence of bleeding complications was significantly lower in the MR-dipyridamole treatment group. More patients in the MR-dipyridamole treatment groups experienced headaches compared to patients receiving treatment with aspirin alone. The York model assessed the cost-effectiveness of differing combinations of treatment strategies in four patient subgroups, under a number of different scenarios. The results of the model were sensitive to the assumptions made in the alternative scenarios, in particular the impact of therapy on non-vascular deaths.

CONCLUSIONS

Clopidogrel was marginally more effective than aspirin at reducing the risk of ischaemic stroke, MI or vascular death in patients with atherosclerotic vascular disease, however, it did not statistically significantly reduce the risk of vascular death or death from any cause compared with aspirin. There was no statistically significant difference in the number of bleeding complications experienced in the clopidogrel and aspirin groups. MR-dipyridamole in combination with aspirin was superior to aspirin alone at reducing the risk of stroke and marginally more effective at reducing the risk of stroke and/or death. Compared with treatment with MR-dipyridamole alone, MR-dipyridamole in combination with aspirin significantly reduced the risk of stroke. Treatment with MR-dipyridamole in combination with aspirin did not statistically significantly reduce the risk of death compared with aspirin. Compared with treatment with MR-dipyridamole alone, bleeding complications were statistically significantly higher in patients treated with aspirin and MR-dipyridamole in combination with aspirin. Due to the assumptions that have to be made, no conclusions could be drawn about the relative effectiveness of MR-dipyridamole, alone or in combination with aspirin, and clopidogrel from the adjusted indirect comparison. The following would apply for a cost of up to GBP20,000-40,000 per additional quality-adjusted life-year. For the stroke and TIA subgroups, ASA-MR-dipyridamole would be the most cost-effective therapy given a 2-year treatment duration as long as all patients were not left disabled by their initial (qualifying) stroke. For a lifetime treatment duration, ASA-MR-dipyridamole would be considered more cost-effective than aspirin as long as treatment effects on non-vascular deaths are not considered and all patients were not left disabled by their initial stroke. In patients left disabled by their initial stroke, aspirin is the most cost-effective therapy. Clopidogrel and MR-dipyridamole alone would not be considered cost-effective under any scenario. For the MI and peripheral arterial disease subgroups, clopidogrel would be considered cost-effective for a treatment duration of 2 years. For a lifetime treatment duration, clopidogrel would be considered more cost-effective than aspirin as long as treatment effects on non-vascular deaths are not considered. It is suggested that the combination of clopidogrel and aspirin should be evaluated for the secondary prevention of occlusive vascular events. Also randomised, direct comparisons of clopidogrel and MR-dipyridamole in combination with aspirin are required to inform the treatment of patients with a history of stroke and TIA, plus trials that compare treatment with clopidogrel and MR-dipyridamole for the secondary prevention of vascular events in patients who demonstrate a genuine intolerance to aspirin.

Clopidogrel used in combination with aspirin compared with aspirin alone in the treatment of non-ST-segment-elevation acute coronary syndromes: a systematic review and economic evaluation

OBJECTIVES

To review systematically the clinical effectiveness and the cost-effectiveness of clopidogrel used in combination with standard therapy including aspirin, compared with standard therapy alone for the treatment of non-ST-segment elevation acute coronary syndromes (ACS).

DATA SOURCES

Electronic databases. Manufacturers' submissions.

REVIEW METHODS

Studies were selected using rigorous criteria. The quality of randomised controlled trials (RCTs) was assessed according to criteria based on NHS CRD Report No. 4, and the quality of systematic reviews was assessed according to the guidelines for the Database of Reviews of Effect (DARE) criteria. The quality of economic evaluations was assessed according to a specifically tailored checklist. The clinical effectiveness and cost-effectiveness of clopidogrel in combination with standard therapy compared with standard therapy alone were synthesised through a narrative review with full tabulation of the results of the included studies. In the economic evaluations, a cost-effectiveness model was constructed using the best available evidence to determine cost-effectiveness in a UK setting.

RESULTS

One RCT (the CURE trial) was a randomised, double-blind, placebo-controlled trial of high quality and showed that clopidogrel in addition to aspirin was significantly more effective than placebo plus aspirin in patients with non-ST-segment elevation ACS for the composite outcome of death from cardiovascular causes, non-fatal myocardial infarction or stroke over the 9-month treatment period. However, clopidogrel was associated with a significantly higher number of episodes of both major and minor bleeding. The results from the five systematic reviews that assessed the adverse events associated with long-term aspirin use showed that aspirin was associated with a significantly higher incidence of haemorrhagic stroke, extracranial haemorrhage and gastrointestinal haemorrhage compared with placebo. Of the cost-effectiveness evidence reviewed, only the manufacturer's submission was considered relevant from the perspective of the NHS. The review of this evidence highlighted potential limitations within the submission in its use of data and in the model structure used. These limitations led to the development of a new model with the aim of providing a more reliable estimate of the cost-effectiveness from the perspective of the UK NHS. This model indicated that clopidogrel appears cost-effective compared with standard care alone in patients with non-ST-elevation ACS as long as the NHS is willing to pay GBP6078 per quality of life year (QALY). The results were most sensitive to the inclusion of additional strategies that assessed alternative treatment durations with clopidogrel. Although treatment with clopidogrel for 12 months remained cost-effective for the overall cohort, provisional findings indicate that the shorter treatment durations may be more cost-effective in patients at low risk.

CONCLUSIONS

The results of the CURE trial indicate that clopidogrel in combination with aspirin was significantly more effective than placebo combined with aspirin in a wide range of patients with ACS. This benefit was largely related to a reduction in Q-wave myocardial infarction. There was no statistically significant benefit in relation to mortality. The trial data suggested that a substantial part of the benefit derived from clopidogrel is achieved by 3 months, with a further small benefit over the remaining 9 months of chronic treatment. The results from the base-case model suggest that treatment with clopidogrel as an adjunct to standard therapy (including aspirin) for 12 months, compared with standard therapy alone, is cost-effective in non-ST elevation ACS patients as long as the health service is willing to pay GBP6078 per additional QALY. However, although treatment with clopidogrel for 12 months remained cost-effective for the overall cohort, provisional findings indicate that the shorter treatment durations may be more cost-effective in patients at low risk. To estimate the exact length of time that clopidogrel in addition to standard therapy should be prescribed for patients with non-ST-segment ACS would require a prospective trial that randomised patients to various durations of therapy. This would accurately assess whether a 'rebound' phenomenon occurs in patients if clopidogrel were stopped after 3 months of treatment.

Size-dependent absorption and defect states in CdSe nanocrystals in various multilayer structures

GeS2-CdSe superlattices and composite films are prepared by consecutive thermal evaporation of CdSe and GeS2 in vacuum. CdSe layer thickness varies between 1 and 10 nm, while the thickness of GeS2 layers is either equal (in superlattices) to or 20 times greater (in composite films) than that of CdSe layers. Standard spectral photocurrent measurements and various constant photocurrent methods are used to study optical absorption of all samples. An overall blueshift is observed with decreasing CdSe layer thickness of superlattices. This shift is related to a size-induced increase of the optical band gap of CdSe due to one-dimensional carrier confinement in the continuous nanocrystalline CdSe layers. A number of features are observed in the absorption spectra of composite films containing CdSe nanocrystals with average radii of approximately 2.5 and approximately 3.3 nm. They are discussed in terms of three-dimensional carrier confinement and are considered a manifestation of excited electron states in CdSe nanocrystals embedded in GeS2 thin film matrix. In addition to these discrete features, the exponential dependence of the optical absorption (Urbach) edge indicates a distribution of "valence band" tail states associated with disorder. Transient photoconductivity measurements made on similarly prepared SiOx-CdSe superlattices exhibit a rapid fall in photocurrent by a power law decay over several orders of magnitude of time, which is consistent with multi-pletrapping transport via an extensive distribution of deep defects.

THE BEHAVIOURAL RESPONSE TO WHIPLASH INJURY

We studied 50 consecutive patients presenting at an accident department after rear-end vehicle collisions and recorded symptoms and psychological test scores within one week of injury, at three months and at two years. The range of neck movement was noted at three months.

Within one week of injury, psychological test scores were normal in 82% of the group but became abnormal in 81% of the patients with intrusive or disabling symptoms at over three months (p < 0.001) and remained abnormal in 69% at two years. The clinical outcome after two years could be predicted at three months with 76% accuracy by neck stiffness, 74% by psychological score and 82% by a combination of these variables.

The severity of symptoms after a whiplash injury is related both to the physical restriction of neck movement and to psychological disorder. The latter becomes established within three months of the injury.

The behavioural response to whiplash injury

We studied 50 consecutive patients presenting at an accident department after rear-end vehicle collisions and recorded symptoms and psychological test scores within one week of injury, at three months and at two years. The range of neck movement was noted at three months. Within one week of injury, psychological test scores were normal in 82% of the group but became abnormal in 81% of the patients with intrusive or disabling symptoms at over three months (p < 0.001) and remained abnormal in 69% at two years. The clinical outcome after two years could be predicted at three months with 76% accuracy by neck stiffness, 74% by psychological score and 82% by a combination of these variables. The severity of symptoms after a whiplash injury is related both to the physical restriction of neck movement and to psychological disorder. The latter becomes established within three months of the injury.

Human recombinant interleukin 1 beta suppresses acetylcholine release from rat myenteric plexus

BACKGROUND

A marked suppression of acetylcholine (ACh) release from myenteric nerves in the inflamed intestine of rats infected by Trichinella spiralis has been shown. In this model, there is increased expression of interleukin 1 beta (IL-1 beta) in the myenteric plexus. Therefore, the ability of IL-1 beta to alter ACh release in longitudinal muscle-myenteric plexus (LMMP) preparations from noninfected rats was examined.

METHODS

LMMP preparations were loaded with [3H]choline before stimulation by KCl or electrical field stimulation. ACh release was recorded by measuring 3H in the superfusate. Experiments were performed in the presence or absence of human recombinant IL-1 beta.

RESULTS

IL-1 beta had no immediate effect on the basal or stimulated release of ACh. A marked suppression of ACh release was observed in tissues that had been preincubated with IL-1 beta for 60 minutes or more. The effect of IL-1 beta was concentration and time dependent with maximum suppression occurring with 10 ng/mL of the cytokine after a 90-minute incubation. The action of human recombinant (hr) IL-1 beta was abolished by boiling the cytokine for 20 minutes and was prevented by preincubating the cytokine with neutralizing antibody. The IL-1 beta effect was also blocked by cycloheximide and was spontaneously reversible after 60 minutes.

CONCLUSION

It was concluded that IL-1 beta suppresses ACh release via the formation and release of a protein mediator that could be another cytokine, including IL-1. Based on these findings, we consider IL-1 beta a putative mediator of the changes in cholinergic nerve function observed in the inflamed rat intestine.

Immunomodulatory effects of interferon-gamma in patients with metastatic malignant melanoma

Interferon-gamma (IFN-gamma) is a potent monocyte/macrophage activating agent that in animal models exhibits a bell-shaped dose-response curve of immunomodulatory activity and antitumor efficacy. Previous clinical trials of IFN-gamma conducted at the maximal tolerated dose (MTD) have been associated with low response rates that may have been due to failure to treat at an optimal immunomodulatory dose (OID). The objective of this study was to test the hypothesis that optimal immunomodulatory activity of IFN-gamma in patients with metastatic melanoma would be obtained at a dose below the MTD. Groups of five patients each were given daily subcutaneous injections of IFN-gamma at doses of 0.01, 0.1, or 0.25 mg/m2. In vivo immunomodulation was assessed by serial measurement of serum neopterin and by flow cytometry. IFN-gamma doses of 0.1 or 0.25 mg/m2 induced significantly greater immunomodulation of monocyte-associated immune parameters than 0.01 mg/m2. Changes in immunologic parameters included marked elevation of serum neopterin levels, significant increases in monocyte expression of CD64, beta 2-microglobulin, and HLA-ABC, and decreased monocyte expression of CD14. The most dramatic decreases in CD14 expression were observed on monocytes obtained from patients treated at 0.25 mg/m2. The 0.25-mg/m2 dose group had significantly lower white blood cell counts on day 14. No bell-shaped curve of immunologic response was observed over the dosage range tested. Based on the similarity of the immunologic effects at 0.1 and 0.25 mg/m2, treatment at the MTD of IFN-gamma (0.25 mg/m2) represents treatment at the OID for patients with metastatic malignant melanoma.

Effect of inflammation of enteric nerves. Cytokine-induced changes in neurotransmitter content and release

The results of our previously published work provide evidence of inflammation-induced functional disturbances in the enteric nervous system. Data presented in this paper describe our preliminary results indicating that the altered function in enteric nerves in the nematode-infected rat model of intestinal inflammation is mediated by interleukin-1. This is based on the ability of the exogenous cytokine to mimic changes observed in the model, and on the ability of a specific IL-1 antagonist to attenuate these changes. In addition, we have identified mechanisms underlying the actions of IL-1 in the myenteric plexus. Our data are consistent with a direct interaction between the cytokine and neural membranes. In addition, the delayed effect of IL-1 beta on neurotransmitter release appears to be due to the release of endogenous IL-1, most likely from macrophage-like cells in the myenteric plexus (Fig. 3). If such cells possess receptors for neuropeptides, as has been found with macrophages elsewhere in the gut, a neuroimmune axis would exist in the myenteric plexus. Thus, the finding of a source of IL-1 in the plexus of the noninflamed intestine invites speculation on a neuromodulatory role of the cytokine within the enteric nervous system.

Antioxidant therapy for recurrent pancreatitis: placebo-controlled trial

Oxidant stress has been proposed as the initiating pathogenetic mechanism in pancreatitis, hence micronutrient antioxidant therapy has been assessed in patients with recurrent attacks and/or constant pancreatic pain. In a 20-week double-blind double-dummy crossover trial active treatment was given as two types of tablets providing daily doses of 600 micrograms organic selenium, 9000 IU beta carotene, 0.54 g vitamin C, 270 IU vitamin E and 2 g methionine. Of 28 patients enrolled, 20 adhered to the full protocol (idiopathic chronic 8, alcoholic chronic 7, idiopathic acute 5). Six patients had an attack whilst on placebo but none whilst on active treatment (P = 0.032). Analysis of visual analogue scoresheets to compare background pain in the 10-week period before entry and during each phase of the trial, using a 10-cm scale for each of 11 best descriptors, endorsed the beneficial effect of active treatment (placebo v baseline, P = 0.073; active v baseline, P less than 0.001; active v placebo, P = 0.049). The same trend emerged from analysis of pain-score diaries by conventional and time series methods. Micronutrient antioxidant therapy thus offers a new approach to the treatment of recurrent (non-gallstone) pancreatitis and/or pancreatic pain.

Instrumentation for measurement of dental plaque thickness in situ

A commercial digital micrometer has been modified mechanically and electronically to allow the measurement, in situ, of the thickness of dental plaque. The device detects initial contact between a moving probe and the plaque, and measures subsequent probe displacement through to the tooth surface. Instrument accuracy is +/- 5 micron over a displacement range of 0-5 mm, with 1 micron resolution. In practice, after a short 'learning' phase, reliable clinical results can be obtained.

Surface treatment studies aimed at streamlining fissure sealant application

Three laboratory studies were carried out with the aim of improving or streamlining enamel surface treatment procedures in fissure sealing. In Study 1, the effect of reducing acid etch time from 60 s to 10 s was assessed by SEM and tensile bond strength measurements. Reduction in etch time produced a finer etch pattern, gave a reduced but still high, bond-strength, albeit with slightly poorer long-term adhesion. Study 2 showed that a conventional acid etch treatment could completely remove acquired pellicle, without prior prophylaxis. SEM studies and bond-strength measurements corroborated this view. In Study 3, compressed air and chemical drying agents were compared for drying speed and efficiency. Compressed air gave more rapid, thorough drying, and greater resultant bond strengths.

An assessment of new dental ultraviolet sources and u.v.-polymerized fissure sealants

The performance of six dental ultraviolet (u.v.) sources was assessed to establish minimum output requirements and possible u.v. hazards. Exposure criteria for u.v.-cured materials (Nuva-seal P.A., Nuva-cote P.A., Nuva-fil P.A., Lee-seal, u.v.-Dentoseal, Uviobond, Visiobond) were assessed by determining setting time-intensity characteristics, u.v. transmission and microhardness as a function of u.v. intensity and depth. A minimum intensity of 10 mW cm-2 was required for adequate curing and both Nuva-seal P.A. and Nuva-cote P.A. set well in depth with realistic exposures. Total u.v. outputs, average intensities and spatial distributions were assessed for the u.v. sources, most of which were well above minimum requirements. Ultraviolet spectra and maximum permissible exposure measurements indicated that all of the sources were safe in normal use.

The effect of salivary contamination on fissure sealant--enamel bond strength

The effect of accidental salivary contamination on the retention of fissure sealants is investigated via in vitro bond tests and scanning electron microscopy. The strength of the bond between sealant and saliva contaminated and washed enamel (168 +/- 14 kg cm-2) is not found to be significantly different from the bond strength to uncontaminated enamel (174 +/- kg cm-2). Unwashed contaminated enamel gives significantly reduced bond strength (68 +/- 11 kg cm-2).

Studies on the setting behaviour of sealants using a new acoustic method of determining set

An acoustic method has been used to compare the setting behaviours of three chemical and three u.v. activated sealants. The setting rates of the u.v. sealants were found to have similar sub-linear dependences on the applied u.v. intensity. However, considerable differences in the rates of set of these materials were noted when the same u.v. intensities were applied. Adjusting the composition of one of the sealants (Alphaseal) increased the penetration of the u.v. radiation, resulting in a ten-fold improvement in the setting rate. Suitable exposure times and the intensities of radiation necessary to satisfactorily set these u.v. sealants are recommended.

Ultra-violet absorption by two ultra-violet activated sealants

Since the ability of u.v. setting pit and fissure sealants to set in depth is dependent on the penetration of the u.v. radiation, the absorption coefficients of Nuva-seal and Alphaseal were determined at 365 nm, the wavelength of radiation used to polymerise both materials. Nuva-seal and Alphaseal had absorption coefficients of 0.165 mm-1 and 6.25 mm-1, respectively. The u.v. fluorescent dye present in Alphaseal contributed 2.5 mm-1 to its absorption coefficient and the remaining absorption was due to the 5% w/w catalyst concentration present, since the basic resin had no significant absorption. Therefore Nuva-seal may set adequately to the depths required of fissure sealants, but Alphaseal may not, unless a very high intensity u.v. source is used. A reduction in the catalyst concentration and the removal of the u.v. fluorescent dye might improve the setting characteristics of Alphaseal.