The Adelaide Facial Bone Rule: A simple prediction model and clinical guideline for the presence of facial fractures using CT brain scans in victims of minor trauma

BACKGROUND

Facial fractures bleed, resulting in high-density fluid in the sinuses (haemosinus) on computed tomography (CT) scans. A CT brain scan includes most maxillary sinuses in the scan field, which should allow detection of haemosinus as an indirect indicator of a facial fracture without the need for an additional CT facial bone scan, yet no robust evidence for this exists in the literature. The aim of this study was to determine whether the presence of haemosinus on a CT brain scan, alone or in combination with other clinical information, can predict the presence of facial fractures.

METHODS

1231 adult patients, who had both brain and facial CT scans performed on the same day, were selected from a seven year period. Patients were eligible if scans were requested for trauma. Brain and facial scans were reviewed separately for the presence of facial fractures, haemosinus, emphysema and intra-cranial haemorrhage. Prediction modelling was used to assess whether findings from brain scans could be used to identify patients requiring further CT scanning.

FINDINGS

The full prediction model included four predictors and showed excellent discrimination (AUROC 0.982; 95 % CI 0.971 - 0.993). A simplified model, more suitable for clinical implementation, used only facial fractures and haemosinus as predictors. This model showed only marginally poorer discrimination (AUROC 0.964; 95 % CI 0.945 - 0.983) and excellent performance on other measures.

CONCLUSION

Based on the excellent performance of the simplified prediction model, we present the Adelaide Facial Bone Rule: The absence of blood in the sinuses or facial fractures on a CT brain scan means a CT facial bone scan does not need to be routinely performed in the setting of clinically-determined minor trauma.

Obstetric and medical factors rather than psychosocial characteristics explain why eligible women do not complete the enhanced recovery after elective caesarean (EREC) pathway: A prospective cohort study

BACKGROUND

An Australian health-service implemented an 'enhanced recovery after elective caesarean' pathway with next-day discharge.

PROBLEM

Previous anecdotal reports indicated that a large percentage of eligible women were not discharged the next day and therefore were not regarded as having completed the pathway. Psychosocial factors were expected to be the leading reason for prolonged hospitalisation.

AIM

The study objectives were to: enumerate the percentage of women assessed as eligible for EREC who subsequently did not complete the pathway and the reasons; and to describe women's antenatal satisfaction with preparation, preferences, and perceived support. Women who completed the pathway versus those who did not were compared on antenatal biopsychosocial characteristics.

METHODS

This exploratory prospective cohort study enrolled consenting eligible women from antenatal clinics and used patient records and questionnaire data. Comparative statistical techniques were used.

FINDINGS

62 % of women did not complete the pathway, with medical and obstetric factors being the most common reasons (80 %). There was statistically significant evidence of lower antenatal stress levels for those who completed EREC (median=5) relative to those who did not (median=8; P = 0.035); although these findings may not be of clinical importance. Antenatally, 51 % of women felt prepared for early discharge, 36 % needed more information, 19 % disliked hospital, 93 % agreed that family togetherness after birth was important. Most agreed that staff (76 %) and family (67 %) supported the pathway.

CONCLUSION

This study indicated that a large percentage of women assessed as eligible did not complete EREC and that obstetric and medical factors, rather than psychosocial characteristics, largely explained this. This provides reassurance to clinicians and women that discharge home is working as intended and is useful for planning similar models of care. Higher stress levels in the antenatal period were demonstrated for women who did not complete EREC suggesting the need for further research into how to support these women.

Psychosocial outcomes from one cohort participating in the STan Australian Randomised controlled Trial (START)

BACKGROUND

In an Australian randomized controlled trial (RCT), two techniques for intrapartum fetal surveillance were compared: ST analysis (STan) as an adjunct to cardiotocography (CTG), compared with CTG alone. The aim was to determine whether CTG + STan could reduce emergency cesarean birth rates while maintaining or improving neonatal outcomes. Secondary aims were to compare clinical, economic, and psychosocial outcomes. The purpose of this paper was to present psychosocial outcomes from one cohort enrolled in the trial.

METHODS

The study was conducted at one tertiary referral hospital. Participants who had taken part in the trial from the outset were invited to complete a questionnaire between March 2018 and January 2020, approximately 8 weeks after giving birth. Outcomes included depression, psychological distress, health-related quality of life, and infant feeding practices. Analysis was by intention to treat.

RESULTS

N = 207/527 participants completed the questionnaire (n = 113, STan; n = 94, CTG alone). Overall, no statistically significant or clinically meaningful differences were found in the two groups for symptoms of depression, psychological distress, quality of life, or infant feeding. A statistically significant difference was observed for the subscale of pain-discomfort, where scores were higher on average in the CTG alone arm relative to that in the CTG + STan arm.

CONCLUSIONS

Although STan as an adjunct to CTG constitutes a different clinical technology from CTG alone, both monitoring types appeared to produce similar results in terms of postnatal psychosocial outcomes for women. Findings from this study provide service users and staff with a comprehensive assessment of STan that can be used to make evidence-informed decisions about monitoring options should STan become more widely available.

The weighted cumulative exposure method and its application to pharmacoepidemiology: A narrative review

PURPOSE

The weighted cumulative exposure (WCE) method has been used in a number of fields including pharmacoepidemiology where it can account for intensity, duration and timing of exposures on the risk of an outcome. The method uses a data driven approach with flexible cubic B-splines to assign weights to past doses and select an aetiologically appropriate time window. Predictions of risk are possible for common exposure patterns encountered in real-world studies. The purpose of this study was to describe applications of the WCE method to pharmacoepidemiology and assess the strengths and limitations of the method.

METHOD

A literature search was undertaken to find studies applying the WCE method to the study of medicines. Articles published in PubMed using the search term 'weighted cumulative exposure' and articles citing Sylvestre et al. (2009) in Google Scholar or Scopus up to March 2023 were subsequently reviewed. Articles were selected based on title and review of abstracts.

RESULTS

Seventeen clinical applications using the data-driven WCE method with flexible cubic splines were identified in the review. These included 3 case-control studies and 14 cohort studies, of which 12 were analysed with Cox proportional hazards models and 2 with logistic regression. Thirteen studies used time windows of 1 year or longer. Of 11 studies which compared conventional models with the WCE method, 10 (91%) studies found a better fit with WCE models while one had an equivalent fit. The freely available 'WCE' software package has facilitated the applications of the WCE method with flexible cubic splines.

CONCLUSIONS

The WCE method allows additional insights into the effect of cumulative exposure on outcomes, including the timing and intensity (dose) of the exposure on the risk. The flexibility of the method is particularly well suited to studies with long-term exposures that vary over time or where the current risk of an event is affected by how far the exposure is in the past, which is difficult to model with conventional definitions of exposure. Interpretation of the results can be more complex than for conventional models and would be facilitated by a standardised reporting framework.

Comparison of effect of CTG + STan with CTG alone on emergency Cesarean section rate: STan Australian Randomized controlled Trial (START)

OBJECTIVE

To investigate whether use of ST analysis of the fetal electrocardiogram (STan) as an adjunct to continuous cardiotocography (CTG) reduces the rate of emergency Cesarean section (EmCS) compared with CTG alone.

METHODS

This was a randomized controlled trial of patients with a singleton fetus in cephalic presentation at ≥ 36 weeks' gestation, requiring continuous electronic fetal monitoring during labor at a tertiary maternity hospital in Adelaide, Australia, between January 2018 and July 2021. Participants were randomized to undergo CTG + STan or CTG alone. The calculated sample size was 1818 participants. The primary outcome was EmCS. Secondary outcomes included metabolic acidosis, a composite adverse perinatal outcome, and other maternal and neonatal morbidity and safety outcomes.

RESULTS

The present study enrolled 970 women, of whom 967 were included in the primary analysis. EmCS occurred in 107/482 (22.2%) deliveries in the CTG + STan arm and in 107/485 (22.1%) in the CTG arm (adjusted relative risk, 1.02 (95% CI, 0.81-1.27); P = 0.89). There was no difference in the rate of adverse maternal or neonatal outcomes between arms.

CONCLUSIONS

The addition of STan as an adjunct to continuous CTG did not reduce the EmCS rate. The smaller-than-anticipated sample size meant that this study was underpowered to detect absolute differences of ≤ 5% and, therefore, this negative finding could be due to a Type-2 error. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Profiling cognitive-motor interference in a large sample of persons with progressive multiple sclerosis and impaired processing speed: results from the CogEx study

BACKGROUND

Performing cognitive-motor dual tasks (DTs) may result in reduced walking speed and cognitive performance. The effect in persons with progressive multiple sclerosis (pwPMS) having cognitive dysfunction is unknown.

OBJECTIVE

To profile DT-performance during walking in cognitively impaired pwPMS and examine DT-performance by disability level.

METHODS

Secondary analyses were conducted on baseline data from the CogEx-study. Participants, enrolled with Symbol Digit Modalities Test 1.282 standard deviations below normative value, performed a cognitive single task ([ST], alternating alphabet), motor ST (walking) and DT (both). Outcomes were number of correct answers on the alternating alphabet task, walking speed, and DT-cost (DTC: decline in performance relative to the ST). Outcomes were compared between EDSS subgroups (≤ 4, 4.5-5.5, ≥ 6). Spearman correlations were conducted between the DTCmotor with clinical measures. Adjusted significance level was 0.01.

RESULTS

Overall, participants (n = 307) walked slower and had fewer correct answers on the DT versus ST (both p < 0.001), with a DTCmotor of 15.8% and DTCcognitive of 2.7%. All three subgroups walked slower during the DT versus ST, with DTCmotor different from zero (p's < 0.001). Only the EDSS ≥ 6 group had fewer correct answers on the DT versus ST (p < 0.001), but the DTCcognitive did not differ from zero for any of the groups (p ≥ 0.039).

CONCLUSION

Dual tasking substantially affects walking performance in cognitively impaired pwPMS, to a similar degree for EDSS subgroups.

Cardiovascular disease, associated risk factors, and risk of dementia: An umbrella review of meta-analyses

Introduction

Cardiovascular diseases (CVDs) have been associated with an increased risk of dementia; yet the evidence is mixed. This review critically appraises and synthesises current evidence exploring associations between dementia risk and CVD and their risk factors, including coronary heart disease, heart failure, atrial fibrillation, hypertension, hyperlipidaemia, and arterial stiffness.

Methods

MEDLINE, Embase, PsycINFO, and the Cochrane Database of Systematic Reviews were searched to identify systematic reviews with meta-analyses investigating the association between at least one of the CVDs of interest and dementia risk. The Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Systematic Reviews was used to assess methodological quality.

Results

Twenty-five meta-analyses published between 2007 and 2021 were included. Studies largely consisted of cohorts from North America and Europe. Findings were variable, with coronary heart disease, heart failure, and atrial fibrillation consistently associated with increased risk for all-cause dementia, but results were inconsistent for Alzheimer's disease. Hypertension was more frequently associated with dementia during mid-life compared to late life. Findings concerning cholesterol were complex, and while results were inconsistent for low-density lipoprotein cholesterol and total cholesterol, there appeared to be no associations between triglycerides and high-density lipoprotein cholesterol. All meta-analyses investigating hypercholesterolaemia showed significant increases in dementia risk. There was a paucity of research on the association between arterial stiffness and dementia risk.

Conclusion

Targeted CVD dementia prevention strategies could reduce dementia prevalence. Future research should determine the underpinning mechanisms linking heart and brain health to determine the most effective strategies for dementia risk reduction in CVD populations.

Extrapolation of Survival Curves Using Standard Parametric Models and Flexible Parametric Spline Models: Comparisons in Large Registry Cohorts with Advanced Cancer

BACKGROUND

It is often important to extrapolate survival estimates beyond the limited follow-up times of clinical trials. Extrapolated survival estimates can be highly sensitive to model choice; thus, appropriate model selection is crucial. Flexible parametric spline models have been suggested as an alternative to standard parametric models; however, their ability to extrapolate is not well understood.

AIM

To determine how well standard parametric and flexible parametric spline models predict survival when fitted to registry cohorts with artificially right-censored follow-up times.

METHODS

Adults with advanced breast, colorectal, small cell lung, non-small cell lung, or pancreatic cancer with a potential follow-up time of 10 y were selected from the SEER 1973-2015 registry data set. Patients were classified into 15 cohorts by cancer and age group at diagnosis (18-59, 60-69, 70+ y). Follow-up times for each cohort were right censored at 20%, 35%, and 50% survival. Standard parametric models (exponential, Weibull, Gompertz, log-logistic, log-normal, generalized gamma) and spline models (proportional hazards, proportional odds, normal/probit) were fitted to the 10-y data set and the 3 right-censored data sets. Predicted 10-y restricted mean survival time and percentage surviving at 10 y were compared with the observed values.

RESULTS

Across all data sets, the spline odds and spline normal models most frequently gave accurate predictions of 10-y survival outcomes. Visually, spline models tended to demonstrate better fit to the observed hazard functions than standard parametric models, both in the censored and 10-y data.

CONCLUSIONS

In these cohorts, where there was little uncertainty in the observed data, the spline models performed well when extrapolating beyond the observed data. Spline models should be routinely included in the set of models that are fitted when extrapolating cancer survival data.

Reduced length of hospital stay after caesarean section: A systematic review examining women's experiences and psychosocial outcomes

BACKGROUND

Globally, reducing hospital stays after caesarean section is becoming more prevalent. Whilst this reduction in length of stay after caesarean section has not been found to be associated with adverse maternal health outcomes, the psychosocial impact and women's experiences have not been systematically reviewed. This review aims to evaluate the literature on women's experiences and psychosocial outcomes (including infant feeding) associated with a reduced hospital stay after caesarean section.

METHODS

A mixed methods systematic review examining records between 1980 and 2019 was undertaken. The review included research which defines a reduced length of stay in comparison with standard care or a comparator with a longer discharge time. It considered data related to the antenatal period, time of discharge and postnatal period. The following databases were searched: PsycINFO, CINAHL, PubMed, Embase and ProQuest Dissertations and Theses. 13,760 records were identified, after duplicates were removed, 10,902 articles were reviewed for suitability by title and abstract. 78 full text articles were assessed, and the final review included 8 articles.

RESULTS

A total of 8 articles were included, and four areas were examined: satisfaction with care, mental wellbeing, infant feeding and pain. Articles were of mixed quality when assessed using the Mixed Methods Appraisal Tool.

CONCLUSIONS

This review indicated no evidence of a systematic negative impact on women's psychosocial outcomes and experiences. The review also identifies a number of characteristics of care associated with more positive experiences and psychosocial outcomes. These include the provision of support systems, access to pain management before and after discharge and continued care with home midwifery. The limited number of studies point to the need for more research, and especially those using qualitative methods.

Re-designing a rapid response system: effect on staff experiences and perceptions of rapid response team calls

Background

Rapid Response Team (RRT) calls are clinical crises. Clinical and time pressures can hinder effective liaison between staff who call the RRT (‘users’) and those responding as part of the RRT (‘members’). Non-technical skills (NTS) training has been shown to improve communication and cooperation but requires time and financial resources that may not be available in acute care hospitals. Rapid Response System (RRS) re-design, aiming to promote use of NTS, may provide an alternative approach to improving interactions within RRTs and between members and users.

Methods

Re-design of an existing mature RRS was undertaken in a tertiary, metropolitan hospital incorporating the addition of: 1) regular RRT meetings 2) RRT role badges and 3) a structured member-to-user patient care responsibility “hand-off” process. To compare experiences and perceptions of calls, users and members were surveyed pre and post re-design.

Results

Post re-design there were improvements in members’ understanding of RRT roles (P = 0.03) and responsibilities (P < 0.01), and recollection of introducing themselves to users (P = 0.02). For users, after the re-design, there were improvements in identification of the RRT leader (P < 0.01), and in the development of clinical plans for patients remaining on the ward at the end of an RRT call (P < 0.01). However, post-re-design, fewer users agreed that the structured hand-off was useful or that they should be involved in the process. Both members and users reported fewer experiences of conflict at RRT calls post-re-design (both P < 0.01).

Conclusion

The RRS re-design yielded improvements in interactions between members in RRTs and between RRT members and users. However, some unintended consequences arose, particularly around user satisfaction with the structured hand-off. These findings suggest that refinement and improvement of the RRS is possible, but should be an ongoing iterative effort, ideally supported by staff training.

Trial registration

NCT01551160. Registered: 12th March 2012.

Data harmonization for collaborative research among MS registries: A case study in employment

OBJECTIVE

To assess the feasibility of collaboration and retrospective data harmonization among three multiple sclerosis (MS) registries by investigating employment status.

METHODS

We used the Maelstrom guidelines to facilitate retrospective harmonization of data from three MS registries, including the NARCOMS (North American Research Committee on MS) Registry, German MS Register (GMSR), and United Kingdom MS (UK-MS) Register. A protocol was developed based on the guidelines, and summary-level data were used to combine results. Employment status and a limited set of factors associated with employment (age, sex, education, and disability level) were harmonized. A meta-analytic approach was used to pool estimates using a weighted average of logistic regression estimates and their variances in a random effects model.

RESULTS

Employment status, age, sex, education, and disability were mapped. The overall employment rate was 57% (11,143 employed out of 19,562 persons with MS) with the GMSR having the highest proportion of participants employed (66.2%), followed by the UK-MS (55.2%) and NARCOMS (43.0%) registries. As disability level increased, the odds of not being employed increased.

CONCLUSION

Harmonization across registries was feasible. The Maelstrom guidelines provide a valuable roadmap for conducting high-quality harmonization projects. The pooling of data sources has the potential to be an important mechanism for conducting research in MS.

A qualitative study of a sample of women participating in an Australian randomised controlled trial of intrapartum fetal surveillance

BACKGROUND

The STan Australian Randomised controlled Trial (START), the first of its kind in Australia, compares two techniques of intrapartum fetal surveillance (cardiotocographic electronic fetal monitoring (CTG) plus analysis of the ST segment of the fetal electrocardiogram (STan+CTG) with CTG alone) with the aim of reducing unnecessary obstetric intervention. It is also the first comprehensive intrapartum fetal surveillance (IFS) trial worldwide, including qualitative examination of psychosocial outcomes and cost-effectiveness. In evaluating and implementing healthcare interventions, the perspectives and experiences of individuals directly receiving them is an integral part of a comprehensive assessment. Furthermore, the added value of using qualitative research alongside randomised controlled trials (RCTs) is becoming widely acknowledged.

OBJECTIVE

This study aimed to examine women's experiences with the type of IFS they received in the START trial.

METHODS

Using a qualitative research design, a sample of thirty-two women were interviewed about their experiences with the fetal monitoring they received. Data were analysed using thematic analysis.

FINDINGS

Six themes emerged from analysis: reassurance, mobility, discomfort, perception of the fetal Scalp Electrode (FSE), and overall positive experience.

CONCLUSION

Interestingly, it was found that women who had an FSE in the CTG alone arm of the trial reported very similar experiences to women in the STan+CTG arm of the trial. Despite STan and CTG differing clinically, from women's perspectives, the primary difference between the two techniques was the utilisation (or not) of the FSE. Women were very accepting of STan+CTG as it was perceived and experienced as a more accurate form of monitoring than CTG alone. Findings from this study have significant implications for health professionals including midwives and obstetricians and implications for standard practice and care. The study has demonstrated the importance and significance of incorporating qualitative enquiry within RCTs.

Women's psychosocial outcomes following an emergency caesarean section: A systematic literature review

Background

Given the sudden and unexpected nature of an emergency caesarean section (EmCS) coupled with an increased risk of psychological distress, it is particularly important to understand the psychosocial outcomes for women. The aim of this systematic literature review was to identify, collate and examine the evidence surrounding women’s psychosocial outcomes of EmCS worldwide.

Methods

The electronic databases of EMBASE, PubMed, Scopus, and PsycINFO were searched between November 2017 and March 2018. To ensure articles were reflective of original and recently published research, the search criteria included peer-reviewed research articles published within the last 20 years (1998 to 2018). All study designs were included if they incorporated an examination of women’s psychosocial outcomes after EmCS. Due to inherent heterogeneity of study data, extraction and synthesis of both qualitative and quantitative data pertaining to key psychosocial outcomes were organised into coherent themes and analysis was attempted.

Results

In total 17,189 articles were identified. Of these, 208 full text articles were assessed for eligibility. One hundred forty-nine articles were further excluded, resulting in the inclusion of 66 articles in the current systematic literature review. While meta-analyses were not possible due to the nature of the heterogeneity, key psychosocial outcomes identified that were negatively impacted by EmCS included post-traumatic stress, health-related quality of life, experiences, infant-feeding, satisfaction, and self-esteem. Post-traumatic stress was one of the most commonly examined psychosocial outcomes, with a strong consensus that EmCS contributes to both symptoms and diagnosis.

Conclusions

EmCS was found to negatively impact several psychosocial outcomes for women in particular post-traumatic stress. While investment in technologies and clinical practice to minimise the number of EmCSs is crucial, further investigations are needed to develop effective strategies to prepare and support women who experience this type of birth.

Comparing the effect of STan (cardiotocographic electronic fetal monitoring (CTG) plus analysis of the ST segment of the fetal electrocardiogram) with CTG alone on emergency caesarean section rates: study protocol for the STan Australian Randomised controlled Trial (START)

BACKGROUND

Cardiotocography is almost ubiquitous in its use in intrapartum care. Although it has been demonstrated that there is some benefit from continuous intrapartum fetal monitoring using cardiotocography, there is also an increased risk of caesarean section which is accompanied by short-term and long-term risks to the mother and child. There is considerable potential to reduce unnecessary operative delivery with up to a 60% false positive diagnosis of fetal distress using cardiotocography alone. ST analysis of the fetal electrocardiogram is a promising adjunct to cardiotocography alone, and permits detection of metabolic acidosis of the fetus, potentially reducing false positive diagnosis of fetal distress.

METHODS

This study will be a single-centre, parallel-group, randomised controlled trial, conducted over 3 years. The primary hypothesis will be that the proportion of women with an emergency caesarean section on ST analysis will not equal that for women on cardiotocography monitoring alone. Participants will be recruited at the Women's and Children's Hospital, a high-risk specialty facility with approximately 5000 deliveries per annum. A total of 1818 women will be randomised to the treatment or conventional arm with an allocation ratio of 1:1, stratified by parity. The primary outcome is emergency caesarean section (yes/no). Statistical analysis will follow standard methods for randomised trials and will be performed on an intention-to-treat basis. Secondary maternal and neonatal outcomes will also be analysed. Additional study outcomes include psychosocial outcomes, patient preferences and cost-effectiveness.

DISCUSSION

Approximately 20% of Australian babies are delivered by emergency caesarean section. This will be the first Australian trial to examine ST analysis of the fetal electrocardiogram as an adjunct to cardiotocography as a potential method for reducing this proportion. The trial will be among the first to comprehensively examine ST analysis, taking into account the impact on psychosocial well-being as well as cost-effectiveness. This research will provide Australian evidence for clinical practice and guideline development as well as for policy-makers and consumers to make informed, evidence-based choices about care in labour.

TRIAL REGISTRATION

ANZCTR, ACTRN1261800006268 . Registered on 19 January 2018.

Evaluating the Utility of a Postprocessing Algorithm for MRI Evaluation of Optic Neuritis

BACKGROUND AND PURPOSE

MR imaging is useful for the detection and/or confirmation of optic neuritis. The objective of this study was to determine whether a postprocessing algorithm selectively increases the contrast-to-noise ratio of abnormal optic nerves in optic neuritis, facilitating this diagnosis on MR imaging.

MATERIALS AND METHODS

In this retrospective case-control study, coronal FLAIR images and coronal contrast-enhanced T1WI from 44 patients (31 eyes with clinically confirmed optic neuritis and 28 control eyes) underwent processing using a proprietary postprocessing algorithm designed to detect and visually highlight regions of contiguous increases in signal intensity by increasing the signal intensities of regions that exceed a predetermined threshold. For quantitative evaluation of the effect on image processing, the contrast-to-noise ratio of equivalent ROIs and the contrast-to-noise ratio between optic nerves and normal-appearing white matter were measured on baseline and processed images. The effect of image-processing on diagnostic performance was evaluated by masked reviews of baseline and processed images by 6 readers with varying experience levels.

RESULTS

In abnormal nerves, processing resulted in an increase in the median contrast-to-noise ratio from 17.8 to 85.0 (P < .001) on FLAIR and from 19.4 to 93.7 (P < .001) on contrast-enhanced images. The contrast-to-noise ratio for control optic nerves was not affected by processing (P = 0.13). Image processing had a beneficial effect on radiologists' diagnostic performance, with an improvement in sensitivities for 5/6 readers and relatively unchanged specificities. Interobserver agreement improved following processing.

CONCLUSIONS

Processing resulted in a selective increase in the contrast-to-noise ratio for diseased nerves and corresponding improvement in the detection of optic neuritis on MR imaging by radiologists.

Image Processing to Improve Detection of Mesial Temporal Sclerosis in Adults

In this retrospective case-control study, we investigated whether an image-processing algorithm designed to exaggerate the intensity of diseased hippocampi on FLAIR images can improve the diagnostic accuracy and interobserver reliability of radiologists in detecting mesial temporal sclerosis-related hippocampal signal alteration. Herein, we share the results of this study that showed that the image processing improved the confidence of radiologists in detecting mesial temporal sclerosis-related signal alteration, allowing an improved sensitivity, specificity, and interobserver reliability.

Reasons for Repeat Rapid Response Team Calls, and Associations with In-Hospital Mortality

BACKGROUND

Previous publications noted increased mortality risk in patients subject to repeat rapid response team (RRT) calls. These patients were examined as a homogenous group, but there may be many reasons for repeat calls. Those potentially preventable by the rapid response system have not been investigated.

METHODS

In a retrospective cohort study, patients with potentially preventable repeat calls were classified into two categories: type 1 (patients who had a repeat call following an initial call that ended despite the patient still triggering RRT calling criteria [T1-PRC]) and type 2 (patients with a repeat call within 24 hours of an initial call and for the same reason [T2-PRC]). In-hospital mortality for these patients and for those with repeat calls for all other reasons (ORC) were compared to patients with only a single call during their admission (SC).

RESULTS

Mortality occurred in 31 (43.7%) T1-PRC, 13 (15.1%) T2-PRC, 56 (28.9%) ORC, and 289 (13.9%) SC patients. Univariate odds ratios (ORs), in comparison to SC patients, were 4.81 (95% confidence interval [CI]: 2.96-7.81; p < 0.001), 1.10 (95% CI: 0.60-2.02; p = 0.75), and 2.52 (95% CI: 1.80-3.52; p < 0.001), respectively. Mortality effects persisted for the T1-PRC and ORC groups after adjustment for patient, admission, and initial call characteristics with ORs of 4.07 (95% CI: 2.36-7.01; p < 0.001) and 2.29 (95% CI: 1.57-3.34; p < 0.001), respectively.

CONCLUSION

This study found that repeat calls following an initial call that ended with ongoing breach of predefined calling criteria were strongly associated with increased mortality. This highlights the risk to patients when the RRT leaves reversible clinical deterioration unresolved at the end of a call.

Assessing Therapeutic Alliance in the Context of mHealth Interventions for Mental Health Problems: Development of the Mobile Agnew Relationship Measure (mARM) Questionnaire

Background

Digital health interventions in the form of smartphone apps aim to improve mental health and enable people access to support as and when needed without having to face the stigma they may experience in accessing services. If we are to evaluate mobile health (mHealth) apps and advance scientific understanding, we also need tools to help us understand in what ways mHealth interventions are effective or not. The concept of therapeutic alliance, a measure of the quality of the relationship between a health care provider and a service user, is a key factor in explaining the effects of mental health interventions. The Agnew Relationship Measure (ARM) is a well-validated measure of therapeutic alliance in face-to-face therapy.

Objective

This study presented the first attempt to (1) explore service users’ views of the concept of relationship within mHealth mental health interventions and (2) adapt a well-validated face-to-face measure of therapeutic alliance, the Agnew Relationship Measure (ARM), for use with mHealth interventions.

Methods

In stage 1, we interviewed 9 mental health service users about the concept of therapeutic alliance in the context of a digital health intervention and derived key themes from interview transcripts using thematic analysis. In stage 2, we used rating scales and open-ended questions to elicit views from 14 service users and 10 mental health staff about the content and face validity of the scale, which replaced the word “therapist” with the word “app.” In stage 3, we used the findings from stages 1 and 2 to adapt the measure with the support of a decision-making algorithm about which items to drop, retain, or adapt.

Results

Findings suggested that service users do identify relationship concepts when thinking about mHealth interventions, including forming a bond with an app and the ability to be open with an app. However, there were key differences between relationships with health professionals and relationships with apps. For example, apps were not as tailored and responsive to each person’s unique needs. Furthermore, apps were not capable of portraying uniquely human-like qualities such as friendliness, collaboration, and agreement. We made a number of changes to the ARM that included revising 16 items; removing 4 items due to lack of suitable alternatives; and adding 1 item to capture a key theme derived from stage 1 of the study (“The app is like having a member of my care team in my pocket”).

Conclusions

This study introduces the mHealth version of the ARM, the mARM, that has good face and content validity. We encourage researchers to include this easy-to-use tool in digital health intervention studies to gather further data about its psychometric properties and advance our understanding of how therapeutic alliance influences the efficacy of mHealth interventions.

Trial Registration

International Standard Randomized Controlled Trial Number (ISRCTN) 34966555; http://www.isrctn.com/ISRCTN34966555 (Archived by WebCite at http://www.webcitation.org/6ymBVwKif)

National estimates of self-reported sitting time in adults with multiple sclerosis

BACKGROUND

Limited data exist on the prevalence and distribution of sedentary behavior (SB) in multiple sclerosis (MS).

OBJECTIVE

The objective of this paper is to describe sitting time as a metric of SB in a large national sample of people with MS.

METHODS

A total of 8004 individuals from the North American Research Committee on MS (NARCOMS) Registry completed the sitting time question from the International Physical Activity Questionnaire in spring 2015. We present descriptive data on sitting time for the total sample and across sociodemographic, clinical, and behavioral characteristics.

RESULTS

The final sample included 6483 individuals. Of these, 36.7% were classified with mild disability, 24.7% with moderate disability, and 38.6% with severe disability. Median sitting time for the total sample was 480 min/day (P25 = 310 min/day, P75 = 720 min/day). Sitting time was highest for individuals with MS who were male (540 min/day), not married (540 min/day), had a disease duration >30 years (540 min/day), were underweight (540.5 min/day), had an annual income of < $15,000 (585 min/day), presented with a progressive form of MS (600 min/day), were classified as insufficiently active (600 min/day), or presented with severe disability (661 min/day).

CONCLUSION

Sitting time is twice as high in individuals with MS compared to the general population (240 min/day).

Temporal Evolution of Disc in Young Patients with Low Back Pain and Stress Reaction in Lumbar Vertebrae

BACKGROUND AND PURPOSE

Although stress-induced bony changes often resolve with conservative treatment, the long-term effects of such mechanical stresses on intervertebral discs have not been studied. We aimed to assess the differences in the temporal evolution of disc in segments of the lumbar spine with and without signs of increased mechanical stresses.

MATERIALS AND METHODS

Using MR imaging performed >6 months apart, 2 radiologists evaluated lumbar intervertebral discs for degenerative changes affecting the annulus fibrosus, the nucleus pulposus, and the endplates in 42 patients (22 male, 20 female; mean age, 16.0 ± 3.7 years [range, 7-25 years]) with low back pain and imaging evidence of stress reaction/fracture in the lumbar spine. Data were analyzed for differences in the presence and progression of disc degeneration in stressed versus nonstressed segments.

RESULTS

At baseline, stressed discs had a higher burden of annular fissures, radial fissures, herniation, and nuclear degeneration. Endplate defect burden was comparable in stressed and control discs. At follow-up, the burden of new annular fissures and endplate defects was comparable for stressed and control discs. However, a higher proportion of stressed discs showed worsening nuclear signal intensity grade (14.3% versus 0% control discs; P = .008) and worsening nuclear degeneration grade (11.9% versus 0% control discs; P = .02). An increased risk of progressive nuclear degeneration of stressed discs was observed irrespective of the outcome of bony changes.

CONCLUSIONS

Stressed discs exhibit a higher burden of nuclear and annular degeneration at baseline. These discs have a higher risk of progressive nuclear degeneration irrespective of improvement or worsening of stress-related bony changes.

The effects of air pollution on asthma hospital admissions in Adelaide, South Australia, 2003-2013: time-series and case-crossover analyses

BACKGROUND

Air pollution can have adverse health effects on asthma sufferers, but the effects vary with geographic, environmental and population characteristics. There has been no long time-series study in Australia to quantify the effects of environmental factors including pollen on asthma hospitalizations.

OBJECTIVES

This study aimed to assess the seasonal impact of air pollutants and aeroallergens on the risk of asthma hospital admissions for adults and children in Adelaide, South Australia.

METHODS

Data on hospital admissions, meteorological conditions, air quality and pollen counts for the period 2003-2013 were sourced. Time-series analysis and case-crossover analysis were used to assess the short-term effects of air pollution on asthma hospitalizations. For the time-series analysis, generalized log-linear quasi-Poisson and negative binomial regressions were used to assess the relationships, controlling for seasonality and long-term trends using flexible spline functions. For the case-crossover analysis, conditional logistic regression was used to compute the effect estimates with time-stratified referent selection strategies.

RESULTS

A total of 36,024 asthma admissions were considered. Findings indicated that the largest effects on asthma admissions related to PM_2.5 , NO₂ , PM₁₀ and pollen were found in the cool season for children (0-17 years), with the 5-day cumulative effects of 30.2% (95% CI: 13.4-49.6%), 12.5% (95% CI: 6.6-18.7%), 8.3% (95% CI: 2.5-14.4%) and 4.2% (95% CI: 2.2-6.1%) increases in risk of asthma hospital admissions per 10 unit increments, respectively. The largest effect for ozone was found in the warm season for children with the 5-day cumulative effect of an 11.7% (95% CI: 5.8-17.9%) increase in risk of asthma hospital admissions per 10 ppb increment in ozone level.

CONCLUSION

Findings suggest that children are more vulnerable and the associations between exposure to air pollutants and asthma hospitalizations tended to be stronger in the cool season compared to the warm season, with the exception of ozone. This study has important public health implications and provides valuable evidence for the development of policies for asthma management.

The progression of end-stage osteoarthritis: analysis of data from the Australian and Norwegian joint replacement registries using a multi-state model

OBJECTIVE

The incidence of joint replacements is considered an indicator of symptomatic end-stage osteoarthritis (OA). We analysed data from two national joint replacement registries in order to investigate whether evidence of a pattern of progression of end-stage hip and knee OA could be found in data from large unselected populations.

DESIGN

We obtained data on 78,634 hip and 122,096 knee arthroplasties from the Australian Orthopaedic Association National Joint Replacement Registry and 19,786 hip and 12,082 knee arthroplasties from the Norwegian Arthroplasty Register. A multi-state model was developed where individuals were followed from their first recorded hip or knee arthroplasty for OA to receiving subsequent hip and/or knee arthroplasties. We used this model to estimate relative hazard rates and probabilities for each registry separately.

RESULTS

The hazard rates of receiving subsequent arthroplasties in non-cognate joints were higher on the contralateral side than on the ipsilateral side to the index arthroplasty, especially if the index was a hip arthroplasty. After 5 years, the estimated probabilities of having received a knee contralateral to the index hip were more than 1.7 times the probabilities of having received a knee ipsilateral to the index hip.

CONCLUSION

The results indicate that there is an association between the side of the first hip arthroplasty and side of subsequent knee arthroplasties. Further studies are needed to investigate whether increased risk of receiving an arthroplasty in the contralateral knee is related to having a hip arthroplasty and/or preoperative factors such as pain and altered gait associated with hip OA.

Choice of observational study design impacts on measurement of antipsychotic risks in the elderly: a systematic review

Background

Antipsychotics are frequently and increasingly prescribed to treat the behavioural symptoms associated with dementia despite their modest efficacy. Evidence regarding the potential adverse events of antipsychotics is limited and little is known about the longer-term safety of these medicines in the elderly. The aim of this review was to determine the impact of the choice of observational study design and methods used to control for confounding on the measurement of antipsychotic risks in elderly patients.

Methods

We searched PUBMED and the Cochrane controlled trials register for double-blind randomised controlled trials (RCTs), meta-analyses and published observational studies of antipsychotics.

Results

Forty four studies were identified for the endpoints; death, cerebrovascular events, hip fracture and pneumonia. RCTs found a 20% to 30% increased risk of death, or an absolute increase of 1extra death per 100 patients with atypical antipsychotics compared to non-use. Cohort and instrumental variable analyses estimated between 2 to 7 extra deaths per 100 patients with conventional compared to atypical antipsychotics. RCTs found a 2 to 3 times increased risk of all cerebrovascular events with atypical antipsychotics compared to placebo and no association with serious stroke that required hospitalisation. Observational studies using cohort and self-controlled case-series designs reported similar results; no association where the endpoint was stroke causing hospitalisation and a doubling of risk when minor stroke was included. No RCTs were available for the outcome of hip fracture or pneumonia. Observational studies reported a 20% to 40% increased risk of hip fracture with both antipsychotic classes compared to non-use. The risk of pneumonia was a 2 to 3 times greater with both classes compared to non-use while a self-controlled case-series study estimated a 60% increased risk. Conventional antipsychotics were associated with a 50% greater hip fracture risk than atypical antipsychotics, while the risk of pneumonia was similar between the classes.

Conclusions

Choice of observational study design is critical in studying the adverse effects of antispychotics. Cohort and instrumental variable analyses gave more consistent results to clinical studies for mortality outcomes as have self-controlled case-series for the risk of cerebrovascular events and stroke. Observational evidence has highlighted the potential for antipsychotics to be associated with serious adverse events that were not reported in RCTs including hip fracture and pneumonia. Good quality observational studies are required, that employ appropriate study designs that are robust towards unmeasured confounding, to confirm the potential excess risk of hip fracture and pneumonia with antipsychotics.

Multi-state models and arthroplasty histories after unilateral total hip arthroplasties: introducing the Summary Notation for Arthroplasty Histories

BACKGROUND AND PURPOSE

An increasing number of patients have several joint replacement procedures during their lifetime. We investigated the use and suitability of multi-state model techniques in providing a more comprehensive analysis and description of complex arthroplasty histories held in arthroplasty registries than are allowed for with traditional survival methods.

PATIENTS AND METHODS

We obtained data from the Australian Orthopaedic Association National Joint Replacement Registry on patients (n = 84,759) who had undergone a total hip arthroplasty for osteoarthritis in the period 2002-2008. We set up a multi-state model where patients were followed from their first recorded arthroplasty to several possible states: revision of first arthroplasty, either a hip or knee as second arthroplasty, revision of the second arthroplasty, and death. The Summary Notation for Arthroplasty Histories (SNAH) was developed in order to help to manage and analyze this type of data.

RESULTS

At the end of the study period, 12% of the 84,759 patients had received a second hip, 3 times as many as had received a knee. The estimated probabilities of having received a second arthroplasty decreased with age. Males had a lower transition rate for receiving a second arthroplasty, but a higher mortality rate.

INTERPRETATION

Multi-state models in combination with SNAH codes are well suited to the management and analysis of arthroplasty registry data on patients who experience multiple joint procedures over time. We found differences in the progression of joint replacement procedures after the initial total hip arthroplasty regarding type of joint, age, and sex.

Comparison of pain models to detect opioid-induced hyperalgesia

Objective

Chronic opioid therapy may be associated with hyperalgesia. Our objective was to determine if opioid-induced hyperalgesia detection sensitivity is dependent on the stimulus used to detect it.

Methods

This open design study compared the detection of hyperalgesia in opioid-dependent subjects (n = 16) and healthy control subjects (n = 16) using the following pain stimuli: cold pain, electrical stimulation, mechanical pressure, and ischemic pain. The opioid-dependent subjects were maintained on either methadone (n = 8) or buprenorphine (n = 8) for at least 3 months. None of the controls was dependent on opioids or other drugs of abuse.

Results

The opioid-dependent subjects were markedly more sensitive than controls to the cold pain test. Compared with the control group, the hazard ratio for ceasing the test due to intolerable pain was 7.7 (95% confidence interval [CI] 2.6–23.3) in the buprenorphine group and 4.5 (95% CI 1.7–15.6) in the methadone group, with similar data for the cold pain threshold. Of the remaining tests, there were differences only for the electrical pain threshold between treatment groups, with the geometric mean threshold in the buprenorphine group being 1.5 (95% CI 1.1–1.9)-fold higher (ie, less sensitive) than that of the controls; the geometric mean for the methadone group was 1.3 (95% CI 1.04–1.7)-fold higher than that of the controls. There were no significant differences between buprenorphine and methadone patients in test responses. Women were more sensitive to the cold pain (hazard ratio for tolerance, 3.1 [95% CI 1.4–7.3]) and ischemic tests (hazard ratio for tolerance, 2.7 [95% CI 1.2–6.1]). There were significant correlations between cold and ischemic tolerances (r = 0.50; P = 0.003) and between electrical and mechanical pain tolerances (r = 0.52; P = 0.002).

Conclusion

These findings indicate that cold pain is the most suitable of the methods tested to detect opioid-induced hyperalgesia. This is consistent with its sensitivity to detect opioid analgesia.

Different competing risks models applied to data from the Australian Orthopaedic Association National Joint Replacement Registry

PURPOSE

Here we describe some available statistical models and illustrate their use for analysis of arthroplasty registry data in the presence of the competing risk of death, when the influence of covariates on the revision rate may be different to the influence on the probability (that is, risk) of the occurrence of revision.

PATIENTS AND METHODS

Records of 12,525 patients aged 75-84 years who had received hemiarthroplasty for fractured neck of femur were obtained from the Australian Orthopaedic Association National Joint Replacement Registry. The covariates whose effects we investigated were: age, sex, type of prosthesis, and type of fixation (cementless or cemented). Extensions of competing risk regression models were implemented, allowing the effects of some covariates to vary with time.

RESULTS

The revision rate was significantly higher for patients with unipolar than bipolar prostheses (HR = 1.38, 95% CI: 1.01-1.89) or with monoblock than bipolar prostheses (HR = 1.45, 95% CI: 1.08-1.94). It was significantly higher for the younger age group (75-79 years) than for the older one (80-84 years) (HR = 1.28, 95% CI: 1.05-1.56) and higher for males than for females (HR = 1.37, 95% CI: 1.09-1.71). The probability of revision, after correction for the competing risk of death, was only significantly higher for unipolar prostheses than for bipolar prostheses, and higher for the younger age group. The effect of fixation type varied with time; initially, there was a higher probability of revision for cementless prostheses than for cemented prostheses, which disappeared after approximately 1.5 years.

INTERPRETATION

When accounting for the competing risk of death, the covariates type of prosthesis and sex influenced the rate of revision differently to the probability of revision. We advocate the use of appropriate analysis tools in the presence of competing risks and when covariates have time-dependent effects.

Risk of hospitalization for stroke associated with antipsychotic use in the elderly: a self-controlled case series

BACKGROUND

Antipsychotics are commonly used in the elderly despite a lack of safety data from randomized trials, particularly for the typical antipsychotics. Observational studies have investigated the association between antipsychotics and stroke but results vary, which may be due to lack of control for unmeasured confounding.

OBJECTIVE

To estimate the risk of hospitalization for stroke in elderly users of antipsychotics.

STUDY DESIGN AND SETTING

Using the Australian Government Department of Veterans' Affairs administrative claims dataset we utilized a self-controlled case series design to risk-adjust for potential unmeasured confounding. Risk periods prior to antipsychotic initiation were also included to search for evidence of confounding by indication. Unexposed patients were included to adjust for the increasing incidence of hospitalization for stroke with age.

RESULTS

There were 10 638 patients aged ≥65 years with at least one hospitalization for stroke identified during the 4-year period from 1 January 2003 to 31 December 2006. Of these, 514 patients were initiated on typical antipsychotics and 564 patients were initiated on atypical antipsychotics. Hospitalization for stroke was increased in the first week after initiation of a typical antipsychotic (incidence rate ratio [IRR] 2.3; 95% CI 1.3, 3.8). There was no evidence of an increased risk of hospitalization for stroke after initiation of atypical antipsychotics. The risk of hospitalization for stroke progressively increased in the weeks leading up to first-time antipsychotic treatment. However, while the risk of hospitalization for stroke in the week prior to initiating antipsychotic therapy was significantly increased for patients initiated on typical antipsychotics (IRR 7.2; 95% CI 5.3, 9.8), patients initiated on atypical antipsychotics had no excess risk in the same period (IRR 1.2; 95% CI 0.7, 2.3).

CONCLUSIONS

The results of this study are consistent with randomized controlled trial evidence indicating that there is no increased risk of serious cerebrovascular events requiring hospitalization in patients taking atypical antipsychotics. No randomized controlled trial evidence is available on the risk of hospitalization for stroke with use of typical antipsychotics in the elderly. This study found a small but significantly increased risk of hospitalization for stroke immediately following the initiation of typical antipsychotics. Antipsychotics are likely to be initiated after hospitalization for stroke. This practice is likely to reflect the prescribing of antipsychotics during hospital admission for post-stroke complications such as delirium; however, the long-term effects of this practice are unknown.

Emergence and phylogenetic analysis of amantadine-resistant influenza a subtype H3N2 viruses in Dublin, Ireland, over Six Seasons from 2003/2004 to 2008/2009

OBJECTIVES

To determine the prevalence of amantadine-resistant influenza A viruses and perform genetic analysis of isolates collected in Dublin during six seasons (2003/2004 to 2008/2009).

METHODS

Known mutations in the matrix 2 gene (M2) conferring amantadine resistance were screened and phylogenetic analysis of the haemagglutinin gene (HA) performed.

RESULTS

Of 1,180 samples, 67 influenza A viruses were isolated, 88% of which were subtype H3N2. Amantadine resistance was only found in subtype H3N2 and increased dramatically from 7% in 2003/2004 to 90% in 2008/2009. A maximum likelihood tree of the HA gene of influenza A H3N2 isolates differentiated them into two distinct clades, clade N and clade S, where the majority of isolates were amantadine-resistant and amantadine-sensitive, respectively. The clades were distinguished by amino acid substitutions, S193F and D225N, which probably conferred a selective advantage for the spread of such viruses. Phylogenetic analysis showed some degree of antigenic drift when compared with the vaccine strain of the corresponding season.

CONCLUSIONS

This study showed that circulation in Ireland of a distinct lineage, clade N, among H3N2 viruses favoured emergence of amantadine resistance. Furthermore, comparison of circulating Irish viruses and vaccine strains used in the northern hemisphere showed high similarity.

Competing risks survival analysis applied to data from the Australian Orthopaedic Association National Joint Replacement Registry

BACKGROUND AND PURPOSE

The Kaplan-Meier (KM) method is often used in the analysis of arthroplasty registry data to estimate the probability of revision after a primary procedure. In the presence of a competing risk such as death, KM is known to overestimate the probability of revision. We investigated the degree to which the risk of revision is overestimated in registry data.

PATIENTS AND METHODS

We compared KM estimates of risk of revision with the cumulative incidence function (CIF), which takes account of death as a competing risk. We considered revision by (1) prosthesis type in subjects aged 75–84 years with fractured neck of femur (FNOF), (2) cement use in monoblock prostheses for FNOF, and (3) age group in patients undergoing total hip arthroplasty (THA) for osteoarthritis (OA).

RESULTS

In 5,802 subjects aged 75–84 years with a monoblock prosthesis for FNOF, the estimated risk of revision at 5 years was 6.3% by KM and 4.3% by CIF, a relative difference (RD) of 46%. In 9,821 subjects of all ages receiving an Austin Moore (non-cemented) prosthesis for FNOF, the RD at 5 years was 52% and for 3,116 subjects with a Thompson (cemented) prosthesis, the RD was 79%. In 44,365 subjects with a THA for OA who were less than 70 years old, the RD was just 1.4%; for 47,430 subjects > 70 years of age, the RD was 4.6% at 5 years.

INTERPRETATION

The Kaplan-Meier method substantially overestimated the risk of revision compared to estimates using competing risk methods when the risk of death was high. The bias increased with time as the incidence of the competing risk of death increased. Registries should adopt methods of analysis appropriate to the nature of their data.

Exhaled nitric oxide levels and lung function changes of underground coal miners in Newcastle, Australia

The possibility of exhaled nitric oxide (eNO) in combination with lung function as a marker of airway inflammation produced by coal mining exposure was determined presuming that workers exposed to airborne hazards would possess different concentrations of eNO and decreased lung function indices, relative to control subjects recruited from the same area. The effect of smoking was also considered. A study (exposed) group comprising 186 male subjects (aged 19-58 yr) was recruited from Newcastle coal mining companies with 86 male subjects (aged 20-64 yr) from the same area, but working outside of the coal mining location, serving as controls. The parameters examined were eNO, lung function, and variables derived from an interview-administered questionnaire survey. After adjustment for age, body weight, and smoking status, no significant differences between exposed coal mining workers and controls were found for various lung function parameters. However, the exposed group was shown to have significantly lower concentrations of eNO. In the exposed group, forced expiratory volume in 1 s (FEV(1)), forced vital capacity (FVC), and FEV(1) (%) predicted were found to be significantly different between nonsmokers and smokers. The concentrations of eNO were not significantly different between smoking and nonsmokers within the exposed group. The consideration of nonsmokers alone showed that eNO was significantly lower in the exposed group compared to the control group. The consideration of smokers alone found that eNO was significantly lower in exposed subjects. In the exposed group, no significant association was detected between eNO levels and underground work duration but a significant negative association was shown between eNO and age. Data suggest that exposure to airborne hazards in coal mining is not significantly associated with lung function changes but is correlated with decreased eNO concentrations in exposed workers. While underground work duration was not found to be significantly associated with eNO concentrations in coal mining workers in this study, the potential for using eNO as a monitoring marker still exists and further studies are needed to establish its importance.

Establishing an energy balance for crop-based digestion

The paper examines methods for calculating energy surpluses through anaerobic digestion and gives some examples of the practical application of these in crop-based systems. The surplus energy is the balance between that produced as a usable energy source and that used in crop production, conversion of the biomass into biogas, and conversion of biogas into a usable form: these are the direct energy inputs. The energy balance also takes into account the embedded energy used in the construction of machinery and buildings and for their repair and maintenance: the indirect energy inputs. The area of land available for fuel production is finite and therefore the energy yield is best considered on a per hectare basis. This allows comparison of energy conversion efficiency where the biomass yield for that area may vary depending on a range of inputs, e.g. rate of fertiliser application or irrigation requirements. It also allows direct comparison between different crop species or varieties within a single species. For an accurate energy balance analysis direct and indirect energy requirements have to be established for all the stages in the crop-based energy production cycle.

Addressing the efficacy of dihydrocodeine versus methadone as an alternative maintenance treatment for opiate dependence: A randomized controlled trial

AIM

The aim of this study is to define the efficacy of dihydrocodeine as an alternative to methadone in the maintenance treatment of opiate dependence.

DESIGN

A pragmatic open-label randomized controlled study of patients recommended for opiate maintenance treatment to test equivalence of the two treatment options with follow-up continuing for up to 42 months after recruitment.

SETTING

Assessment at either Edinburgh's Community Drug Problem Service or at two general practitioner practices with specialist drug community psychiatric nurses, then with shared care follow-up.

PARTICIPANTS

Two hundred and thirty-five subjects (168 male, 67 female) with opiate dependence syndrome were recruited. Subjects selected were suitable for opiate maintenance treatment. Routine treatment was offered throughout.

INTERVENTION

Patients were randomized to receive either methadone mixture 1 mg/ml or dihydrocodeine, 30 mg or 60 mg tablets.

MEASUREMENTS

The primary outcome measure was retention in treatment. Eight secondary outcomes included total illicit opiate use, reported crime, physical health, mental health, injecting drug use, overdoses, selling drugs and being in education or work. Measures were compared over 42 months follow-up.

FINDINGS

There was no difference in groups for retention in treatment at follow-up and there was improvement in all secondary outcomes from baseline. No significant difference in outcomes was found between randomized groups over time. Compliance with randomized treatment differed by randomized group and was affected by experiences in custody during follow-up. Those randomized to dihydrocodeine were more likely to switch treatments.

CONCLUSIONS

These results, combined with existing clinical experience, provide evidence that dihydrocodeine is a viable alternative to methadone as a maintenance treatment for opiate dependence. Indirect comparisons with other studies show dihydrocodeine (and methadone) to be superior to placebo.

Analysing sequential events in clinical trials

BACKGROUND

Data from clinical trials where the endpoint is a single survival time are readily analysed by standard methods, most commonly using a semi-parametric proportional hazards approach. However, when the outcome involves two sequential survival times, standard methods may not be applicable.

METHODS

We consider methods appropriate for the analysis of survival data in clinical trials where there are two distinct, sequential and opposing survival endpoints and where inferences about the second event are of particular interest. Two motivating examples of randomized clinical trials with different designs provide important illustrations of the methodology in practice.

RESULTS

Bivariate log-normal survival models are proposed as useful way of modeling such data. These models can be simply implemented in two stages, each of which is a univariate log-normal survival analysis. Different approaches to the analyses are described according to whether a second randomized treatment assignment is made at the time when the first event occurs and the second phase of the study commences. In the absence of a second randomization, the bivariate log-normal model adjusts for selection into the second phase of the study.

CONCLUSIONS

The investigation of 'treatment sequences' should, wherever possible, be handled by repeat randomization, which can then be followed by valid, unbiased analyses. However, in many clinical trial scenarios, this is simply not possible. In this case, the best approach is to consider the data as arising from an observational study, whilst controlling for all appropriate covariates.

LIMITATIONS

The approach we describe is appropriate for log-normally distributed data but could be generalised to handle other distributions, although the process of model fitting would be less straight-forward.

Within- and between- subject variability in methadone pharmacokinetics and pharmacodynamics in methadone maintenance subjects

AIMS

To investigate within- and between-subject variability of the pharmacodynamics and pharmacokinetics of (R)- and (S)-methadone in methadone maintenance subjects at steady-state.

METHODS

Six non-holder subjects were studied on three occasions at 7-16 day intervals; doses (20-170 mg/day) remained unchanged. Blood samples and pharmacodynamic data were collected 10-12 times over a 24-h inter-dosing interval. All pharmacodynamic data were expressed as the area under the end-point versus time curve. Using analyses of variance with mixed effects, best estimates were made of the ratio of between- to within-subject variation, with corresponding 95% confidence intervals (CI) for within-subject variation at the average value.

RESULTS

Subjects were relatively consistent between occasions, whereas there was much greater between-subject variability (P < 0.02) for all measures. Estimates of the ratio of between- to within-subject variation ranged from 2.2-12.8 for pharmacodynamic measures, and 1.3-7.9 for pharmacokinetic parameters. For pain, total mood disturbance, withdrawal, pupil size and respiration rate, 95% CI for within-subject measures ranged < or = 2-fold, while this was greater for subjective direct opioid effects (4.2-fold). For CL/F of the active (R)-methadone, the variance ratio was 4.9 (P < 0.0003), with 95% CI for within-subject measures ranging < or = 2-fold. (S)-methadone CL/F demonstrated greater within-subject variability (3.4-fold), possibly contributing to a smaller (2.7; P < 0.0003) ratio of between- to within-subject variance.

CONCLUSIONS

Non-holder methadone maintenance treatment participants appear to respond consistently with respect to pharmacokinetics and pharmacodynamics over a 1-2 month period. Such knowledge may help prescribers to determine whether alternative dosing regimens or treatments might be more appropriate in this population.

Subjective and physiological responses among racemic-methadone maintenance patients in relation to relative (S)- vs. (R)-methadone exposure

AIMS

To investigate the possibility that (S)-methadone influences therapeutic and adverse responses to rac-methadone maintenance treatment, by examining how subjective and physiological responses among rac-methadone maintenance patients vary in relation to relative exposure to (S)- vs. (R)-methadone.

METHODS

Mood states (Profile of Mood States), opioid withdrawal (Methadone Symptoms Checklist), physiological responses (pupil diameter, heart rate, respiration rate, blood pressure), and plasma concentrations (CP) of (R)- and (S)-methadone were measured concurrently 11-12 times over a 24-h interdosing interval in 55 methadone maintenance patients. Average steady-state plasma concentrations (C(av)) and pharmacodynamic responses were calculated using area under the curve (AUC). Linear regression was used to determine whether variability in pharmacodynamic responses was accounted for by (S)-methadone C(av) controlling for (R)-methadone C(av) and rac-methadone dose. Ratios of (S)-:(R)-methadone using AUC(CP) and trough values were correlated with pharmacodynamic responses for all subjects and separately for those with daily rac-methadone doses > or = 100 mg.

RESULTS

(S)-methadone C(av) accounted for significant variability in pharmacodynamic responses beyond that accounted for by (R)-methadone C(av) and rac-methadone dose, showing positive associations (partial r) with the intensity of negative mood states such as Tension (0.28), Fatigue (0.31), Confusion (0.32), and opioid withdrawal scores (0.30); an opposite pattern of relationships was evident for (R)-methadone. The plasma (S)-:(R)-methadone AUC(CP) ratio (mean +/- SD 1.05 +/- 0.21, range 0.65-1.51) was not significantly related to pharmacodynamic responses for the subjects as a whole but showed significant positive associations (r) with the intensity of negative mood states such as Total Mood Disturbance (0.61), Tension (0.69), Fatigue (0.65), Confusion (0.64), Depression (0.49) and heart rate (0.59) for the > or = 100-mg dose range.

CONCLUSIONS

These findings agree with previous evidence that (S)-methadone is associated with a significant and potentially adverse profile of responses distinct from that of (R)-methadone. Individual variability in relative (S)- vs. (R)-methadone exposure may be associated with variability in response to rac-methadone maintenance treatment.