Methods for estimating complier average causal effects for cost-effectiveness analysis.

In randomized controlled trials with treatment non-compliance, instrumental variable approaches are used to estimate complier average causal effects. We extend these approaches to cost-effectiveness analyses, where methods need to recognize the correlation between cost and health outcomes. We propose a Bayesian full likelihood approach, which jointly models the effects of random assignment on treatment received and the outcomes, and a three-stage least squares method, which acknowledges the correlation between the end points and the endogeneity of the treatment received. This investigation is motivated by the REFLUX study, which exemplifies the setting where compliance differs between the randomized controlled trial and routine practice. A simulation is used to compare the methods' performance. We find that failure to model the correlation between the outcomes and treatment received correctly can result in poor confidence interval coverage and biased estimates. By contrast, Bayesian full likelihood and three-stage least squares methods provide unbiased estimates with good coverage

Double trouble: the impact of multimorbidity and deprivation on preference-weighted health related quality of life - a cross sectional analysis of the Scottish Health Survey

<b>Objective</b> To investigate the association between multimorbidity and Preference_Weighted Health Related Quality of Life (PW_HRQoL), a score that combines physical and mental functioning, and how this varies by socioeconomic deprivation and age.<p></p> <b>Design</b> The Scottish Health Survey (SHeS) is a cross-sectional representative survey of the general population which included the SF-12, a survey of HRQoL, for individuals 20 years and over.<p></p> <b>Methods</b> For 7,054 participants we generated PW_HRQoL scores by running SF-12 responses through the SF-6D algorithm. The resulting scores ranged from 0.29 (worst health) to 1 (perfect health). Using ordinary least squares, we first investigated associations between scores and increasing counts of longstanding conditions, and then repeated for multimorbidity (2+ conditions). Estimates were made for the general population and quintiles of socioeconomic deprivation. For multimorbidity, the analyses were repeated stratifying the population by age group (20--44, 45--64, 65+).<p></p> <b>Results</b> 45% of participants reported a longstanding condition and 18% reported multimorbidity. The presence of 1, 2, or 3+ longstanding conditions were associated with average reductions in PW_HRQoL scores of 0.081, 0.151 and 0.212 respectively. Reduction in scores associated with multimorbidity was 33% greater in the most deprived quintile compared to the least deprived quintile, with the biggest difference (80%) in the 20--44 age groups. There were no significant gender differences.<p></p> <b>Conclusions</b> PW_HRQoL decreases markedly with multimorbidity, and is exacerbated by higher deprivation and younger age. There is a need to prioritise interventions to improve the HRQoL for (especially younger) adults with multimorbidity in deprived areas

Periodic cometary showers: Real or imaginary?

Since the initial reports in 1980, a considerable body of chemical and physical evidence has been accumulated to indicate that a major impact event occurred on earth 65 million years ago. The effects of this event were global in extent and have been suggested as the cause of the sudden demise or mass extinction of a large percentage of life, including the dinosaurs, at the end of the geologic time period known as the Cretaceous. Recent statistical analyses of extinctions in the marine faunal record for the last 250 million years have suggested that mass extinctions may occur with a periodicity of every 26 to 30 million years. Following these results, other workers have attempted to demonstrate that these extinction events, like that at the end of the Cretaceous, are temporally correlated with large impact events. A recent scenario suggests that they are the result of periodic showers of comets produced by either the passage of the solar system through the galactic plane or by perturbations of the cometary cloud in the outer solar system by a, as yet unseen, solar companion. This hypothesized solar companion has been given the name Nemesis

An Examination of Sport Fans’ Perceptions of the Impact of the Legalization of Sport Wagering on Their Fan Experience

Over the years, professional and collegiate organizations have fought attempts to increase the legalization of sport wagering. One argument presented by those in opposition is that increased legalization would negatively alter the manner in which fans and spectators follow, consume, and react to sporting events (Tuohy, 2013). The current research was designed to examine possible changes in fandom by investigating fans’ perceptions of the impact of increasing legalized sport wagering on their fan experience, interest in sport, and sport consumption. Participants (N = 580) completed a questionnaire packet assessing demographics, economic fan motivation, fandom, and perceptions of the impact of increased access to legalized sport gambling. Data and analyses indicated that expected impacts were small and generally positive (e.g., a modest increase in interest in sport and consumption) and that these effects were greatest among groups historically active in sport gambling (e.g., persons higher in economic motivation and sport fandom)

Multiple imputation methods for bivariate outcomes in cluster randomised trials.

Missing observations are common in cluster randomised trials. The problem is exacerbated when modelling bivariate outcomes jointly, as the proportion of complete cases is often considerably smaller than the proportion having either of the outcomes fully observed. Approaches taken to handling such missing data include the following: complete case analysis, single-level multiple imputation that ignores the clustering, multiple imputation with a fixed effect for each cluster and multilevel multiple imputation. We contrasted the alternative approaches to handling missing data in a cost-effectiveness analysis that uses data from a cluster randomised trial to evaluate an exercise intervention for care home residents. We then conducted a simulation study to assess the performance of these approaches on bivariate continuous outcomes, in terms of confidence interval coverage and empirical bias in the estimated treatment effects. Missing-at-random clustered data scenarios were simulated following a full-factorial design. Across all the missing data mechanisms considered, the multiple imputation methods provided estimators with negligible bias, while complete case analysis resulted in biased treatment effect estimates in scenarios where the randomised treatment arm was associated with missingness. Confidence interval coverage was generally in excess of nominal levels (up to 99.8%) following fixed-effects multiple imputation and too low following single-level multiple imputation. Multilevel multiple imputation led to coverage levels of approximately 95% throughout. © 2016 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd

Geophysical characteristics and crustal structure of greenstone terranes: Canadian Shield

Geophysical studies in the Canadian Shield have provided some insights into the tectonic setting of greenstone belts. Greenstone belts are not rooted in deep crustal structures. Geophysical techniques consistently indicate that greenstones are restricted to the uppermost 10 km or so of crust and are underlain by geophysically normal crust. Gravity models suggest that granitic elements are similarly restricted, although magnetic modelling suggests possible downward extension to the intermediate discontinuity around approx. 18 km. Seismic evidence demonstrates that steeply-dipping structure, which can be associated with the belts in the upper crust, is not present in the lower crust. Horizontal intermediate discontinuities mapped under adjacent greenstone and granitic components are not noticeably disrupted in the boundary zone. Geophysical evidence points to the presence of discontinuities between greenhouse-granite and adjacent metasedimentary erranes. Measured stratigraphic thicknesses of greenstone belts are often twice or more the vertical thicknesses determined from gravity modelling. Explantations advanced for the discrepancy include stratigraphy repeated by thrust faulting and/or listric normal faulting, mechanisms which are consistent with certain aspects of conceptual models of greenstone development. Where repetition is not a factor the gravity evidence points to removal of the root zones of greenstone belts. For one region, this has been attributed to magmatic stopping during resurgent caldera activity

Anti-trypanosomal antibodies in sequentially collected sera of N'Dama cattle under natural trypanosomiasis risk in The Gambia

Investigates the time of appearance and the persistence of antibodies in N'Dama cattle bitten by infected tsetse flies under controlled conditions, the serology of village animals exposed to natural trypanosomiasis risk and the time of appearance and duration of anti-trypanosomal antibodies through the monthly collection of serum samples from calves following birth

The value of repeated lumbar puncture to test for xanthochromia, in patients with clinical suspicion of subarachnoid haemorrhage, with CT-negative and initial traumatic tap.

OBJECTIVES: For the diagnosis of subarachnoid haemorrhage (SAH), the presence of cerebrospinal fluid (CSF) xanthochromia is still considered the gold standard for patients with a thunderclap headache, in the absence of blood on brain CT scan. However, a traumatic lumbar puncture (LP) typically results in high concentrations of oxyhaemoglobin in CSF, impairing the detection of xanthochromia and preventing the reliable exclusion of SAH. In this context, the value of a repeat lumbar puncture has not yet been described. MATERIALS AND METHODS: A retrospective case series of suspected SAH patients, with a negative CT scan and initial traumatic LP, managed with a repeat LP to assess for CSF xanthochromia. Clinical notes, laboratory and imaging results were reviewed. RESULTS: Between August 2011 and January 2020, 31 patients with suspected SAH were referred to our neurosurgical unit following negative CT and traumatic LP. A repeat LP was performed in 7 of the 31 patients, 2.4 days (±0.79 SD) after the first traumatic LP. CSF spectrophotometry analysis from repeated LP in all 7 patients was negative for xanthochromia. No adverse clinical events were recorded on average 18 months following discharge. CONCLUSION: A repeat LP performed following a traumatic tap can still yield xanthochromia-negative CSF, thereby, excluding SAH, avoiding unnecessary invasive angiography and overall promoting the safer management of these patients