Comparison of Provision of Stroke Care in Younger and Older Patients: Findings from the South London Stroke Register

Background. Evidence-based stroke care should be available to all patients. However, evidence exists of inequalities according to age. This study compared access to care for younger adults to that for over 65s. Methods. Using population-based data from 4229 patients with first-ever stroke between 1995 and 2010, associations between age and 21 care indicators were investigated using multivariable logistic regression. Results. Age was not associated with stroke unit admission for ischaemic stroke (P = 0.666). Younger PICH patients were least likely to be admitted to stroke units (P = 0.001), instead treated on neurosurgical or ICU wards. Younger age was also associated with admission to neurosurgery or ICU after SAH (P = 0.006), increased occupational or physiotherapy at 1 year (P = 0.043), and contact with a GP 3 months after stroke (P < 0.001). Conclusion. Younger patients have equal or greater access to evidence-based care. However, there is a need to ensure that services meet the needs of this group

Socioeconomic deprivation and provision of acute and long-term care after stroke: the South London Stroke Register cohort study

Background and aims Socioeconomic deprivation (SED) is associated with increased mortality after stroke, however, its associations with stroke care remains uncertain. We assessed the SED impacts on acute and long-term stroke care, and examined their ethnic differences and secular trends. Methods We used data from 4202 patients with first-ever stroke (mean age 70.1 years, 50.4% male, 20.4% black), collected by a population-based stroke register in South London, England from 1995 to 2010. Carstairs deprivation score was measured for each patient, taking the 1st as the least deprived and the 2nd to 5th quintiles as SED, and was related to 20 indicators of care in multivariate logistic regression models. Results Patients with SED had 29% and 35% statistically significant reductions in odds of being admitted to hospital and having swallow tests, respectively. The multivariate adjusted odds ratio (OR) for receiving five indicators of acute stroke care was 0.81 (95% CI 0.72 to 0.92). It was 0.76 (0.58 to 0.99) in black patients and 0.82 (0.71 to 0.96) in white patients; and 0.70 (0.58 to 0.84) in patients with stroke occurring before 2001 and 0.89 (0.75 to 1.05) since 2001. SED was further associated with receipt of some stroke care during 5 years of follow-up, including atrial fibrillation medication (0.63, 0.48 to 0.83), and in black patients physiotherapy and occupational therapy (0.32, 0.11 to 0.92). Conclusions Stroke healthcare inequalities in England exist for some important indicators, although overall it has improved over time. The impact of SED may be stronger in black patients than in white patients. Further efforts are required to achieve stroke care equality.National Institute for Health Research Programme Grant (RP-PG-0407-10184

Provision of acute stroke care and associated factors in a multiethnic population: prospective study with the South London Stroke Register

Objectives To investigate time trends in receipt of effective acute stroke care and to determine the factors associated with provision of care

Wet and dry flexural high cycle fatigue behaviour of fully bioresorbable glass fibre composites: in-situ polymerisation versus laminate stacking

Fully bioresorbable phosphate based glass fibre reinforced polycaprolactone (PCL/PGF) composites are potentially excellent candidates to address current issues experienced with use of metal implants for hard tissue repair, such as stress shielding effects. It is therefore essential to investigate these materials under representative loading cases and to understand their fatigue behaviour (wet and dry) in order to predict their lifetime in service and their likely mechanisms of failure. This paper investigated the dry and wet flexural fatigue behaviour of PCL/PGF composites with 35% and 50% fibre volume fraction (Vf). Significantly longer flexural fatigue life (p < 0.0001) and superior fatigue damage resistance were observed for In-situ Polymerised (ISP) composites as compared to the Laminate Stacking (LS) composites in both dry and wet conditions, indicating that the ISP promoted considerably stronger interfacial bonding than the LS. Immersion in fluid (wet) during the flexural fatigue tests resulted in significant reduction (p < 0.0001) in the composites fatigue life, earlier onset of fatigue damage and faster damage propagation. Regardless of testing conditions, increasing fibre content led to shorter fatigue life for the PCL/PGF composites. Meanwhile, immersion in degradation media caused softening of both LS and ISP composites during the fatigue tests, which led to a more ductile failure mode. Among all the composites that were investigated, ISP35 (35% Vf) composites maintained at least 50% of their initial stiffness at the end of fatigue tests in both conditions, which is comparable to the flexural properties of human cortical bones. Consequently, ISP composites with 35% Vf maintained at least 50% of its flexural properties after the fatigue failure, which the mechanical retentions were well matched with the properties of human cortical bones

Impact of centralising acute stroke services in English metropolitan areas on mortality and length of hospital stay: difference-in-differences analysis

Objective: To investigate whether centralisation of acute stroke services in two metropolitan areas of England was associated with changes in mortality and length of hospital stay. Design: Analysis of difference-in-differences between regions with patient level data from the hospital episode statistics database linked to mortality data supplied by the Office for National Statistics. Setting: Acute stroke services in Greater Manchester and London, England. Participants: 258 915 patients with stroke living in urban areas and admitted to hospital in January 2008 to March 2012. Interventions “Hub and spoke” model for acute stroke care. In London hyperacute care was provided to all patients with stroke. In Greater Manchester hyperacute care was provided to patients presenting within four hours of developing symptoms of stroke. Main outcome measures Mortality from any cause and at any place at 3, 30, and 90 days after hospital admission; length of hospital stay. Results: In London there was a significant decline in risk adjusted mortality at 3, 30, and 90 days after admission. At 90 days the absolute reduction was −1.1% (95% confidence interval −2.1 to −0.1; relative reduction 5%), indicating 168 fewer deaths (95% confidence interval 19 to 316) during the 21 month period after reconfiguration in London. In both areas there was a significant decline in risk adjusted length of hospital stay: −2.0 days in Greater Manchester (95% confidence interval −2.8 to −1.2; 9%) and −1.4 days in London (−2.3 to −0.5; 7%). Reductions in mortality and length of hospital stay were largely seen among patients with ischaemic stroke. Conclusions: A centralised model of acute stroke care, in which hyperacute care is provided to all patients with stroke across an entire metropolitan area, can reduce mortality and length of hospital stay

Halo mass - concentration relation from weak lensing

We perform a statistical weak lensing analysis of dark matter profiles around tracers of halo mass from galactic- to cluster-size halos. In this analysis we use 170,640 isolated ~L* galaxies split into ellipticals and spirals, 38,236 groups traced by isolated spectroscopic Luminous Red Galaxies (LRGs) and 13,823 MaxBCG clusters from the Sloan Digital Sky Survey (SDSS) covering a wide range of richness. Together these three samples allow a determination of the density profiles of dark matter halos over three orders of magnitude in mass, from 10^{12} M_{sun} to 10^{15} M_{sun}. The resulting lensing signal is consistent with an NFW or Einasto profile on scales outside the central region. We find that the NFW concentration parameter c_{200b} decreases with halo mass, from around 10 for galactic halos to 4 for cluster halos. Assuming its dependence on halo mass in the form of c_{200b} = c_0 [M/(10^{14}M_{sun}/h)]^{\beta}, we find c_0=4.6 +/- 0.7 (at z=0.22) and \beta=0.13 +/- 0.07, with very similar results for the Einasto profile. The slope (\beta) is in agreement with theoretical predictions, while the amplitude is about two standard deviations below the predictions for this mass and redshift, but we note that the published values in the literature differ at a level of 10-20% and that for a proper comparison our analysis should be repeated in simulations. We discuss the implications of our results for the baryonic effects on the shear power spectrum: since these are expected to increase the halo concentration, the fact that we see no evidence of high concentrations on scales above 20% of the virial radius suggests that baryonic effects are limited to small scales, and are not a significant source of uncertainty for the current weak lensing measurements of the dark matter power spectrum. [ABRIDGED]Comment: 17 pages, 5 figures, accepted to JCAP pending minor revisions that are included in v2 here on arXi

In-situ polymerisation of fully bioresorbable polycaprolactone/phosphate glass fibre composites: in vitro degradation and mechanical properties

Fully bioresorbable composites have been investigated in order to replace metal implant plates used for hard tissue repair. Retention of the composite mechanical properties within a physiological environment has been shown to be significantly affected due to loss of the integrity of the fibre/matrix interface. This study investigated phosphate based glass fibre (PGF) reinforced polycaprolactone (PCL) composites with 20%, 35% and 50% fibre volume fractions (Vf) manufactured via an in-situ polymerisation (ISP) process and a conventional laminate stacking (LS) followed by compression moulding. Reinforcing efficiency between the LS and ISP manufacturing process was compared, and the ISP composites revealed significant improvements in mechanical properties when compared to LS composites. The degradation profiles and mechanical properties were monitored in phosphate buffered saline (PBS) at 37°C for 28 days. ISP composites revealed significantly less media uptake and mass loss (p<0.001) throughout the degradation period. The initial flexural properties of ISP composites were substantially higher (p<0.0001) than those of the LS composites, which showed that the ISP manufacturing process provided a significantly enhanced reinforcement effect than the LS process. During the degradation study, statistically higher flexural property retention profiles were also seen for the ISP composites compared to LS composites. SEM micrographs of fracture surfaces for the LS composites revealed dry fibre bundles and poor fibre dispersion with polymer rich zones, which indicated poor interfacial bonding, distribution and adhesion. In contrast, evenly distributed fibres without dry fibre bundles or polymer rich zones, were clearly observed for the ISP composite samples, which showed that a superior fibre/matrix interface was achieved with highly improved adhesion