137 research outputs found

    Long Term Performance Of Passive House Buildings

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    Long term experience with Passive House buildings is illustrated with two early large scale projects, a school and an office building located in Germany. Those were monitored in lump energy performance (school, commissioned 2004) and great detail (office, commissioned 2002) respectively. Moreover, they give an indication of the characteristics of such buildings subject to changes in usage intensity. Both buildings generally performed as expected with the school facing occasional overheating in the summer due to inflexible shading controls. Following an extension in schooling hours the addition of a canteen was required and the ventilation system was adapted to the changed usage. Nevertheless the building’s user comfort and energy performance remain high,despite exceeding the Passive House primary energy target slightly due to increased electricity consumption. The office likewise meets the calculated efficiency in operation. The ground coupled cooling worked well despite greatly increased internal heat gains due to unexpected usage. This extra heat input did not, however, exhaust the geothermal (passive) cooling capacity for the future. Thermal comfort proved near optimal at all times, despite a very simple control regime of the one-circuit concrete core activation system for heating and cooling. In the last section air tightness design and measurement experience in the UK and particularly the question of long-term stability of the airtight building envelope is assessed. It was found that measurement results are not only repeatable in relatively short intervals such as a few months. The data available suggests stability of the airtight envelope over many years. Attention is required as regards the leakage of party walls of terraced buildings which need to be integrated in the overall airtightness concept. A high permeability of party walls in terraced buildings with a common airtight envelope presents a challenge for measuring air tightness. Long-term series of airtightness measurements exist for the Kranichstein House in Darmstadt/Germany and prove the stability of the chosen airtightness concept. Moreover, results for 17 early Passive House buildings in Germany in eight locations and various construction types revisited in 2001 (1.4 to 10 years after the initial airtightness test) suggest stability of air tightness values over time. Great advances have since been made in materials and methods available and the general understanding in the industry. This is supported by a large sample of 2934 Passive House projects of varied construction materials, locations, sizes and usages that yielded an average air tightness test result as low as n50 = 0.41 h-1

    The value of the pragmatic-explanatory continuum indicator summary wheel in an ongoing study: the bullous pemphigoid steroids and tetracyclines study

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    BACKGROUND: The Pragmatic-Explanatory Continuum Indicator Summary (PRECIS) tool is intended to be used in the design phase of trials to help investigative teams design trials in-line with their purpose. Our team applied this tool to an ongoing trial (BLISTER) to determine whether the initial suggestion among some team members that the trial could be described as largely pragmatic was the consensus. METHODS: Each of the six members of the BLISTER trial team was sent a blank PRECIS wheel to independently complete. The results obtained were averaged and plotted on a single PRECIS wheel to illustrate the degree of pragmatism of the trial. RESULTS: The trial team found that the design of the trial was closest to the pragmatic end of the pragmatic-explanatory continuum. The strongest consensus was found on the 'flexibility of the comparison intervention' and 'practitioner adherence' domains (SD = 13). The trial team appeared to disagree most on the 'eligibility criteria' (SD = 35) and 'participant compliance' (SD = 31) domains, although the large standard deviations were a result of a single outlier in the two domains. CONCLUSION: The PRECIS tool can be used to retrospectively determine the pragmatism of a trial provided enough expertise and information on the trial is available. Illustrating the design of a trial on the PRECIS wheel can help research users more easily identify studies of interest. We hope our recommendations for applying this useful tool will encourage others to consider using it when designing, conducting and reporting studies. TRIAL REGISTRATION: Current Controlled Trials http://www.controlled-trials.com/ISRCTN13704604

    The Cochrane Skin Group: a vanguard for developing and promoting evidence-based dermatology

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    Aim The Cochrane Skin Group (CSG) is part of the international Cochrane Collaboration (http://www.cochrane.org/). The CSG prepares, maintains and disseminates high quality evidence-based summaries on the prevention, diagnosis and treatment of skin diseases. We present a synopsis of the history, scope and priorities of the CSG. In addition, we report outcomes of CSG reviews and critically assess clinical value. Methods Descriptive analysis of systematic reviews published by the CSG since its inception including output, impact factor, associated methodological studies, and influence in clinical guidelines, promoting patient and public engagement and in triggering new primary research. Results The CSG started in 1997, and has published 61 reviews, 34 protocols and 31 registered titles by August 2013. The CSG scope includes 1000 skin diseases; 80% of reviews cover the top ten diagnoses and 40% of reviews provide clear guidance for clinical practice. CSG reviews had an impact factor of 6.1 in 2011 which places it alongside top dermatology journals. CSG reviews are typically broad in focus and have been shown to be of better quality than non-Cochrane reviews. They are highly cited in clinical guidelines. Several reviews have identified evidence gaps that have led to better primary research. Conclusions The CSG has emerged as a vanguard of evidence-based dermatology by growing a community interested in applying best external evidence to the care of skin patients and by identifying topics for research. CSG reviews are high impact, clinically relevant and have tangibly influenced international dermatology clinical practice guidelines and new research

    Bullous pemphigoid and comorbidities: a case-control study in Portuguese patients

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    BACKGROUND: Although rare, bullous pemphigoid (BP) is the most common autoimmune blistering disease. Recent studies have shown that patients with bullous pemphigoid are more likely to have neurological and psychiatric diseases, particularly prior to the diagnosis of bullous pemphigoid. OBJECTIVE: The aims were: (i) to evaluate the demographic and clinical features of bullous pemphigoid from a database of patients at a Portuguese university hospital and (ii) to compare the prevalence of comorbid conditions before the diagnosis of bullous pemphigoid with a control group. METHODS: Seventy-seven patients with bullous pemphigoid were enrolled in the study. They were compared with 176 age- and gender-matched controls, which also had the same inpatient to outpatient ratio, but no history of bullous or cutaneous malignant disease. Univariate and multivariate analyses were used to calculate odds ratios for specific comorbid diseases. RESULTS: At least one neurologic diagnosis was present in 55.8% of BP patients compared with 20.5% controls (p<0.001). Comparing cases to controls, stroke was seen in 35.1 vs. 6.8%, OR 8.10 (3.80-17.25); dementia in 37.7 vs. 11.9%, OR 5.25 (2.71-10.16); and Parkinson's disease in 5.2 vs. 1.1%, OR 4.91 (0.88-27.44). Using multivariate analysis, all diseases except Parkinson's retained their association with BP. Patients under systemic treatment were eight times more likely to have complications than those treated with topical steroids (p< 0.017). CONCLUSIONS: The results of this study substantiate the association between BP and neurological diseases. In addition, they highlight the potential complications associated with the treatment of BP

    Doxycycline compared to prednisolone therapy for patients with bullous pemphigoid: cost-effectiveness analysis of the BLISTER trial

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    BACKGROUND: Bullous pemphigoid (BP) is an autoimmune blistering skin disorder associated with significant morbidity and mortality. Doxycycline and prednisolone to treat bullous pemphigoid were compared within a randomised controlled trial (RCT). OBJECTIVES: To compare the cost-effectiveness of doxycycline-initiated and prednisolone-initiated treatment for patients with BP. METHODS: a multicentre, parallel-group, investigator-blinded RCT. Within-trial analysis used bivariate regression of costs and QALYs, with multiple imputation of missing data, informing a probabilistic assessment of incremental treatment cost-effectiveness from a health service perspective RESULTS: In the base case, there was no robust difference in costs or QALYs per patient at 1 year comparing doxycycline-initiated therapy with prednisolone-initiated therapy (net cost: £959, 95% CI -£24 to £1941; net QALYs: -0.024, 95% CI -0.088 to 0.041). However, findings varied by baseline blister severity. For patients with mild or moderate blistering (≤30) net costs and outcomes were similar. For patients with severe blistering (>30) net costs were higher (£2558, 95% CI -£82 to £5198) and quality of life poorer (-0.090 QALYs, 95% CI-0.222 to 0.042) for patients starting on doxycycline. The probability that doxycycline would be cost-effective for those with severe pemphigoid was 1.5% at a willingness to pay of £20,000/QALY. CONCLUSIONS: Consistent with the clinical findings of the BLISTER trial, patients with mild or moderate blistering should receive treatment guided by the safety and effectiveness of the drugs and patient preference - neither strategy is clearly a preferred use of NHS resources. However, prednisolone-initiated treatment may be more cost-effective for patients with severe blistering

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    Background: Bullous pemphigoid (BP) is an autoimmune blistering skin disorder associated with significant morbidity and mortality. Doxycycline and prednisolone to treat bullous pemphigoid were compared within a randomised controlled trial (RCT). Objectives: To compare the cost-effectiveness of doxycycline-initiated and prednisolone-initiated treatment for patients with BP. Methods: a multicentre, parallel-group, investigator-blinded RCT. Within-trial analysis used bivariate regression of costs and QALYs, with multiple imputation of missing data, informing a probabilistic assessment of incremental treatment cost-effectiveness from a health service perspective Results: In the base case, there was no robust difference in costs or QALYs per patient at 1 year comparing doxycycline-initiated therapy with prednisolone-initiated therapy (net cost: £959, 95% CI –£24 to £1941; net QALYs: –0.024, 95% CI –0.088 to 0.041). However, findings varied by baseline blister severity. For patients with mild or moderate blistering (≤30) net costs and outcomes were similar. For patients with severe blistering (>30) net costs were higher (£2558, 95% CI –£82 to £5198) and quality of life poorer (–0.090 QALYs, 95% CI–0.222 to 0.042) for patients starting on doxycycline. The probability that doxycycline would be cost-effective for those with severe pemphigoid was 1.5% at a willingness to pay of £20,000/QALY. Conclusions: Consistent with the clinical findings of the BLISTER trial, patients with mild or moderate blistering should receive treatment guided by the safety and effectiveness of the drugs and patient preference - neither strategy is clearly a preferred use of NHS resources. However, prednisolone-initiated treatment may be more cost-effective for patients with severe blistering

    Doxycycline versus prednisolone as an initial treatment strategy for bullous pemphigoid: a pragmatic non-inferiority randomised controlled trial

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    Background: Bullous pemphigoid (BP) is a blistering skin disorder with increased mortality. We tested whether a strategy of starting treatment with doxycycline conveys acceptable short-term blister control whilst conferring long-term safety advantages over starting treatment with oral corticosteroids. Methods: Pragmatic multi-centre parallel-group randomised controlled trial of adults with BP (≥3 blisters ≥2 sites and linear basement membrane IgG/C3) plus economic evaluation. Participants were randomised to doxycycline (200 mg/day) or prednisolone (0·5 mg/kg/day). Localised adjuvant potent topical corticosteroids (<30 g/week) was permitted weeks 1-3. The non-inferiority primary effectiveness outcome was the proportion of participants with ≤3 blisters at 6 weeks. We assumed that doxycycline would be 25% less effective than corticosteroids with a 37% acceptable margin of noninferiority. The primary safety outcome was the proportion with severe, life-threatening or fatal treatment-related adverse events by 52 weeks. Analysis used a regression model adjusting for baseline disease severity, age and Karnofsky score, with missing data imputed. Results: 132 patients were randomised to doxycycline and 121 to prednisolone from 54 UK and 7 German dermatology centres. Mean age was 77·7 years and 68.4% had moderate to severe baseline disease. For those starting doxycycline, 83/112 (74·1%) had ≤3 blisters at 6 weeks compared with 92/101 (91·1%) for prednisolone, a difference of 18·6% favouring prednisolone (upper limit of 90% CI, 26·1%, within the predefined 37% margin). Related severe, life-threatening and fatal events at 52 weeks were 18·5% for those starting doxycycline and 36·6% for prednisolone (mITT analysis), an adjusted difference of 19·0% (95% CI, 7·9%, 30·1%, p=0·001). Conclusions: A strategy of starting BP patients on doxycycline is non-inferior to standard treatment with oral prednisolone for short-term blister control and significantly safer long-term
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