Chronic non-invasive ventilation for chronic obstructive pulmonary disease

BACKGROUND: Chronic non-invasive ventilation (NIV) is increasingly being used to treat people with COPD who have respiratory failure, but the evidence supporting this treatment has been conflicting.OBJECTIVES: To assess the effects of chronic non-invasive ventilation at home via a facial mask in people with COPD, using a pooled analysis of IPD and meta-analysis.SEARCH METHODS: We searched the Cochrane Airways Register of Trials, MEDLINE, Embase, PsycINFO, CINAHL, AMED, proceedings of respiratory conferences, clinical trial registries and bibliographies of relevant studies. We conducted the latest search on 21 December 2020.SELECTION CRITERIA: We included randomised controlled trials (RCTs) comparing chronic NIV for at least five hours per night for three consecutive weeks or more (in addition to standard care) versus standard care alone, in people with COPD. Studies investigating people initiated on NIV in a stable phase and studies investigating NIV commenced after a severe COPD exacerbation were eligible, but we reported and analysed them separately. The primary outcomes were arterial blood gases, health-related quality of life (HRQL), exercise capacity (stable COPD) and admission-free survival (post-exacerbation COPD). Secondary outcomes for both populations were: lung function, COPD exacerbations and admissions, and all-cause mortality. For stable COPD, we also reported respiratory muscle strength, dyspnoea and sleep efficiency.DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. After inclusion of a study, we requested the IPD. We analysed continuous and time-to-event data using linear- and cox-regression mixed-effect models with a random effect on study level. We analysed dichotomous IPD using generalised estimating equations. We adjusted all models for age and sex. We assessed changes in outcomes after three and 12 months. We also conducted a meta-analysis on aggregated trial data.MAIN RESULTS: We included 14 new RCTs in this review update, in addition to the seven previously included. Seventeen studies investigated chronic NIV in stable COPD and four studies investigated chronic NIV commenced after a severe COPD exacerbation. Three studies compared NIV to sham continuous positive airway pressure (2 to 4 cmH2O). Seven studies used a nasal mask, one study used an oronasal mask and eight studies used both interfaces. Five studies did not report the interface. The majority of trials (20/21) were at high risk of performance bias due to an unblinded design. We considered 11 studies to have a low risk of selection bias and 13 to have a low risk of attrition bias. We collected and analysed the IPD from 13 stable COPD studies (n = 778, 68% of the participants included) and from three post-exacerbation studies (n = 364, 96% of the participants included). In the stable COPD group, NIV probably results in a minor benefit on the arterial partial pressure of oxygen (PaO2) after three months (adjusted mean difference (AMD) 0.27 kPa, 95% CI 0.04 to 0.49; 9 studies, 271 participants; moderate-certainty evidence), but there was little to no benefit at 12 months (AMD 0.09 kPa, 95% CI -0.23 to 0.42; 3 studies, 171 participants; low-certainty evidence). The arterial partial pressure of carbon dioxide (PaCO2) was reduced in participants allocated to NIV after three months (AMD -0.61 kPa, 95% CI -0.77 to -0.45; 11 studies, 475 participants; high-certainty evidence) and persisted up to 12 months (AMD -0.42 kPa, 95% CI -0.68 to -0.16; 4 studies, 232 participants; high-certainty evidence). Exercise capacity was measured with the 6-minute walking distance (minimal clinical important difference: 26 m). There was no clinically relevant effect of NIV on exercise capacity (3 months: AMD 15.5 m, 95% CI -0.8 to 31.7; 8 studies, 330 participants; low-certainty evidence; 12 months: AMD 26.4 m, 95% CI -7.6 to 60.5; 3 studies, 134 participants; very low-certainty evidence). HRQL was measured with the Severe Respiratory Insufficiency and the St. Georges's Respiratory Questionnaire and may be improved by NIV, but only after three months (3 months: standardised mean difference (SMD) 0.39, 95% CI 0.15 to 0.62; 5 studies, 259 participants; very low-certainty evidence; 12 months: SMD 0.15, 95% CI -0.13 to 0.43; 4 studies, 200 participants; very low-certainty evidence). Lastly, the risk for all-cause mortality is likely reduced by NIV (adjusted hazard ratio (AHR) 0.75, 95% CI 0.58 to 0.97; 3 studies, 405 participants; moderate-certainty evidence). In the post-exacerbation COPD group, there was little to no benefit on the PaO2 after three months, but there may be a slight decrease after 12 months (3 months: AMD -0.10 kPa, 95% CI -0.65 to 0.45; 3 studies, 234 participants; low-certainty evidence; 12 months: -0.27 kPa, 95% CI -0.86 to 0.32, 3 studies; 170 participants; low-certainty evidence). The PaCO2 was reduced by NIV at both three months (AMD -0.40 kPa, 95% CI -0.70 to -0.09; 3 studies, 241 participants; moderate-certainty evidence) and 12 months (AMD -0.52 kPa, 95% CI -0.87 to -0.18; 3 studies, 175 participants; high-certainty evidence). NIV may have little to no benefit on HRQL (3 months: SMD 0.25, 95% CI -0.01 to 0.51; 2 studies, 219 participants; very low-certainty evidence; 12 months: SMD 0.25, 95% -0.06 to 0.55; 2 studies, 164 participants; very low-certainty evidence). Admission-free survival seems improved with NIV (AHR 0.71, 95% CI 0.54 to 0.94; 2 studies, 317 participants; low-certainty evidence), but the risk for all-cause mortality does not seem to improve (AHR 0.97, 95% CI 0.74 to 1.28; 2 studies, 317 participants; low-certainty evidence).AUTHORS' CONCLUSIONS: Regardless of the timing of initiation, chronic NIV improves daytime hypercapnia. In addition, in stable COPD, survival seems to be improved and there might be a short term HRQL benefit. In people with persistent hypercapnia after a COPD exacerbation, chronic NIV might prolong admission-free survival without a beneficial effect on HRQL. In stable COPD, future RCTs comparing NIV to a control group receiving standard care might no longer be warranted, but research should focus on identifying participant characteristics that would define treatment success. Furthermore, the optimal timing for initiation of NIV after a severe COPD exacerbation is still unknown.</p

Methodological bias in cluster randomised trials

Background: Cluster randomised trials can be susceptible to a range of methodological problems. These problems are not commonly recognised by many researchers. In this paper we discuss the issues that can lead to bias in cluster trials. Methods: We used a sample of cluster randomised trials from a recent review and from a systematic review of hip protectors. We compared the mean age of participants between intervention groups in a sample of 'good' cluster trials with a sample of potentially biased trials. We also compared the effect sizes, in a funnel plot, between hip protector trials that used individual randomisation compared with those that used cluster randomisation. Results: There is a tendency for cluster trials, with evidence methodological biases, to also show an age imbalance between treatment groups. In a funnel plot we show that all cluster trials show a large positive effect of hip protectors whilst individually randomised trials show a range of positive and negative effects, suggesting that cluster trials may be producing a biased estimate of effect. Conclusion: Methodological biases in the design and execution of cluster randomised trials is frequent. Some of these biases associated with the use of cluster designs can be avoided through careful attention to the design of cluster trials. Firstly, if possible, individual allocation should be used. Secondly, if cluster allocation is required, then ideally participants should be identified before random allocation of the clusters. Third, if prior identification is not possible, then an independent recruiter should be used to recruit participants

Selection of Medical Diagnostic Codes for Analysis of Electronic Patient Records. Application to Stroke in a Primary Care Database

BACKGROUND: Electronic patient records from primary care databases are increasingly used in public health and health services research but methods used to identify cases with disease are not well described. This study aimed to evaluate the relevance of different codes for the identification of acute stroke in a primary care database, and to evaluate trends in the use of different codes over time.METHODS: Data were obtained from the General Practice Research Database from 1997 to 2006. All subjects had a minimum of 24 months of up-to-standard record before the first recorded stroke diagnosis. Initially, we identified stroke cases using a supplemented version of the set of codes for prevalent stroke used by the Office for National Statistics in Key health statistics from general practice 1998 (ONS codes). The ONS codes were then independently reviewed by four raters and a restricted set of 121 codes for 'acute stroke' was identified but the kappa statistic was low at 0.23.RESULTS: Initial extraction of data using the ONS codes gave 48,239 cases of stroke from 1997 to 2006. Application of the restricted set of codes reduced this to 39,424 cases. There were 2,288 cases whose index medical codes were for 'stroke annual review' and 3,112 for 'stroke monitoring'. The frequency of stroke review and monitoring codes as index codes increased from 9 per year in 1997 to 1,612 in 2004, 1,530 in 2005 and 1,424 in 2006. The one year mortality of cases with the restricted set of codes was 29.1% but for 'stroke annual review,' 4.6% and for 'stroke monitoring codes', 5.7%.CONCLUSION: In the analysis of electronic patient records, different medical codes for a single condition may have varying clinical and prognostic significance; utilisation of different medical codes may change over time; researchers with differing clinical or epidemiological experience may have differing interpretations of the relevance of particular codes. There is a need for greater transparency in the selection of sets of codes for different conditions, for the reporting of sensitivity analyses using different sets of codes, as well as sharing of code sets among researchers

Two chemically similar stellar overdensities on opposite sides of the plane of the Galaxy

Our Galaxy is thought to have undergone an active evolutionary history dominated by star formation, the accretion of cold gas, and, in particular, mergers up to 10 gigayear ago. The stellar halo reveals rich fossil evidence of these interactions in the form of stellar streams, substructures, and chemically distinct stellar components. The impact of dwarf galaxy mergers on the content and morphology of the Galactic disk is still being explored. Recent studies have identified kinematically distinct stellar substructures and moving groups, which may have extragalactic origin. However, there is mounting evidence that stellar overdensities at the outer disk/halo interface could have been caused by the interaction of a dwarf galaxy with the disk. Here we report detailed spectroscopic analysis of 14 stars drawn from two stellar overdensities, each lying about 5 kiloparsecs above and below the Galactic plane - locations suggestive of association with the stellar halo. However, we find that the chemical compositions of these stars are almost identical, both within and between these groups, and closely match the abundance patterns of the Milky Way disk stars. This study hence provides compelling evidence that these stars originate from the disk and the overdensities they are part of were created by tidal interactions of the disk with passing or merging dwarf galaxies.Comment: accepted for publication in Natur

Response to novel objects and foraging tasks by common marmoset (Callithrix Jacchus) female Pairs

Many studies have shown that environmental enrichment can significantly improve the psychological well-being of captive primates, increasing the occurrence of explorative behavior and thus reducing boredom. The response of primates to enrichment devices may be affected by many factors such as species, sex, age, personality and social context. Environmental enrichment is particularly important for social primates living in unnatural social groupings (i.e. same-sex pairs or singly housed animals), who have very few, or no, benefits from the presence of social companions in addition to all the problems related to captivity (e.g. increased inactivity). This study analyses the effects of enrichment devices (i.e. novel objects and foraging tasks) on the behavior of common marmoset (Callithrix jacchus) female pairs, a species that usually lives in family groups. It aims to determine which aspects of an enrichment device are more likely to elicit explorative behaviors, and how aggressive and stress-related behaviors are affected by its presence. Overall, the marmosets explored foraging tasks significantly longer than novel objects. The type of object, which varied in size, shape and aural responsiveness (i.e. they made a noise when the monkey touched them), did not affect the response of the monkeys, but they explored objects that were placed higher in the enclosure more than those placed lower down.Younger monkeys were more attracted to the enrichment devices than the older ones. Finally, stress-related behavior (i.e. scratching) significantly decreased when the monkeys were presented with the objects; aggressive behavior as unaffected. This study supports the importance of environmental enrichment for captive primates and shows that in marmosets its effectiveness strongly depends upon the height of the device in the enclosure and the presence of hidden food. The findings can be explained ifone considers the foraging behavior of wild common marmosets. Broader applications for the research findings are suggested in relation to enrichment

Long-term effect of sleeve gastrectomy vs Roux-en-Y gastric bypass in people living with severe obesity:a phase III multicentre randomised controlled trial (SleeveBypass)

Background: Sleeve gastrectomy is the most performed metabolic surgical procedure worldwide. However, conflicting results offer no clear evidence about its long-term clinical comparability to Roux-en-Y gastric bypass. This study aims to determine their equivalent long-term weight loss effects. Methods: This randomised open-label controlled trial was conducted from 2012 until 2017 in two Dutch bariatric hospitals with a 5-year follow-up (last follow-up July 29th, 2022). Out of 4045 patients, 628 were eligible for metabolic surgery and were randomly assigned to sleeve gastrectomy or Roux-en-Y gastric bypass (intention-to-treat). The primary endpoint was weight loss, expressed by percentage excess body mass index (BMI) loss. The predefined clinically relevant equivalence margin was −13% to 13%. Secondary endpoints included percentage total kilograms weight loss, obesity-related comorbidities, quality of life, morbidity, and mortality. This trial is registered with Dutch Trial Register NTR4741: https://onderzoekmetmensen.nl/nl/trial/25900. Findings: 628 patients were randomised between sleeve gastrectomy (n = 312) and Roux-en-Y gastric bypass (n = 316) (mean age 43 [standard deviation (SD), 11] years; mean BMI 43.5 [SD, 4.7]; 81.8% women). Excess BMI loss at 5 years was 58.8% [95% CI, 55%–63%] after sleeve gastrectomy and 67.1% [95% CI, 63%–71%] after Roux-en-Y gastric bypass (difference 8.3% [95% CI, −12.5% to −4.0%]). This was within the predefined margin (P &lt; 0.001). Total weight loss at 5 years was 22.5% [95% CI, 20.7%–24.3%] after sleeve gastrectomy and 26.0% [95% CI, 24.3%–27.8%] after Roux-en-Y gastric bypass (difference 3.5% [95% CI, −5.2% to −1.7%]). In both groups, obesity-related comorbidities significantly improved after 5 years. Dyslipidaemia improved more frequently after Roux-en-Y gastric bypass (83%, 54/65) compared to sleeve gastrectomy (62%, 44/71) (P = 0.006). De novo gastro-oesophageal reflux disease occurred more frequently after sleeve gastrectomy (16%, 46/288) vs Roux-en-Y gastric bypass (4%, 10/280) (P &lt; 0.001). Minor complications were more frequent after Roux-en-Y gastric bypass (5%, 15/316) compared to sleeve gastrectomy (2%, 5/312). No statistically significant differences in major complications and health-related quality of life were encountered. Interpretation: In people living with obesity grades 2 and 3, sleeve gastrectomy and Roux-en-Y gastric bypass had clinically comparable excess BMI loss according to the predefined definition for equivalence. However, Roux-en-Y gastric bypass showed significantly higher total weight loss and significant advantages in secondary outcomes, including dyslipidaemia and GERD, yet at a higher rate of minor complications. Major complications, other comorbidities, and overall HRQoL did not significantly differ between the groups. Funding: Not applicable.</p

Professional Development and the Informal Curriculum in End-of-Life Care

Although professionalism has emerged as a key competency for today’s physicians, there exists little insight into how best to teach medical students the relevant skills or instill in them the commitment required to practice according to the highest professional standards. Ten UCSF medical students were interviewed at three time points (second, third, and fourth years of school). Interviews focused on students’ learning and development regarding end-of-life care (EOLC). Students described varying steps in their professional development from their second to fourth years of school, including feeling confused about the definition of professionalism and integrating their personal and professional identities. In addition to professional development, four other themes contributed to the development of medical student understanding of how to provide EOLC as a professional: (1) curricular discordance, (2) role models, (3) the tightrope between trained versus human reactions, and (4) ethical dilemmas. These five themes represent dilemmas that students often learned how to respond to over the course of school. Professional development in EOLC required the acquisition of skills necessary to balance the tension between and navigate conflicting messages present in medical student training

Metastatic potential of an aneurysmal bone cyst

Aneurysmal bone cysts (ABCs) are benign bone tumors consisting of blood-filled cavities lined by connective tissue septa. Recently, the hypothesis that ABCs are lesions reactive to local hemodynamics has been challenged after the discovery of specific recurrent chromosomal abnormalities. Multiple cases of malignant transformation of ABC into (osteo)sarcoma have been described, as well as a number of cases of telangiectatic osteosarcoma which had been misdiagnosed as ABC. We herewith document a case of a pelvic ABC metastatic to the lung, liver, and kidneys. Diagnosis was confirmed by the presence of a break in the USP6 gene, which is pathognomonic for ABC, in a pulmonary metastasis of our patient. Sarcomatous transformation as an explanation for this behavior was ruled out by demonstrating diploid DNA content in both the pulmonary lesion and the primary tumor

Differences in Disease Severity but Similar Telomere Lengths in Genetic Subgroups of Patients with Telomerase and Shelterin Mutations

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