Liver-specific deletion of de novo DNA methyltransferases protects against glucose intolerance in high-fat diet-fed male mice.

Alterations to gene transcription and DNA methylation are a feature of many liver diseases including fatty liver disease and liver cancer. However, it is unclear whether the DNA methylation changes are a cause or a consequence of the transcriptional changes. It is even possible that the methylation changes are not required for the transcriptional changes. If DNA methylation is just a minor player in, or a consequence of liver transcriptional change, then future studies in this area should focus on other systems such as histone tail modifications. To interrogate the importance of de novo DNA methylation, we generated mice that are homozygous mutants for both Dnmt3a and Dnmt3b in post-natal liver. These mice are viable and fertile with normal sized livers. Males, but not females, showed increased adipose depots, yet paradoxically, improved glucose tolerance on both control diet and high-fat diets (HFD). Comparison of the transcriptome and methylome with RNA sequencing and whole-genome bisulfite sequencing in adult hepatocytes revealed that widespread loss of methylation in CpG-rich regions in the mutant did not induce loss of homeostatic transcriptional regulation. Similarly, extensive transcriptional changes induced by HFD did not require de novo DNA methylation. The improved metabolic phenotype of the Dnmt3a/3b mutant mice may be mediated through the dysregulation of a subset of glucose and fat metabolism genes which increase both glucose uptake and lipid export by the liver. However, further work is needed to confirm this.

Efficacy and Safety of Dapagliflozin in Patients With Acute Heart Failure.

BACKGROUND: The primary goals during acute heart failure (AHF) hospitalization are decongestion and guideline-directed medical therapy (GDMT) optimization. Unlike diuretics or other GDMT, early dapagliflozin initiation could achieve both AHF goals. OBJECTIVES: The authors aimed to assess the diuretic efficacy and safety of early dapagliflozin initiation in AHF. METHODS: In a multicenter, open-label study, 240 patients were randomized within 24 hours of hospital presentation for hypervolemic AHF to dapagliflozin 10 mg once daily or structured usual care with protocolized diuretic titration until day 5 or hospital discharge. The primary outcome, diuretic efficiency expressed as cumulative weight change per cumulative loop diuretic dose, was compared across treatment assignment using a proportional odds model adjusted for baseline weight. Secondary and safety outcomes were adjudicated by a blinded committee. RESULTS: For diuretic efficiency, there was no difference between dapagliflozin and usual care (OR: 0.65; 95% CI: 0.41-1.02; P = 0.06). Dapagliflozin was associated with reduced loop diuretic doses (560 mg [Q1-Q3: 260-1,150 mg] vs 800 mg [Q1-Q3: 380-1,715 mg]; P = 0.006) and fewer intravenous diuretic up-titrations (P ≤ 0.05) to achieve equivalent weight loss as usual care. Early dapagliflozin initiation did not increase diabetic, renal, or cardiovascular safety events. Dapagliflozin was associated with improved median 24-hour natriuresis (P = 0.03) and urine output (P = 0.005), expediting hospital discharge over the study period. CONCLUSIONS: Early dapagliflozin during AHF hospitalization is safe and fulfills a component of GDMT optimization. Dapagliflozin was not associated with a statistically significant reduction in weight-based diuretic efficiency but was associated with evidence for enhanced diuresis among patients with AHF. (Efficacy and Safety of Dapagliflozin in Acute Heart Failure [DICTATE-AHF]; NCT04298229).

Tissue informative cell-free DNA methylation sites in amyotrophic lateral sclerosis.

Cell-free DNA (cfDNA) is increasingly recognized as a promising biomarker candidate for disease monitoring. However, its utility in neurodegenerative diseases, like amyotrophic lateral sclerosis (ALS), remains underexplored. Existing biomarker discovery approaches are tailored to a specific disease context or are too expensive to be clinically practical. Here, we address these challenges through a new approach combining advances in molecular and computational technologies. First, we develop statistical tools to select tissue-informative DNA methylation sites relevant to a disease process of interest. We then employ a capture protocol to select these sites and perform targeted methylation sequencing. Multi-modal information about the DNA methylation patterns are then utilized in machine learning algorithms trained to predict disease status and disease progression. We applied our method to two independent cohorts of ALS patients and controls (n=192). Overall, we found that the targeted sites accurately predicted ALS status and replicated between cohorts. Additionally, we identified epigenetic features associated with ALS phenotypes, including disease severity. These findings highlight the potential of cfDNA as a non-invasive biomarker for ALS.

Early Utilization of Mechanical Circulatory Support in Acute Myocardial Infarction Complicated by Cardiogenic Shock: The National Cardiogenic Shock Initiative.

BACKGROUND: Acute myocardial infarction complicated by cardiogenic shock (AMI-CS) is associated with significant morbidity and mortality. Mechanical circulatory support (MCS) devices increase systemic blood pressure and end organ perfusion while reducing cardiac filling pressures. METHODS AND RESULTS: The National Cardiogenic Shock Initiative (NCT03677180) is a single-arm, multicenter study. The purpose of this study was to assess the feasibility and effectiveness of utilizing early MCS with Impella in patients presenting with AMI-CS. The primary end point was in-hospital mortality. A total of 406 patients were enrolled at 80 sites between 2016 and 2020. Average age was 64±12 years, 24% were female, 17% had a witnessed out-of-hospital cardiac arrest, 27% had in-hospital cardiac arrest, and 9% were under active cardiopulmonary resuscitation during MCS implantation. Patients presented with a mean systolic blood pressure of 77.2±19.2 mm Hg, 85% of patients were on vasopressors or inotropes, mean lactate was 4.8±3.9 mmol/L and cardiac power output was 0.67±0.29 watts. At 24 hours, mean systolic blood pressure improved to 103.9±17.8 mm Hg, lactate to 2.7±2.8 mmol/L, and cardiac power output to 1.0±1.3 watts. Procedural survival, survival to discharge, survival to 30 days, and survival to 1 year were 99%, 71%, 68%, and 53%, respectively. CONCLUSIONS: Early use of MCS in AMI-CS is feasible across varying health care settings and resulted in improvements to early hemodynamics and perfusion. Survival rates to hospital discharge were high. Given the encouraging results from our analysis, randomized clinical trials are warranted to assess the role of utilizing early MCS, using a standardized, multidisciplinary approach.

Heparin desensitisation prior to cardiopulmonary bypass in a patient with alpha-gal allergy.

This case report describes the implementation of a heparin desensitisation strategy for a patient with confirmed galactose-alpha-1,3-galactose (alpha-gal) allergy, prior to cardiac surgery. We describe the pre-, intra- and postoperative management. We believe this report can enhance the limited data currently in existence on alternative strategies for heparin utilisation in cardiopulmonary bypass in a previously intolerant patient population.

Effect of a Hospital and Postdischarge Quality Improvement Intervention on Clinical Outcomes and Quality of Care for Patients With Heart Failure With Reduced Ejection Fraction: The CONNECT-HF Randomized Clinical Trial.

Importance: Adoption of guideline-directed medical therapy for patients with heart failure is variable. Interventions to improve guideline-directed medical therapy have failed to consistently achieve target metrics, and limited data exist to inform efforts to improve heart failure quality of care. Objective: To evaluate the effect of a hospital and postdischarge quality improvement intervention compared with usual care on heart failure outcomes and care. Design, Setting, and Participants: This cluster randomized clinical trial was conducted at 161 US hospitals and included 5647 patients (2675 intervention vs 2972 usual care) followed up after a hospital discharge for acute heart failure with reduced ejection fraction (HFrEF). The trial was performed from 2017 to 2020, and the date of final follow-up was August 31, 2020. Interventions: Hospitals (n = 82) randomized to a hospital and postdischarge quality improvement intervention received regular education of clinicians by a trained group of heart failure and quality improvement experts and audit and feedback on heart failure process measures (eg, use of guideline-directed medical therapy for HFrEF) and outcomes. Hospitals (n = 79) randomized to usual care received access to a generalized heart failure education website. Main Outcomes and Measures: The coprimary outcomes were a composite of first heart failure rehospitalization or all-cause mortality and change in an opportunity-based composite score for heart failure quality (percentage of recommendations followed). Results: Among 5647 patients (mean age, 63 years; 33% women; 38% Black; 87% chronic heart failure; 49% recent heart failure hospitalization), vital status was known for 5636 (99.8%). Heart failure rehospitalization or all-cause mortality occurred in 38.6% in the intervention group vs 39.2% in usual care (adjusted hazard ratio, 0.92 [95% CI, 0.81 to 1.05). The baseline quality-of-care score was 42.1% vs 45.5%, respectively, and the change from baseline to follow-up was 2.3% vs -1.0% (difference, 3.3% [95% CI, -0.8% to 7.3%]), with no significant difference between the 2 groups in the odds of achieving a higher composite quality score at last follow-up (adjusted odds ratio, 1.06 [95% CI, 0.93 to 1.21]). Conclusions and Relevance: Among patients with HFrEF in hospitals randomized to a hospital and postdischarge quality improvement intervention vs usual care, there was no significant difference in time to first heart failure rehospitalization or death, or in change in a composite heart failure quality-of-care score. Trial Registration: ClinicalTrials.gov Identifier: NCT03035474.

Care Optimization Through Patient and Hospital Engagement Clinical Trial for Heart Failure: Rationale and design of CONNECT-HF.

Many therapies have been shown to improve outcomes for patients with heart failure (HF) in controlled settings, but there are limited data available to inform best practices for hospital and post-discharge quality improvement initiatives. The CONNECT-HF study is a prospective, cluster-randomized trial of 161 hospitals in the United States with a 2×2 factorial design. The study is designed to assess the effect of a hospital and post-discharge quality improvement intervention compared with usual care (primary objective) on HF outcomes and quality-of-care, as well as to evaluate the effect of hospitals implementing a patient-level digital intervention compared with usual care (secondary objective). The hospital and post-discharge intervention includes audit and feedback on HF clinical process measures and outcomes for patients with HF with reduced ejection fraction (HFrEF) paired with education to sites and clinicians by a trained, nationally representative group of HF and quality improvement experts. The patient-level digital intervention is an optional ancillary study and includes a mobile application and behavioral tools that are intended to facilitate improved use of guideline-directed recommendations for self-monitoring and self-management of activity and medications for HFrEF. The effects of the interventions will be measured through an opportunity-based composite score on quality and time-to-first HF readmission or death among patients with HFrEF who present to study hospitals with acute HF and who consent to participate. The CONNECT-HF study is evaluating approaches for implementing HF guideline recommendations into practice and is one of the largest HF implementation science trials performed to date.

Socio-demographic and clinical determinants of dementia in the oldest old: National survey of ageing and cognition in Trinidad

Objective: To determine social and clinical factors associated with dementia in the oldest old (>85 years). Design and Methodology: A survey in a nationally representative sample of people aged 85 years and older using household enumeration was undertaken. Dementia status was ascertained using standardized interviews and algorithms from the 10/66 schedule. Information was also obtained on age, gender, level of education, ethnicity and previous occupation. Self-report on the presence of angina, heart disease, stroke, diabetes, high cholesterol, and hypertension was elicited and corroborated. Results: Of the participants 61.5% were females. The mean age was 89.0 years and dementia was present in 47.2 % persons. Dementia was significantly associated with age >95 (OR=2.02; 95%CI: 0.86- 4.69), female gender (OR=1.31; 95%CI: 0.85- 2.02), East Indian ethnicity (OR=1.45; 95%CI: 0.81-2.60), being widowed (OR=2.05; 95%CI: 0.59-7), Hindu religion (OR=2.10; 95%CI: 1.23- 3.58), history of working in the agricultural sector (OR=3.20; 95%CI: 1.59-6.48). Level of education (OR=0.14; 95%CI: 0.04-0.45), taking vitamins (OR=0.61; 95% CI: 0.37-0.97) and being of mixed ethnicity (African and East Indian) were protective factors. Of the self-reported disease conditions, those with greater than 3 medical co-morbidities were 2 times (OR=2.21; 95%CI: 0.48-9.94) more likely to have dementia than those with0-2 medical comorbidities. Dementia was not more likely to occur in diabetes (OR= 1.03; 95% CI: 0.65-1.64) and hypertension (OR= 0.67; 95% CI: 0.41-1.08). Conclusion: Our study, the first of its kind in Trinidad, supports more tailored policy and better planning of services for a rapidly expanding older population.

A DNA methylation biomarker of alcohol consumption.

The lack of reliable measures of alcohol intake is a major obstacle to the diagnosis and treatment of alcohol-related diseases. Epigenetic modifications such as DNA methylation may provide novel biomarkers of alcohol use. To examine this possibility, we performed an epigenome-wide association study of methylation of cytosine-phosphate-guanine dinucleotide (CpG) sites in relation to alcohol intake in 13 population-based cohorts (ntotal=13 317; 54% women; mean age across cohorts 42-76 years) using whole blood (9643 European and 2423 African ancestries) or monocyte-derived DNA (588 European, 263 African and 400 Hispanic ancestry) samples. We performed meta-analysis and variable selection in whole-blood samples of people of European ancestry (n=6926) and identified 144 CpGs that provided substantial discrimination (area under the curve=0.90-0.99) for current heavy alcohol intake (⩾42 g per day in men and ⩾28 g per day in women) in four replication cohorts. The ancestry-stratified meta-analysis in whole blood identified 328 (9643 European ancestry samples) and 165 (2423 African ancestry samples) alcohol-related CpGs at Bonferroni-adjusted P<1 × 10-7. Analysis of the monocyte-derived DNA (n=1251) identified 62 alcohol-related CpGs at P<1 × 10-7. In whole-blood samples of people of European ancestry, we detected differential methylation in two neurotransmitter receptor genes, the γ-Aminobutyric acid-A receptor delta and γ-aminobutyric acid B receptor subunit 1; their differential methylation was associated with expression levels of a number of genes involved in immune function. In conclusion, we have identified a robust alcohol-related DNA methylation signature and shown the potential utility of DNA methylation as a clinically useful diagnostic test to detect current heavy alcohol consumption.

An epigenome-wide association study meta-analysis of educational attainment.

The epigenome is associated with biological factors, such as disease status, and environmental factors, such as smoking, alcohol consumption and body mass index. Although there is a widespread perception that environmental influences on the epigenome are pervasive and profound, there has been little evidence to date in humans with respect to environmental factors that are biologically distal. Here we provide evidence on the associations between epigenetic modifications-in our case, CpG methylation-and educational attainment (EA), a biologically distal environmental factor that is arguably among the most important life-shaping experiences for individuals. Specifically, we report the results of an epigenome-wide association study meta-analysis of EA based on data from 27 cohort studies with a total of 10 767 individuals. We find nine CpG probes significantly associated with EA. However, robustness analyses show that all nine probes have previously been found to be associated with smoking. Only two associations remain when we perform a sensitivity analysis in the subset of never-smokers, and these two probes are known to be strongly associated with maternal smoking during pregnancy, and thus their association with EA could be due to correlation between EA and maternal smoking. Moreover, the effect sizes of the associations with EA are far smaller than the known associations with the biologically proximal environmental factors alcohol consumption, body mass index, smoking and maternal smoking during pregnancy. Follow-up analyses that combine the effects of many probes also point to small methylation associations with EA that are highly correlated with the combined effects of smoking. If our findings regarding EA can be generalized to other biologically distal environmental factors, then they cast doubt on the hypothesis that such factors have large effects on the epigenome.

Giant electron-hole transport asymmetry in ultra-short quantum transistors.

Making use of bipolar transport in single-wall carbon nanotube quantum transistors would permit a single device to operate as both a quantum dot and a ballistic conductor or as two quantum dots with different charging energies. Here we report ultra-clean 10 to 100 nm scale suspended nanotube transistors with a large electron-hole transport asymmetry. The devices consist of naked nanotube channels contacted with sections of tube under annealed gold. The annealed gold acts as an n-doping top gate, allowing coherent quantum transport, and can create nanometre-sharp barriers. These tunnel barriers define a single quantum dot whose charging energies to add an electron or a hole are vastly different (e-h charging energy asymmetry). We parameterize the e-h transport asymmetry by the ratio of the hole and electron charging energies ηe-h. This asymmetry is maximized for short channels and small band gap tubes. In a small band gap device, we demonstrate the fabrication of a dual functionality quantum device acting as a quantum dot for holes and a much longer quantum bus for electrons. In a 14 nm-long channel, ηe-h reaches up to 2.6 for a device with a band gap of 270 meV. The charging energies in this device exceed 100 meV.

ENT and airways in the emergency department: national survey of junior doctors' knowledge and skills.

BACKGROUND: Given the urgent nature of ENT emergencies, appropriate knowledge is required amongst front-line staff. Junior doctors account for almost one quarter of emergency department doctors. It has been shown that undergraduate coverage of ENT is variable. This study therefore aimed to determine whether emergency department junior doctors were confident in dealing with ENT emergencies, with special focus on the airway. METHOD: An online survey was circulated to junior doctors working in emergency medicine, at the discretion of their training co-ordinators. RESULTS: A total of 104 responses were received. Junior doctors were not confident in managing patients who have undergone tracheostomy or laryngectomy. Management of stridor varied, with 51 per cent giving oxygen and only 77 per cent referring such patients as an emergency to ENT. Most training on the management of airway emergencies was not provided through hospital induction. CONCLUSION: Training should be provided to junior doctors starting work in the emergency department. We suggest mandatory multidisciplinary induction training for such staff.

Genome-wide autozygosity is associated with lower general cognitive ability.

Inbreeding depression refers to lower fitness among offspring of genetic relatives. This reduced fitness is caused by the inheritance of two identical chromosomal segments (autozygosity) across the genome, which may expose the effects of (partially) recessive deleterious mutations. Even among outbred populations, autozygosity can occur to varying degrees due to cryptic relatedness between parents. Using dense genome-wide single-nucleotide polymorphism (SNP) data, we examined the degree to which autozygosity associated with measured cognitive ability in an unselected sample of 4854 participants of European ancestry. We used runs of homozygosity-multiple homozygous SNPs in a row-to estimate autozygous tracts across the genome. We found that increased levels of autozygosity predicted lower general cognitive ability, and estimate a drop of 0.6 s.d. among the offspring of first cousins (P=0.003-0.02 depending on the model). This effect came predominantly from long and rare autozygous tracts, which theory predicts as more likely to be deleterious than short and common tracts. Association mapping of autozygous tracts did not reveal any specific regions that were predictive beyond chance after correcting for multiple testing genome wide. The observed effect size is consistent with studies of cognitive decline among offspring of known consanguineous relationships. These findings suggest a role for multiple recessive or partially recessive alleles in general cognitive ability, and that alleles decreasing general cognitive ability have been selected against over evolutionary time.

A randomised comparison between an inexpensive, general-purpose headlight and a purpose-built surgical headlight on users' visual acuity and colour vision.

To determine if there are any differences in near visual acuity and colour vision between an inexpensive general-purpose light emitting diode (LED) headlight and a purpose-built surgical LED headlight. A prospective study was conducted sequentially comparing near visual acuity and colour vision, the headlights being tested in random order, in a testing room with a constant minimal amount of background light. The participants were NHS employee volunteers, with self-declared normal (or corrected) vision, working in occupations requiring full literacy. For visual acuity, outcome was measured by recording the smallest font legible when using each headlight when the subject read a near visual acuity test card. For colour vision, the outcome was passing or failing the Ishihara test. There was no statistically significant difference between the general-purpose and the purpose-built headlights in users' near visual acuity or colour vision.

708 Common and 2010 rare DISC1 locus variants identified in 1542 subjects: analysis for association with psychiatric disorder and cognitive traits.

A balanced t(1;11) translocation that transects the Disrupted in schizophrenia 1 (DISC1) gene shows genome-wide significant linkage for schizophrenia and recurrent major depressive disorder (rMDD) in a single large Scottish family, but genome-wide and exome sequencing-based association studies have not supported a role for DISC1 in psychiatric illness. To explore DISC1 in more detail, we sequenced 528 kb of the DISC1 locus in 653 cases and 889 controls. We report 2718 validated single-nucleotide polymorphisms (SNPs) of which 2010 have a minor allele frequency of <1%. Only 38% of these variants are reported in the 1000 Genomes Project European subset. This suggests that many DISC1 SNPs remain undiscovered and are essentially private. Rare coding variants identified exclusively in patients were found in likely functional protein domains. Significant region-wide association was observed between rs16856199 and rMDD (P=0.026, unadjusted P=6.3 × 10(-5), OR=3.48). This was not replicated in additional recurrent major depression samples (replication P=0.11). Combined analysis of both the original and replication set supported the original association (P=0.0058, OR=1.46). Evidence for segregation of this variant with disease in families was limited to those of rMDD individuals referred from primary care. Burden analysis for coding and non-coding variants gave nominal associations with diagnosis and measures of mood and cognition. Together, these observations are likely to generalise to other candidate genes for major mental illness and may thus provide guidelines for the design of future studies.

Monozygotic twins affected with major depressive disorder have greater variance in methylation than their unaffected co-twin.

Our understanding of major depressive disorder (MDD) has focused on the influence of genetic variation and environmental risk factors. Growing evidence suggests the additional role of epigenetic mechanisms influencing susceptibility for complex traits. DNA sequence within discordant monozygotic twin (MZT) pairs is virtually identical; thus, they represent a powerful design for studying the contribution of epigenetic factors to disease liability. The aim of this study was to investigate whether specific methylation profiles in white blood cells could contribute to the aetiology of MDD. Participants were drawn from the Queensland Twin Registry and comprised 12 MZT pairs discordant for MDD and 12 MZT pairs concordant for no MDD and low neuroticism. Bisulphite treatment and genome-wide interrogation of differentially methylated CpG sites using the Illumina Human Methylation 450 BeadChip were performed in WBC-derived DNA. No overall difference in mean global methylation between cases and their unaffected co-twins was found; however, the differences in females was significant (P=0.005). The difference in variance across all probes between affected and unaffected twins was highly significant (P<2.2 × 10⁻¹6), with 52.4% of probes having higher variance in cases (binomial P-value<2.2 × 10⁻¹6). No significant differences in methylation were observed between discordant MZT pairs and their matched concordant MZT (permutation minimum P=0.11) at any individual probe. Larger samples are likely to be needed to identify true associations between methylation differences at specific CpG sites.

Few-hundred GHz carbon nanotube nanoelectromechanical systems (NEMS).

We study 23-30 nm long suspended single-wall carbon nanotube quantum dots and observe both their stretching and bending vibrational modes. We use low-temperature DC electron transport to excite and measure the tubes' bending mode by making use of a positive feedback mechanism between their vibrations and the tunneling electrons. In these nanoelectromechanical systems (NEMS), we measure fundamental bending frequencies f(bend) ≈ 75-280 GHz and extract quality factors Q ∼ 10(6). The NEMS's frequencies can be tuned by a factor of 2 with tension induced by mechanical breakjunctions actuated by an electrostatic force or tension from bent suspended electrodes.

Promoter polymorphisms in two overlapping 6p25 genes implicate mitochondrial proteins in cognitive deficit in schizophrenia.

In a previous study, we detected a 6p25-p24 region linked to schizophrenia in families with high composite cognitive deficit (CD) scores, a quantitative trait integrating multiple cognitive measures. Association mapping of a 10 Mb interval identified a 260 kb region with a cluster of single-nucleotide polymorphisms (SNPs) significantly associated with CD scores and memory performance. The region contains two colocalising genes, LYRM4 and FARS2, both encoding mitochondrial proteins. The two tagging SNPs with strongest evidence of association were located around the overlapping putative promoters, with rs2224391 predicted to alter a transcription factor binding site (TFBS). Sequencing the promoter region identified 22 SNPs, many predicted to affect TFBSs, in a tight linkage disequilibrium block. Luciferase reporter assays confirmed promoter activity in the predicted promoter region, and demonstrated marked downregulation of expression in the LYRM4 direction under the haplotype comprising the minor alleles of promoter SNPs, which however is not driven by rs2224391. Experimental evidence from LYRM4 expression in lymphoblasts, gel-shift assays and modelling of DNA breathing dynamics pointed to two adjacent promoter SNPs, rs7752203-rs4141761, as the functional variants affecting expression. Their C-G alleles were associated with higher transcriptional activity and preferential binding of nuclear proteins, whereas the G-A combination had opposite effects and was associated with poor memory and high CD scores. LYRM4 is a eukaryote-specific component of the mitochondrial biogenesis of Fe-S clusters, essential cofactors in multiple processes, including oxidative phosphorylation. LYRM4 downregulation may be one of the mechanisms involved in inefficient oxidative phosphorylation and oxidative stress, increasingly recognised as contributors to schizophrenia pathogenesis.

Impact of CONSORT extension for cluster randomised trials on quality of reporting and study methodology: review of random sample of 300 trials, 2000-8.

OBJECTIVE: To assess the impact of the 2004 extension of the CONSORT guidelines on the reporting and methodological quality of cluster randomised trials. DESIGN: Methodological review of 300 randomly sampled cluster randomised trials. Two reviewers independently abstracted 14 criteria related to quality of reporting and four methodological criteria specific to cluster randomised trials. We compared manuscripts published before CONSORT (2000-4) with those published after CONSORT (2005-8). We also investigated differences by journal impact factor, type of journal, and trial setting. DATA SOURCES: A validated Medline search strategy. Eligibility criteria for selecting studies Cluster randomised trials published in English language journals, 2000-8. RESULTS: There were significant improvements in five of 14 reporting criteria: identification as cluster randomised; justification for cluster randomisation; reporting whether outcome assessments were blind; reporting the number of clusters randomised; and reporting the number of clusters lost to follow-up. No significant improvements were found in adherence to methodological criteria. Trials conducted in clinical rather than non-clinical settings and studies published in medical journals with higher impact factor or general medical journals were more likely to adhere to recommended reporting and methodological criteria overall, but there was no evidence that improvements after publication of the CONSORT extension for cluster trials were more likely in trials conducted in clinical settings nor in trials published in either general medical journals or in higher impact factor journals. CONCLUSION: The quality of reporting of cluster randomised trials improved in only a few aspects since the publication of the extension of CONSORT for cluster randomised trials, and no improvements at all were observed in essential methodological features. Overall, the adherence to reporting and methodological guidelines for cluster randomised trials remains suboptimal, and further efforts are needed to improve both reporting and methodology.