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Nevin Manimala Statistics

Proof of concept example for use of simulation to allow data pooling despite privacy restrictions

Epidemiology. 2021 Jun 25. doi: 10.1097/EDE.0000000000001373. Online ahead of print.

ABSTRACT

BACKGROUND: Integrating results from multiple samples is often desirable, but privacy restrictions may preclude full data pooling, and most datasets do not include fully harmonized variable sets. We propose a simulation-based method leveraging partial information across datasets to guide creation of synthetic data, based on explicit assumptions about the underlying causal structure, that permits pooled analyses that adjust for all desired confounders in the context of privacy restrictions.

METHODS: This proof-of-concept project uses data from the Health and Retirement Study (HRS) and Atherosclerosis Risk in Communities (ARIC) study. We specified an estimand of interest and a directed acyclic graph (DAG) summarizing the presumed causal structure for the effect of glycated hemoglobin (HbA1c) on cognitive change. We derived publicly reportable statistics to describe the joint distribution of each variable in our DAG. These summary estimates were used as data-generating rules to create synthetic datasets. After pooling, we imputed missing covariates in the synthetic datasets and used the synthetic data to estimate the pooled effect of HbA1c on cognitive change, adjusting for all desired covariates.

RESULTS: Distributions of covariates, as well as model coefficients and associated standard errors for our model estimating the effect of HbA1c on cognitive change were similar across cohort-specific original and pre-imputation synthetic data. The estimate from the pooled synthetic incorporates control for confounders measured in either original dataset.

DISCUSSION: Our approach has advantages over meta-analysis or individual-level pooling/data harmonization when privacy concerns preclude data sharing and key confounders are not uniformly measured across datasets.

PMID:34183527 | DOI:10.1097/EDE.0000000000001373

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Nevin Manimala Statistics

Bronze Age weight systems as a measure of market integration in Western Eurasia

Proc Natl Acad Sci U S A. 2021 Jul 6;118(27):e2105873118. doi: 10.1073/pnas.2105873118.

ABSTRACT

Weighing technology was invented around 3000 BCE between Mesopotamia and Egypt and became widely adopted in Western Eurasia within ∼2,000 y. For the first time in history, merchants could rely on an objective frame of reference to quantify economic value. The subsequent emergence of different weight systems goes hand in hand with the formation of a continental market. However, we still do not know how the technological transmission happened and why different weight systems emerged along the way. Here, we show that the diffusion of weighing technology can be explained as the result of merchants’ interaction and the emergence of primary weight systems as the outcome of the random propagation of error constrained by market self-regulation. We found that the statistical errors of early units between Mesopotamia and Europe overlap significantly. Our experiment with replica weights gives error figures that are consistent with the archaeological sample. We used these figures to develop a model simulating the formation of primary weight systems based on the random propagation of error over time from a single original unit. The simulation is consistent with the observed distribution of weight units. We demonstrate that the creation of the earliest weight systems is not consistent with a substantial intervention of political authorities. Our results urge a revaluation of the role of individual commercial initiatives in the formation of the first integrated market in Western Eurasia.

PMID:34183401 | DOI:10.1073/pnas.2105873118

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Nevin Manimala Statistics

Anti-seizure Drug Levels in Children Aged 2-12 Years Presenting With Breakthrough Seizures: A Single Center Cross-sectional Study

Indian Pediatr. 2021 Jun 28:S097475591600346. Online ahead of print.

ABSTRACT

OBJECTIVE: To study the anti-seizure drug levels and associated factors in children with breakthrough seizures.

METHODS: This cross-sectional study was conducted at a public hospital between November 2017 to April 2019, included 145 children with epilepsy aged 2 to 12 years presenting with breakthrough seizure. Anti-seizure drug levels were measured, and the levels were categorized as within, below, and above the reference range.

RESULTS: Children with epilepsy receiving sodium valproate, phenytoin and carbamazepine were 111 (73%), 31 (20.4%) and 10 (6.6%), respectively, of which 7 were receiving multiple anti-seizure drugs. Drug levels below the reference range were found in 64 (44.1%), within the reference range in 70 (48.3%), and the above reference range in 11 (7.6%) children.

CONCLUSION: Nearly half the children with breakthrough seizures had sub-therapeutic levels, especially those on phenytoin therapy. Drug levels in below therapeutic range do not predict the occurrence of breakthrough seizures.

PMID:34183465

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Nevin Manimala Statistics

Systematic Reviews and Meta-Analysis: A Guide for Beginners

Indian Pediatr. 2021 Jun 28:S097475591600350. Online ahead of print.

ABSTRACT

Systematic reviews involve the application of scientific methods to reduce bias in review of literature. The key components of a systematic review are a well-defined research question, comprehensive literature search to identify all studies that potentially address the question, systematic assembly of the studies that answer the question, critical appraisal of the methodological quality of the included studies, data extraction and analysis (with and without statistics), and considerations towards applicability of the evidence generated in a systematic review. These key features can be remembered as six ‘A’; Ask, Access, Assimilate, Appraise, Analyze and Apply. Meta-analysis is a statistical tool that provides pooled estimates of effect from the data extracted from individual studies in the systematic review. The graphical output of meta-analysis is a forest plot which provides information on individual studies and the pooled effect. Systematic reviews of literature can be undertaken for all types of questions, and all types of study designs. This article highlights the key features of systematic reviews, and is designed to help readers understand and interpret them. It can also help to serve as a beginner’s guide for both users and producers of systematic reviews and to appreciate some of its methodological issues.

PMID:34183469

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Nevin Manimala Statistics

Study protocol for SKIPMDD: subcutaneous ketamine infusion in palliative care patients with advanced life limiting illnesses for major depressive disorder (phase II pilot feasibility study)

BMJ Open. 2021 Jun 28;11(6):e052312. doi: 10.1136/bmjopen-2021-052312.

ABSTRACT

INTRODUCTION: Major depressive disorder (MDD) in people with advanced life-limiting illnesses can have significant impact on the quality-of-life of those affected. The management of MDD in the palliative care setting can be challenging as typical antidepressants may not work in time nor be tolerated due to coexisting organ dysfunctions, symptom burden and frailty. Parenteral ketamine was found to exhibit effective and rapid-onset antidepressant effect even against treatment-resistant depression in the psychiatric population. However, there is currently neither feasibility study nor available prospective study available to inform of the safety, tolerability and efficacy of such for MDD in the palliative setting.

METHODS AND ANALYSIS: This is an open-labelled, single arm, phase II pilot feasibility study involving adult patients with advanced life-limiting illnesses and MDD across four palliative care services in Australia. It has an individual dose-titration design (0.1-0.4 mg/kg) with weekly treatments of subcutaneous ketamine infusion over 2 hours. The primary outcome is feasibility. The secondary outcomes are related to the safety, tolerability and antidepressant efficacy of ketamine, participants’ satisfaction in relation to the trial process and the reasons for not completing the study at various stages. The feasibility data will be reported using descriptive statistics. Meanwhile, side effects, tolerability and efficacy data will be analysed using change of assessment scores from baseline.

ETHICS AND DISSEMINATION: Ethics approval was acquired (South Western Sydney Local Health District: HREC/18/LPOOL/466). The results of this study will be submitted for publication in peer-reviewed journals and presented at relevant conferences.

TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trial Registry Number: ACTRN12618001586202; Pre-results.

PMID:34183351 | DOI:10.1136/bmjopen-2021-052312

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Nevin Manimala Statistics

Genomic and transcriptomic analyses of breast cancer primaries and matched metastases in AURORA, the Breast International Group (BIG) molecular screening initiative

Cancer Discov. 2021 Jun 28:candisc.1647.2020. doi: 10.1158/2159-8290.CD-20-1647. Online ahead of print.

ABSTRACT

AURORA aims to study the processes of relapse in metastatic breast cancer (MBC) by performing multi-omics profiling on paired primary tumors and early-course metastases. Among 381 patients (primary tumor and metastasis pairs: 252 TGS, 152 RNA-Seq, 67 SNP Arrays), we found a driver role for GATA1 and MEN1 somatic mutations. Metastases were enriched in ESR1, PTEN, CDH1, PIK3CA and RB1 mutations; MDM4, MYC amplifications; ARID1A deletions. An increase in clonality was observed in driver genes like ERBB2 and RB1. Intrinsic subtype switching occurred in 36% of cases. Luminal A/B to HER2-Enriched switching was associated with TP53 and/or PIK3CA mutations. Metastases had lower immune score and increased immune permissive cells. High TMB correlated to shorter time to relapse in HR+/HER2- cancers. ESCAT tier I/II alterations were detected in 51% of patients and matched therapy was used in 7%. Integration of multi-omics analyses in clinical practice could impact treatment strategies in MBC.

PMID:34183353 | DOI:10.1158/2159-8290.CD-20-1647

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Nevin Manimala Statistics

EUROlinkCAT protocol for a European population-based data linkage study investigating the survival, morbidity and education of children with congenital anomalies

BMJ Open. 2021 Jun 28;11(6):e047859. doi: 10.1136/bmjopen-2020-047859.

ABSTRACT

INTRODUCTION: Congenital anomalies (CAs) are a major cause of infant mortality, childhood morbidity and long-term disability. Over 130 000 children born in Europe every year will have a CA. This paper describes the EUROlinkCAT study, which is investigating the health and educational outcomes of children with CAs for the first 10 years of their lives.

METHODS AND ANALYSIS: EUROCAT is a European network of population-based registries for the epidemiological surveillance of CAs. EUROlinkCAT is using the EUROCAT infrastructure to support 22 EUROCAT registries in 14 countries to link their data on births with CAs to mortality, hospital discharge, prescription and educational databases. Once linked, each registry transforms their case data into a common data model (CDM) format and they are then supplied with common STATA syntax scripts to analyse their data. The resulting aggregate tables and analysis results are submitted to a central results repository (CRR) and meta-analyses are performed to summarise the results across all registries. The CRR currently contains data on 155 594 children with a CA followed up to age 10 from a population of 6 million births from 1995 to 2014.

ETHICS: The CA registries have the required ethics permissions for routine surveillance and transmission of anonymised data to the EUROCAT central database. Each registry is responsible for applying for and obtaining additional ethics and other permissions required for their participation in EUROlinkCAT.

DISSEMINATION: The CDM and associated documentation, including linkage and standardisation procedures, will be available post-EUROlinkCAT thus facilitating future local, national and European-level analyses to improve healthcare. Recommendations to improve the accuracy of routinely collected data will be made.Findings will provide evidence to inform parents, health professionals, public health authorities and national treatment guidelines to optimise diagnosis, prevention and treatment for these children with a view to reducing health inequalities in Europe.

PMID:34183346 | DOI:10.1136/bmjopen-2020-047859

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Nevin Manimala Statistics

Association of low birth weight with cardiometabolic diseases in Swedish twins: a population-based cohort study

BMJ Open. 2021 Jun 28;11(6):e048030. doi: 10.1136/bmjopen-2020-048030.

ABSTRACT

OBJECTIVES: To examine the association between low birth weight (LBW) and cardiometabolic diseases (CMDs, including heart disease, stroke and type 2 diabetes mellitus) in adulthood, and to explore whether genetic, early-life environmental and healthy lifestyle factors play a role in this association.

DESIGN: A population-based twin study.

SETTING: Twins from the Swedish Twin Registry who were born in 1958 or earlier participated in the Screening Across the Lifespan Twin (SALT) study for a full-scale screening during 1998-2002 and were followed up until 2014.

PARTICIPANTS: 19 779 twin individuals in Sweden with birthweight data available (mean age: 55.45 years).

PRIMARY AND SECONDARY OUTCOME MEASURES: CMDs were assessed based on self-reported medical records, medication use and records from the National Patient Registry. A lifestyle index encompassing smoking status, alcohol consumption, exercise levels and Body Mass Index was derived from the SALT survey and categorised as unfavourable, intermediate or favourable. Data were analysed using generalised estimating equation (GEE) models and conditional logistic regression models.

RESULTS: Of all participants, 3998 (20.2%) had LBW and 5335 (27.0%) had incident CMDs (mean age at onset: 63.64±13.26 years). In GEE models, the OR of any CMD was 1.39 (95% CI 1.27 to 1.52) for LBW. In conditional logistic regression models, the LBW-CMD association became non-significant (OR=1.21, 95% CI 0.94 to 1.56). The difference in ORs from the two models was statistically significant (p<0.001). In the joint effect analysis, the multiadjusted OR of CMDs was 3.47 (95% CI 2.72 to 4.43) for participants with LBW plus an unfavourable lifestyle and 1.25 (95% CI 0.96 to 1.62) for those with LBW plus a favourable lifestyle.

CONCLUSION: LBW is associated with an increased risk of adult CMDs, and genetic and early-life environmental factors may account for this association. However, a favourable lifestyle profile may modify this risk.

PMID:34183347 | DOI:10.1136/bmjopen-2020-048030

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Nevin Manimala Statistics

Progression from external pilot to definitive randomised controlled trial: a methodological review of progression criteria reporting

BMJ Open. 2021 Jun 28;11(6):e048178. doi: 10.1136/bmjopen-2020-048178.

ABSTRACT

OBJECTIVES: Prespecified progression criteria can inform the decision to progress from an external randomised pilot trial to a definitive randomised controlled trial. We assessed the characteristics of progression criteria reported in external randomised pilot trial protocols and results publications, including whether progression criteria were specified a priori and mentioned in prepublication peer reviewer reports.

STUDY DESIGN: Methodological review.

METHODS: We searched four journals through PubMed: British Medical Journal Open, Pilot and Feasibility Studies, Trials and Public Library of Science One. Eligible publications reported external randomised pilot trial protocols or results, were published between January 2018 and December 2019 and reported progression criteria. We double data extracted 25% of the included publications. Here we report the progression criteria characteristics.

RESULTS: We included 160 publications (123 protocols and 37 completed trials). Recruitment and retention were the most frequent indicators contributing to progression criteria. Progression criteria were mostly reported as distinct thresholds (eg, achieving a specific target; 133/160, 83%). Less than a third of the planned and completed pilot trials that included qualitative research reported how these findings would contribute towards progression criteria (34/108, 31%). The publications seldom stated who established the progression criteria (12/160, 7.5%) or provided rationale or justification for progression criteria (44/160, 28%). Most completed pilot trials reported the intention to proceed to a definitive trial (30/37, 81%), but less than half strictly met all of their progression criteria (17/37, 46%). Prepublication peer reviewer reports were available for 153/160 publications (96%). Peer reviewer reports for 86/153 (56%) publications mentioned progression criteria, with peer reviewers of 35 publications commenting that progression criteria appeared not to be specified.

CONCLUSIONS: Many external randomised pilot trial publications did not adequately report or propose prespecified progression criteria to inform whether to proceed to a future definitive randomised controlled trial.

PMID:34183348 | DOI:10.1136/bmjopen-2020-048178

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Nevin Manimala Statistics

Efficacy and safety of hyperbaric oxygen therapy for moderate-to-severe ulcerative colitis: a protocol for a systematic review and meta-analysis

BMJ Open. 2021 Jun 28;11(6):e047543. doi: 10.1136/bmjopen-2020-047543.

ABSTRACT

INTRODUCTION: Ulcerative colitis (UC) is a type of inflammatory bowel disease, and 62% of patients with UC felt that it is difficult for them to live a normal life. Furthermore, some researches have shown that about 15% of patients with UC undergo at least one extreme clinical course in their lifetime, and 10%-30% of patients with UC oblige colectomy. Although many investigations have demonstrated that HBO2 has a beneficial impact on UC treatment, a systematic review and meta-analysis are unavailable. Therefore, a meta-analysis is essential to assess the efficacy and safety of HBO2 in treating UC.

METHODS AND ANALYSIS: A systematic search plan will be performed in the following seven databases with a restriction of time from inception to September 2020 to filter the eligible studies: PubMed, Web of Science, Embase, Cochrane Library, China National Knowledge Infrastructure, Chinese Scientific Journal Database (VIP) and Chinese Biomedical Database WanFang. Other related resources will be also searched. Two independent reviewers will choose eligible researches and extract data. The risk of bias will be evaluated based on Cochrane Collaboration’s Risk of Bias tool and Newcastle-Ottawa Scale. Eventually, a systematic review and meta-analysis will be performed via the Review Manager V.5.3 statistical software and STATA V.14.0 software.

ETHICS AND DISSEMINATION: This study will not involve the individual patient and any ethical problems since its outcomes are based on published data. Therefore, no ethical review and approval are required. We plan to publish the study in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER: CRD42020210244.

PMID:34183344 | DOI:10.1136/bmjopen-2020-047543