6,778 research outputs found
Risk of postoperative acute kidney injury in patients undergoing orthopaedic surgery—development and validation of a risk score and effect of acute kidney injury on survival:observational cohort study
Funding: This study was funded by Tenovus Tayside, Chief Scientist Office, Scotland and a travelling fellowship from the Royal College of Physicians and Surgeons of Glasgow. The funders had no role in the study design; collection, analysis, and interpretation of the data; writing of the report; or the decision to submit the article for publication. The researchers are independent of the funders.Non peer reviewedPublisher PD
Estimation of causal effects using instrumental variables with nonignorable missing covariates: Application to effect of type of delivery NICU on premature infants
Understanding how effective high-level NICUs (neonatal intensive care units
that have the capacity for sustained mechanical assisted ventilation and high
volume) are compared to low-level NICUs is important and valuable for both
individual mothers and for public policy decisions. The goal of this paper is
to estimate the effect on mortality of premature babies being delivered in a
high-level NICU vs. a low-level NICU through an observational study where there
are unmeasured confounders as well as nonignorable missing covariates. We
consider the use of excess travel time as an instrumental variable (IV) to
control for unmeasured confounders. In order for an IV to be valid, we must
condition on confounders of the IV---outcome relationship, for example, month
prenatal care started must be conditioned on for excess travel time to be a
valid IV. However, sometimes month prenatal care started is missing, and the
missingness may be nonignorable because it is related to the not fully measured
mother's/infant's risk of complications. We develop a method to estimate the
causal effect of a treatment using an IV when there are nonignorable missing
covariates as in our data, where we allow the missingness to depend on the
fully observed outcome as well as the partially observed compliance class,
which is a proxy for the unmeasured risk of complications. A simulation study
shows that under our nonignorable missingness assumption, the commonly used
estimation methods, complete-case analysis and multiple imputation by chained
equations assuming missingness at random, provide biased estimates, while our
method provides approximately unbiased estimates. We apply our method to the
NICU study and find evidence that high-level NICUs significantly reduce deaths
for babies of small gestational age, whereas for almost mature babies like 37
weeks, the level of NICUs makes little difference. A sensitivity analysis is
conducted to assess the sensitivity of our conclusions to key assumptions about
the missing covariates. The method we develop in this paper may be useful for
many observational studies facing similar issues of unmeasured confounders and
nonignorable missing data as ours.Comment: Published in at http://dx.doi.org/10.1214/13-AOAS699 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Simultaneous Measurement Imputation and Outcome Prediction for Achilles Tendon Rupture Rehabilitation
Achilles Tendon Rupture (ATR) is one of the typical soft tissue injuries.
Rehabilitation after such a musculoskeletal injury remains a prolonged process
with a very variable outcome. Accurately predicting rehabilitation outcome is
crucial for treatment decision support. However, it is challenging to train an
automatic method for predicting the ATR rehabilitation outcome from treatment
data, due to a massive amount of missing entries in the data recorded from ATR
patients, as well as complex nonlinear relations between measurements and
outcomes. In this work, we design an end-to-end probabilistic framework to
impute missing data entries and predict rehabilitation outcomes simultaneously.
We evaluate our model on a real-life ATR clinical cohort, comparing with
various baselines. The proposed method demonstrates its clear superiority over
traditional methods which typically perform imputation and prediction in two
separate stages
Synthetic Observational Health Data with GANs: from slow adoption to a boom in medical research and ultimately digital twins?
After being collected for patient care, Observational Health Data (OHD) can
further benefit patient well-being by sustaining the development of health
informatics and medical research. Vast potential is unexploited because of the
fiercely private nature of patient-related data and regulations to protect it.
Generative Adversarial Networks (GANs) have recently emerged as a
groundbreaking way to learn generative models that produce realistic synthetic
data. They have revolutionized practices in multiple domains such as
self-driving cars, fraud detection, digital twin simulations in industrial
sectors, and medical imaging.
The digital twin concept could readily apply to modelling and quantifying
disease progression. In addition, GANs posses many capabilities relevant to
common problems in healthcare: lack of data, class imbalance, rare diseases,
and preserving privacy. Unlocking open access to privacy-preserving OHD could
be transformative for scientific research. In the midst of COVID-19, the
healthcare system is facing unprecedented challenges, many of which of are data
related for the reasons stated above.
Considering these facts, publications concerning GAN applied to OHD seemed to
be severely lacking. To uncover the reasons for this slow adoption, we broadly
reviewed the published literature on the subject. Our findings show that the
properties of OHD were initially challenging for the existing GAN algorithms
(unlike medical imaging, for which state-of-the-art model were directly
transferable) and the evaluation synthetic data lacked clear metrics.
We find more publications on the subject than expected, starting slowly in
2017, and since then at an increasing rate. The difficulties of OHD remain, and
we discuss issues relating to evaluation, consistency, benchmarking, data
modelling, and reproducibility.Comment: 31 pages (10 in previous version), not including references and
glossary, 51 in total. Inclusion of a large number of recent publications and
expansion of the discussion accordingl
Machine Learning and Integrative Analysis of Biomedical Big Data.
Recent developments in high-throughput technologies have accelerated the accumulation of massive amounts of omics data from multiple sources: genome, epigenome, transcriptome, proteome, metabolome, etc. Traditionally, data from each source (e.g., genome) is analyzed in isolation using statistical and machine learning (ML) methods. Integrative analysis of multi-omics and clinical data is key to new biomedical discoveries and advancements in precision medicine. However, data integration poses new computational challenges as well as exacerbates the ones associated with single-omics studies. Specialized computational approaches are required to effectively and efficiently perform integrative analysis of biomedical data acquired from diverse modalities. In this review, we discuss state-of-the-art ML-based approaches for tackling five specific computational challenges associated with integrative analysis: curse of dimensionality, data heterogeneity, missing data, class imbalance and scalability issues
Effectiveness and cost-effectiveness of a novel, group self-management course for adults with chronic musculoskeletal pain: study protocol for a multicentre, randomised controlled trial (COPERS)
Introduction: Chronic musculoskeletal pain is a
common condition that often responds poorly to
treatment. Self-management courses have been
advocated as a non-drug pain management
technique, although evidence for their effectiveness
is equivocal. We designed and piloted a
self-management course based on evidence for
effectiveness for specific course components and
characteristics.
Methods/analysis: COPERS (coping with persistent
pain, effectiveness research into self-management) is
a pragmatic randomised controlled trial testing the
effectiveness and cost-effectiveness of an intensive,
group, cognitive behavioural-based, theoretically
informed and manualised self-management course
for chronic pain patients against a control of best
usual care: a pain education booklet and a relaxation
CD. The course lasts for 15 h, spread over 3 days,
with a –2 h follow-up session 2 weeks later. We aim
to recruit 685 participants with chronic
musculoskeletal pain from primary, intermediate and
secondary care services in two UK regions. The
study is powered to show a standardised mean
difference of 0.3 in the primary outcome, pain-related
disability. Secondary outcomes include generic
health-related quality of life, healthcare utilisation,
pain self-efficacy, coping, depression, anxiety and
social engagement. Outcomes are measured at 6 and
12 months postrandomisation. Pain self-efficacy is
measured at 3 months to assess whether change
mediates clinical effect.
Ethics/dissemination: Ethics approval was given
by Cambridgeshire Ethics 11/EE/046. This trial will
provide robust data on the effectiveness and
cost-effectiveness of an evidence-based, group
self-management programme for chronic
musculoskeletal pain. The published outcomes will
help to inform future policy and practice around such
self-management courses, both nationally and
internationally.
Trial registration: ISRCTN24426731
Deep Recurrent Neural Networks for Mortality Prediction in Intensive Care using Clinical Time Series at Multiple Resolutions
Mortality models in Intensive Care Units (ICU) are important for clinical decision support tasks such as identifying high-risk patients and prioritizing their care. Previous mortality models have used predictive variables mainly from Electronic Medical Records (EMR) where each patient observation can be represented as a sparse multivariate time series. Bedside monitors are another common data source in ICUs containing high-resolution time series, which have not been explored in combination with EMR data for mortality modelling. We take the first step towards building such a model. Specialized techniques developed for sparse time series cannot be used to model multiple time series at different resolutions. To address this problem, we develop MTS-RNN, a new deep recurrent neural network architecture. Our preliminary experiments on real clinical data show that MTS-RNN outperforms state-of-the-art mortality models in predictive accuracy, highlighting the importance of using clinical time series at multiple resolutions for ICU mortality prediction
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