PEDIATRICS/statistics Dotaz Zobrazit nápovědu

Přesná shoda

BACKGROUND: Natural history models for primary sclerosing cholangitis (PSC) are derived from adult patient data, but have never been validated in children. It is unclear how accurate such models are for children with PSC. METHODS: We utilized the pediatric PSC consortium database to assess the Revised Mayo Clinic, Amsterdam-Oxford, and Boberg models. We calculated the risk stratum and predicted survival for each patient within each model using patient data at PSC diagnosis, and compared it with observed survival. We evaluated model fit using the c-statistic. RESULTS: Model fit was good at 1 year (c-statistics 0.93, 0.87, 0.82) and fair at 10 years (0.78, 0.75, 0.69) in the Mayo, Boberg, and Amsterdam-Oxford models, respectively. The Mayo model correctly classified most children as low risk, whereas the Amsterdam-Oxford model incorrectly classified most as high risk. All of the models underestimated survival of patients classified as high risk. Albumin, bilirubin, AST, and platelets were most associated with outcomes. Autoimmune hepatitis was more prevalent in higher risk groups, and over-weighting of AST in these patients accounted for the observed versus predicted survival discrepancy. CONCLUSIONS: All 3 models offered good short-term discrimination of outcomes but only fair long-term discrimination. None of the models account for the high prevalence of features of autoimmune hepatitis overlap in children and the associated elevated aminotransferases. A pediatric-specific model is needed. AST, bilirubin, albumin, and platelets will be important predictors, but must be weighted to account for the unique features of PSC in children.

MeSH
autoimunitní hepatitida komplikace mortalita MeSH
dítě MeSH
gastroenterologie metody MeSH
hodnocení rizik metody MeSH
jaterní testy metody MeSH
Kaplanův-Meierův odhad MeSH
lidé MeSH
pediatrie metody MeSH
prediktivní hodnota testů MeSH
prognóza MeSH
reprodukovatelnost výsledků MeSH
sklerozující cholangitida komplikace mortalita MeSH
statistické modely * MeSH
Check Tag
dítě MeSH
lidé MeSH
mužské pohlaví MeSH
ženské pohlaví MeSH
Publikační typ
časopisecké články MeSH
hodnotící studie MeSH
práce podpořená grantem MeSH
Research Support, N.I.H., Extramural MeSH

Článek

Compositional data analysis for physical activity, sedentary time and sleep research

Statistical methods in medical research. 2018 Dec ; 27 (12) : 3726-3738. [epub] 20170530

Stat Methods Med Res
ISSN 1477-0334 | 0962-2802
Zdroj

The health effects of daily activity behaviours (physical activity, sedentary time and sleep) are widely studied. While previous research has largely examined activity behaviours in isolation, recent studies have adjusted for multiple behaviours. However, the inclusion of all activity behaviours in traditional multivariate analyses has not been possible due to the perfect multicollinearity of 24-h time budget data. The ensuing lack of adjustment for known effects on the outcome undermines the validity of study findings. We describe a statistical approach that enables the inclusion of all daily activity behaviours, based on the principles of compositional data analysis. Using data from the International Study of Childhood Obesity, Lifestyle and the Environment, we demonstrate the application of compositional multiple linear regression to estimate adiposity from children's daily activity behaviours expressed as isometric log-ratio coordinates. We present a novel method for predicting change in a continuous outcome based on relative changes within a composition, and for calculating associated confidence intervals to allow for statistical inference. The compositional data analysis presented overcomes the lack of adjustment that has plagued traditional statistical methods in the field, and provides robust and reliable insights into the health effects of daily activity behaviours.

Klíčová slova
Compositional data analysis, multicollinearity, physical activity, sedentary behaviour, sleep,
MeSH
cvičení * MeSH
dítě MeSH
interpretace statistických dat * MeSH
lidé MeSH
obezita dětí a dospívajících * MeSH
sedavý životní styl * MeSH
spánek * MeSH
Check Tag
dítě MeSH
lidé MeSH
Publikační typ
časopisecké články MeSH
práce podpořená grantem MeSH

Článek

The compositional isotemporal substitution model: A method for estimating changes in a health outcome for reallocation of time between sleep, physical activity and sedentary behaviour

Statistical methods in medical research. 2019 Mar ; 28 (3) : 846-857. [epub] 20171120

Stat Methods Med Res
ISSN 1477-0334 | 0962-2802
Zdroj

How people use their time has been linked with their health. For example, spending more time being physically active is known to be beneficial for health, whereas long durations of sitting have been associated with unfavourable health outcomes. Accordingly, public health messages have advocated swapping strategies to promote the reallocation of time between parts of the time-use composition, such as "Move More, Sit Less", with the aim of achieving optimal distribution of time for health. However, the majority of research underpinning these public health messages has not considered daily time use as a composition, and has ignored the relative nature of time-use data. We present a way of applying compositional data analysis to estimate change in a health outcome when fixed durations of time are reallocated from one part of a particular time-use composition to another, while the remaining parts are kept constant, based on a multiple linear regression model on isometric log ratio coordinates. In an example, we examine the expected differences in Body Mass Index z-scores for reallocations of time between sleep, physical activity and sedentary behaviour.

Klíčová slova
Isotemporal substitution, compositional data, physical activity, sedentary behaviour, sleep, time use,
MeSH
algoritmy MeSH
cvičení * MeSH
lidé MeSH
obezita dětí a dospívajících MeSH
organizace času * MeSH
sedavý životní styl * MeSH
spánek * MeSH
statistické modely * MeSH
zdravotní stav MeSH
životní styl MeSH
Check Tag
lidé MeSH
Publikační typ
časopisecké články MeSH
práce podpořená grantem MeSH

Publikováno

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