In survival studies, information lost through censoring can be partially recaptured through repeated measures data which are predictive of survival. In addition, such data may be useful in removing bias in survival estimates, due to censoring which depends upon the repeated measures. Here we investigate joint models for survival T and repeated measurements Y, given a vector of covariates Z. Mixture models indexed as f (T/Z) f (Y/T,Z) are well suited for assessing covariate effects on survival time. Our objective is efficiency gains, using non-parametric models for Y in order to avoid introducing bias by misspecification of the distribution for Y. We model (T/Z) as a piecewise exponential distribution with proportional hazards covariate effect. The component (Y/T,Z) has a multinomial model. The joint likelihood for survival and longitudinal data is maximized, using the EM algorithm. The estimate of covariate effect is compared to the estimate based on the standard proportional hazards model and an alternative joint model based estimate. We demonstrate modest gains in efficiency when using the joint piecewise exponential joint model. In a simulation, the estimated efficiency gain over the standard proportional hazards model is 6.4 per cent. In clinical trial data, the estimated efficiency gain over the standard proportional hazards model is 10.2 per cent.
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http://dx.doi.org/10.1002/sim.1439 | DOI Listing |
JAMA Pediatr
January 2025
Division of Nephrology, The Hospital for Sick Children, Toronto, Ontario, Canada.
Importance: Cyclophosphamide and calcineurin inhibitors are the most used nonsteroid immunosuppressive medications globally for children with various chronic inflammatory conditions. Their comparative effectiveness remains uncertain, leading to worldwide practice variation. Nephrotic syndrome is the most common kidney disease managed by pediatricians globally and suboptimal treatment is associated with high morbidity.
View Article and Find Full Text PDFAIDS Behav
January 2025
Guangzhou Center for Disease Control and Prevention, Baiyun District, No. 1 Qide Road, Guangzhou, 510440, China.
This study examines the impact of HIV post-exposure prophylaxis (PEP) on sexual behavior changes in men who have sex with men (MSM), aiming to assess a comprehensive HIV prevention strategy integrating biomedical and behavioral interventions to maximize PEP service effectiveness. From a Guangzhou MSM cohort, participants without prior PEP experience were included. The exposed group received PEP services during follow-up (June 2019-April 2022), while controls did not.
View Article and Find Full Text PDFBiol Res Nurs
January 2025
Department of Laboratory Medicine, Nanjing Pukou People's Hospital, Nanjing, China.
Background: The gap between 2-hour post-load plasma glucose (2 h PG) and fasting blood glucose (FBG) has been shown to be informative of the risk of developing prediabetes and diabetes. We aimed to examine the significance of the gap between 2 h PG and FBG in relation to all-cause or cardiovascular disease (CVD) mortality in normoglycemic adults.
Methods: 3611 normoglycemic participants from the 2005-2016 US National Health and Nutrition Examination Survey were included and dichotomized into the low (2 h PG ≤ FBG) and high post-load (2 h PG > FBG) groups.
Crim Behav Ment Health
January 2025
Department of Criminal Justice, Kutztown University, Kutztown, Pennsylvania, USA.
Background: The importation model holds that inmate behaviour is a function of behaviours and thought patterns offenders bring with them into prison from the community. It may also be that offenders export behaviours and thought patterns they develop or refine in prison when they return to the community.
Aims: The purpose of this study was to determine whether an increase in reactive criminal thinking in prisoners predicts recidivism following release.
J Intern Med
January 2025
Artificial Intelligence in Medicine (AIM) Program, Mass General Brigham, Harvard Medical School, Harvard Institutes of Medicine (HIM), Boston, Massachusetts, USA.
Background: Steatotic liver disease (SLD) is a potentially reversible condition but often goes unnoticed with the risk for end-stage liver disease.
Purpose: To opportunistically estimate SLD on lung screening chest computed tomography (CT) and investigate its prognostic value in heavy smokers participating in the National Lung Screening Trial (NLST).
Material And Methods: We used a deep learning model to segment the liver on non-contrast-enhanced chest CT scans of 19,774 NLST participants (age 61.
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