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DTSTAMP:20251219T022908Z
DESCRIPTION:Michal Abrahamowicz\, PhD\n\nDistinguished James 9I制作厂免费 Profess
 or\n	Department of Epidemiology\, Biostatistics and Occupational Health | M
 cGill University\n\nWHEN: Wednesday\, Jan 7\, 2026\, from 3:30 to 4:30 p.m
 .\n	WHERE: Hybrid | 2001 9I制作厂免费 College Avenue\, Rm 1140\; Zoom\n	NOTE:聽Mich
 al Abrahamowicz will be presenting in-person at SPGH聽\n\nAbstract\n\nWeigh
 ted Cumulative Exposure (WCE) methodology has been developed to allow for 
 flexible modelling of the cumulative effects of time-varying exposures (TV
 E) [1]. In time-to-event analyses\, the joint impact of past TVE values\, 
 for person i\, is quantified as: WCE饾憱鈦� (饾憿) = 鈭戰潙� 饾懁 鈦�(饾憿鈭掟潙�)[鈦潙嬸潙栤仭 (饾憽)]\, where
  u is the current time when the hazard is assessed\, and 饾憢饾憱鈦� (饾憽)\, 饾憽 鈮� 饾憿\,
  represent TVE values observed at earlier times. The essential component o
 f the model is the weight function 饾懁 鈦�(饾憿鈭掟潙�) which is estimated using cubic
  splines and indicates how the importance of the TVE value observed at tim
 e t\, for the hazard at time饾憿 鈦�(饾憿鈭掟潙�)\, varies with time 鈦�(饾憿鈭掟潙�) since it wa
 s measured [1]. The WCE modeling\, originally developed for Cox proportion
 al hazards analyses [1]\, has been extended to competing risks\, marginal 
 structural models and mixed effects linear modeling of longitudinal change
 s in a quantitative outcome (see e.g. a recent overview in [2]). It has be
 en recognized as one of the most useful methods for assessing TVE effects 
 in pharmaco-epidemiology [3].\n	\n	The talk will present an overview of the 
 phases of the development and establishing of the WCE methodology\, includ
 ing its consecutive extensions\, and validation in simulations. I will dis
 cuss how and to what extent our work on the WCE modelling followed the pha
 ses identified by Heinze et al in their recent paper on the phases of meth
 odological research in biostatistics [4]. In addition\, further phases suc
 h as (a) establishing the need for the new methodological development\, (b
 ) proof-of-the-concept phase\, and (c) refining the estimation and statist
 ical inference\, will be outlined.\n\nIn this context\, three important as
 pects of real-world applications will be briefly discussed. (i) Firstly\, 
 I will emphasize the need to incorporate substantive knowledge\, and the r
 elated challenges. (ii) Secondly\, I will illustrate the ability of the WC
 E analyses to provide new insights into\, and generate new hypotheses abou
 t\, the underlying biological processes linking the exposure with the outc
 omes. (iii) I will also outline how some real-world results stimulated new
  methodological developments\, necessary to address additional analytical 
 challenges.\n\nFinally\, the need of future research to carry out the addi
 tional phase\, focusing on neutral simulations to further validate the WCE
  methodology and compare it with the existing alternative approaches\, as 
 recommended in [4]\, will be briefly presented\,\n\n[1] Sylvestre M-P & Ab
 rahamowicz M. Flexible modeling of the cumulative effects of\n	time depende
 nt exposures on the hazard.聽Statistics in Medicine.聽2009 Nov\;28(27):3437-
 3453.\n	[2] Abrahamowicz M.聽Assessing cumulative effects of medication use:
  new insights\n	and new challenges.聽Invited Commentary.聽Pharmacoepidemiolog
 y & Drug Safety.\n	2024 Jan\;33(1):e5746. doi: 10.1002/pds.5746.\n	[3] Pazza
 gli L\, Linder M\, et al. Methods for time-varying exposure related proble
 ms in\n	pharmacoepidemiology: An overview.聽Pharmacoepidemiology & Drug Safe
 ty聽2018\;27:148-160.\n	[4] Heinze G.\, Boulesteix AL\, Kammer M.\, Morris T
 P\, White I. Phases of methodological research in biostatistics.聽Biometric
 al Journal.聽2024.\n\nSpeaker Bio\n\nMichal Abrahamowicz is a Distinguished
  James 9I制作厂免费 Professor of Biostatistics at 9I制作厂免费. He develops
  new\, flexible statistical methodology for survival analyses\, with focus
  on time-varying exposures and effects. He also explores\, and attempts to
  correct for\, different biases in epidemiological studies and promotes cr
 eative applications of statistical simulations. He is a co-founder and the
  co-chair of the international STRATOS initiative for improving the analys
 es of observational studies. He is a Honorary Lifetime member of the Inter
 national Society for Clinical Biostatistics.\n
DTSTART:20260107T203000Z
DTEND:20260107T213000Z
SUMMARY:Phases of Development of the Weighted Cumulative Exposure Modeling
URL:/epi-biostat-occh/channels/event/phases-developmen
 t-weighted-cumulative-exposure-modeling-369614
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