11,988 research outputs found
Dichotomizing biomarkers for failure time outcome: from classification probabilities to predictive values based methods
No full textCut-Point Finding Methods For Continuous Biomarkers In The Presence Of Binary And Censored Failure Time Outcome
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Single-Incision Versus Standard Multiple-Incision Laparoscopic Cholecystectomy: A Meta-analysis of Experimental and Observational Studies
No full textThe role of hepatitis C and B virus infection as risk factors for severe liver complications following allogeneic BMT: a prospective study by the infectious disease working party of the European Blood and Marrow Group.
No full textI.F.3.26
OUTCOME OF CHILDREN (NON-INFANT) WITH T(4;11) POSITIVE ACUTE LYMPHOBLASTIC LEUKEMIA TREATED WITH AIEOP-LLA 2000-R2006 PROTOCOLS
No full textSurvival probabilities with time-dependent treatment indicator: quantities and non-parametric estimators
No full textThe 'landmark' and 'Simon and Makuch' non-parametric estimators of the survival function are commonly used to contrast the survival experience of time-dependent treatment groups in applications such as stem cell transplant versus chemotherapy in leukemia. However, the theoretical survival functions corresponding to the second approach were not clearly defined in the literature, and the use of the 'Simon and Makuch' estimator was criticized in the biostatistical community. Here, we review the 'landmark' approach, showing that it focuses on the average survival of patients conditional on being failure free and on the treatment status assessed at the landmark time. We argue that the 'Simon and Makuch' approach represents counterfactual survival probabilities where treatment status is forced to be fixed: the patient is thought as under chemotherapy without possibility to switch treatment or as under transplant since the beginning of the follow-up. We argue that the 'Simon and Makuch' estimator leads to valid estimates only under the Markov assumption, which is however less likely to occur in practical applications. This motivates the development of a novel approach based on time rescaling, which leads to suitable estimates of the counterfactual probabilities in a semi-Markov process. The method is also extended to deal with a fixed landmark time of interest
Risultati del protocollo AIEOP-LLA 95 per il trattamento della leucemia linfoblastica acuta (LLA) dellâ€TMetà pediatrica.
No full textThe role of hepatitis C and B virus infections as risk factors for severe liver complications following allogeneic BMT: a prospective study by the Infectious Disease Working Party of the European Blood and Marrow Transplantation Group.
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