title: [Reduction in follow-up period of a study using criteria supplemental to death].
abstract: This work concerns the estimation of the follow-up period reduction for patients involved in a survival study when an auxiliary event is also used as an endpoint. An estimation procedure has been proposed using a surrogate criterion as an addition to the main endpoint criterion. This procedure is a two-stage study and enables us to estimate the survival function by using both criteria simultaneously. With a model of disease progression including the surrogate criterion as well as the main endpoint, simple calculations assess the gain in time with the two-stage procedure by comparison with a one-stage procedure. This gain in time, expressed in terms of a reduction of the follow-up period, depends on the prevalence of the surrogate criterion and its impact on survival. In the last part of this paper we discuss the advantages and disadvantages of such a procedure in common practice.
authors.affiliation: INSERM U 194, CHU Pitié-Salpêtrière, Paris.
authors.forename: P
authors.initials: P
authors.lastname: Flandre
mesh_terms: D005500:Follow-Up Studies; D006801:Humans; D015233:Models, Statistical; D016019:Survival Analysis; D013997:Time Factors
vernacular_title: Réduction du temps de suivi d'une étude par l'utilisation d'un critère supplémentaire au décès.