Abstract

LOPERA-GOMEZ, CARLOS MARIO; JARAMILLO-ELORZA, MARIO CÉSAR  and  ACOSTA-BAENA, NATALIA. ¿ When does Alzheimer's Disease Begin? Kaplan-Meier versus Turnbull: An Application to Arbitrary Censoring Data. Rev.Colomb.Estad. [online]. 2012, vol.35, n.spe2, pp.239-254. ISSN 0120-1751.

Most of the survival analysis are based on exact failure times and right censored observations, using methods widely known as the Kaplan-Meier (KM). To estimate the onset age of familial Alzheimers Disease (AD) when the censor times are arbitrary (right, left or interval censor), what is the change in clinical outcomes, using the KM method with data imputation compared with procedure proposed by Turnbull for this kind of data? Turnbulls method was compared with KM method in a simulation study and an application with real data. KM method was based on data imputation through the midpoint of the interval (MP) and the right side of the interval (RS), considering several sample sizes and different times between visits. In all simulation scenarios estimated functions using data imputation differ significantly from the actual simulated survival function S(t). The estimated onset age of AD through data imputation methods has relevant clinical implications that would affect decision-making in initiating preventive therapy. Turnbulls method has fewer bias when was compared with KM with imputation to perform a survival analysis with arbitrary censure data.

Keywords : Age of onset; Familial Alzheimer's disease; Interval censoring; Survival analysis.

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