Biomedical subjects

Edsel A Peña

Publications and source records attributed to Edsel A Peña.

4 recordsLinked to original sources

PubMed2005

Modelling intervention effects after cancer relapses.

This article addresses the problem of incorporating information regarding the effects of treatments or interventions into models for repeated cancer relapses. In contrast to many existing models, our approach permits the impact of interventions to differ after each relapse. We adopt the general model for recurrent events proposed by Peña and Hollander, in which the effect of interventions is represented by an effective age process acting on the baseline hazard rate function. To accommodate the situation of cancer relapse, we propose an effective age function that encodes three possible therapeutic responses: complete remission, partial remission, and null response. The proposed model also incorporates the effect of covariates, the impact of previous relapses, and heterogeneity among individuals. We use our model to analyse the times to relapse for 63 patients with a particular subtype of indolent lymphoma and compare the results to those obtained using existing methods.

Female↗

PubMed2005

A basis approach to goodness-of-fit testing in recurrent event models.

A class of tests for the hypothesis that the baseline hazard function in Cox's proportional hazards model and for a general recurrent event model belongs to a parametric family C identical with {lambda(0)(.; xi): xi in Xi} is proposed. Finite properties of the tests are examined via simulations, while asymptotic properties of the tests under a contiguous sequence of local alternatives are studied theoretically. An application of the tests to the general recurrent event model, which is an extended minimal repair model admitting covariates, is demonstrated. In addition, two real data sets are used to illustrate the applicability of the proposed tests.

Journal Article↗

PubMed2004

Nonparametric Methods in Reliability.

Probabilistic and statistical models for the occurrence of a recurrent event over time are described. These models have applicability in the reliability, engineering, biomedical and other areas where a series of events occurs for an experimental unit as time progresses. Nonparametric inference methods, in particular, the estimation of a relevant distribution function, are described.

Journal Article↗

PubMedDate not supplied

[Non-parametric estimation of survival function for recurrent events data].

Recurrent events when we deal with survival studies demand a different methodology from what is used in standard survival analysis. The main problem that we found when we make inference in these kind of studies is that the observations may not be independent. Thus, biased and inefficient estimators can be obtained if we do not take into account this fact. In the independent case, the interocurrence survival function can be estimated by the generalization of the limit product estimator (Peña et al. (2001)). However, if data are correlated, other models should be used such as frailty models or an estimator proposed by Wang and Chang (1999), that take into account the fact that interocurrence times were or not correlated. The aim of this paper has been the illustration of these approaches by using two real data sets.

Data Interpretation, Statistical↗