Flexible longitudinal linear mixed models for multiple censored responses data

Autor(es)

Lachos, Victor H. ^[1] ; Matos, Larissa A. ^[2] ; Castro, Luis M. ^[3] ; Chen, Ming-Hui ^[1]

Afiliação do(s) autor(es)

^[1] Univ Connecticut, Dept Stat, 215 Glenbrook Rd, U-4120, Storrs, CT 06269 - USA

^[2] Univ Estadual Campinas, Dept Estat, Campinas, SP - Brazil

^[3] Pontificia Univ Catolica Chile, Dept Estadist, Santiago - Chile

• Tipo de documento: Artigo Científico
• Fonte: STATISTICS IN MEDICINE; v. 38, n. 6, p. 1074-1102, MAR 15 2019.
• Citações Web of Science: 0

Resumo

In biomedical studies and clinical trials, repeated measures are often subject to some upper and/or lower limits of detection. Hence, the responses are either left or right censored. A complication arises when more than one series of responses is repeatedly collected on each subject at irregular intervals over a period of time and the data exhibit tails heavier than the normal distribution. The multivariate censored linear mixed effect (MLMEC) model is a frequently used tool for a joint analysis of more than one series of longitudinal data. In this context, we develop a robust generalization of the MLMEC based on the scale mixtures of normal distributions. To take into account the autocorrelation existing among irregularly observed measures, a damped exponential correlation structure is considered. For this complex longitudinal structure, we propose an exact estimation procedure to obtain the maximum-likelihood estimates of the fixed effects and variance components using a stochastic approximation of the EM algorithm. This approach allows us to estimate the parameters of interest easily and quickly as well as to obtain the standard errors of the fixed effects, the predictions of unobservable values of the responses, and the log-likelihood function as a byproduct. The proposed method is applied to analyze a set of AIDS data and is examined via a simulation study. (AU)

• Processo FAPESP: 18/05013-7 - Modelos semi-paramétricos de efeitos mistos com respostas múltiplas censuradas sob a classe de distribuições misturas de escala normal
• Beneficiário: Larissa Avila Matos
• Modalidade de apoio: Auxílio à Pesquisa - Pesquisador Visitante - Internacional
• Processo FAPESP: 16/05420-6 - Modelos não lineares para respostas censuradas múltiplas usando distribuições de caudas pesadas
• Beneficiário: Larissa Avila Matos
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado