Long-term survival models applied to a study of the return behavior of voluntary blood donors

Adriana de FÁtima LOURENÇON[1]

Edson Zangiacomi MARTINEZ1

Josmar MAZUCHELI[2]

Oranice FERREIRA[3]

§                     ABSTRACT: Strategies to ensure safe supplies of blood in hemotherapy and transfusion services, stimulating the return of voluntary donors, depend on the knowledge of the return behavior of blood donors. In the present article, we use long-term survival models for modeling the time between the first donation of blood and the next return, considering the distributions Weibull, log-normal, log-logistic and generalized gamma. We consider that the parameter of scale and the proportion of individuals that do not return to new donations are dependents of a vector of covariates. We observe that the long-term survival models, especially the model based on the generalized gamma extended distribution, adequately describe the behavior of return of the blood donor.

§                     KEYWORDS: Survival analysis; long-term survival model; generalized gamma distribution; blood donors; biostatistics.



[1]Departamento de Medicina Social, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo. E‑mail: adlourencon@yahoo.com.br / edson@fmrp.usp.br

[2]Departamento de Matemática, Centro de Ciências Exatas, Universidade Estadual de Maringá – UEM, Maringá, PR, Brasil

[3] Centro Regional de Hemoterapia do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto (Hemocentro), Universidade de São Paulo – FMRP/USP, Ribeirão Preto, SP, Brasil