The Cox proportional hazards regression model has become the traditional choice for modeling survival data in medical studies. To introduce flexibility into the Cox model, several smoothing methods may be applied, and approaches based on splines are the most frequently considered in this context. To better understand the effects that each continuous covariate has on the outcome, results can be expressed in terms of splines-based hazard ratio (HR) curves, taking a specific covariate value as reference. Despite the potential advantages of using spline smoothing methods in survival analysis, there is currently no analytical method in the R software to choose the optimal degrees of freedom in multivariable Cox models (with two or more nonlinear covariate effects). This paper describes an R package, called , that allows the computation of pointwise estimates of the HRs—and their corresponding confidence limits—of continuous predictors introduced nonlinearly. In addition the package provides functions for choosing automatically the degrees of freedom in multivariable Cox models. The package is available from the R homepage. We illustrate the use of the key functions of the package using data from a study on breast cancer and data on acute coronary syndrome, from Galicia, Spain.

A recent paper in this journal by Chen and Chen has used computer simulations to examine a number of approaches to analysing sets of n-of-1 trials. We have examined such designs using a more theoretical approach based on considering the purpose of analysis and the structure as regards randomisation that the design uses. We show that different purposes require different analyses and that these in turn may produce quite different results. Our approach to incorporating the randomisation employed when the purpose is to test a null hypothesis of strict equality of the treatment makes use of Nelder’s theory of general balance. However, where the purpose is to make inferences about the effects for individual patients, we show that a mixed model is needed. There are strong parallels to the difference between fixed and random effects meta-analyses and these are discussed.

One major goal in clinical applications of multi-state models is the estimation of transition probabilities. The usual nonparametric estimator of the transition matrix for nonhomogeneous Markov processes is the Aalen-Johansen estimator (Aalen and Johansen 1978). However, two problems may arise from using this estimator: first, its standard error may be large in heavy censored scenarios; second, the estimator may be inconsistent if the process is non-Markovian. The development of the R package TPmsm has been motivated by several recent contributions that account for these estimation problems. Estimation and statistical inference for transition probabilities can be performed using TPmsm. The TPmsm package provides seven different approaches to three-state illnessdeath modeling. In two of these approaches the transition probabilities are estimated conditionally on current or past covariate measures. Two real data examples are included for illustration of software usage.

A pediculose é uma infecção parasitária comumente encontrada na comunidade escolar brasileira. A despeito das campanhas para controle do piolho de cabeça, as taxas de prevalência permanecem altas. Este trabalho apresenta o jogo educativo “Caça-Piolhos” como parte de uma sequência didática para informar, de forma lúdica, sobre a biologia do piolho e a prevenção da pediculose. Estudantes dos 4o e 5o anos do ensino fundamental de uma unidade escolar pública participaram de aulas expositivas dialogadas, oficinas além de participar do jogo “Caça-Piolhos”. Verificou-se que o jogo manteve um bom nível de engajamento dos estudantes, permitindo verificar o aprendizado dos conteúdos discutidos. Observou-se ainda a falta de interesse de alguns estudantes em função da idade e/ou dificuldades na leitura e compreensão das perguntas. Além de promover o aprendizado sobre a pediculose, este jogo poderia atuar como ferramenta na detecção de problemas de alfabetização se caso fosse incorporado à uma estratégia interdisciplinar envolvendo professores de Ciências e Português. Ao desenvolver ou utilizar jogos educativos é importante avaliar a qualidade destes produtos para assegurar que eles trazem benefícios à aprendizagem, justificando a sua utilização. Assim, estudos que desenvolvam métodos para avaliar a eficiência dos jogos educativos como metodologia ativa de ensino-aprendizagem são encorajados.

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