ABSTRACT
The purpose of this paper was to introduce the methods of the "layered person-time data" rate ratio analysis and the SAS implementation. The specific contents included the following four aspects： ① the point estimation and the confidence interval estimation of the layer i rate ratio in the stratified person-time data； ② the homogeneity test of the rate ratios among the different layers； ③ the point estimation and the confidence interval estimation of the common rate ratio； ④ the linear trend test of the incidence density in the stratified person-time data. Through two examples， it showed the statistical calculation process based on the SAS software to realize the aforementioned four kinds of the analysis contents， including providing the SAS program code， the explanation of the SAS output results， and giving the statistical and professional conclusions.
ABSTRACT
The purpose of this paper was to introduce the independence test and the SAS implementation for the "unstratified person-time data" and the "stratified person-time data". In "person-time data"， the sample size in each level of the treatment factor was expressed as "person-years". Furthermore， it was necessary to use the "incidence density" to replace the "incidence rate" in the usual qualitative data analysis. The paper introduced the concrete approaches of comparing the "incidence density" of the "unstratified person-time data" and the "stratified person-time data" in detail， and demonstrated the whole process of using SAS software to realize the calculation through two examples， including the SAS program code， the SAS output results， the results explanation and the conclusion statement.
ABSTRACT
It is clinically important to evaluate the safety and efficacy of Kampo prescriptions in long-term treatment cases. One practical method for this issue is to evaluate the incidence rates of events in long-term treatment cases. This paper gives an outline of this method and describes a statistical approach for evaluating the incidence rates of events.