patients' data (NAFLD risk factors & fibrosis stages)

The dataset describes 150 patients with the following demographic characteristics : sex, age, HOMA-IR , systolic and diastolic blood pressure , and LDL-Cholesterol . These patients were followed for 28 years . The characteristics are the mean of the following measurement each year. In each year a liver biopsy was taken to record the stage of fibrosis and then the count of transition among stages is recorded in the columns called ( lambda ij) where the i,j represents the stages where the patients move between them . In other word , for each patient , there is a column for the transition count this patient had made from stage 0 to stage 1 , then there is another column for the transition counts he made from stage 1 to stage 2 in this follow up 28 years , and so on , that is to mean there are 9 columns for the count of each transition for each patient as there are 9 transitions that could be made : from 0 to 1 , from 1 to 2 , from 2 to 3 , from 3 to 4 , from 1 to 0 , from 2 to 1 , from 3 to 2 , from 2 to 0 and from 3 to 1 . these transition counts are the dependent or the response variable , while the demographic characteristics are the predictors or the independent variables . Using Poisson regression model is used to relate these counts with the risk factors for NAFLD .