POLYCHOTOMOUS MULTIVARIATE MODELS FOR CORONARY HEART-DISEASE SIMULATION .5. THE IMPACT OF PHYSIOLOGICAL AGING

This is an extension of a series of papers dealing with certain models used in the simulation of coronary heart disease. The current study i nvestigates implications of including age as a risk factor in the mode ls discussed in the preceding papers. The effects of using age as a ri sk factor were investigated in two ways. In one of these, age is inter preted as age of entry into the study; it is similar to the other risk factors in that it is assumed to be constant throughout the study. In the other, age is interpreted as the actual age; thus it increases du ring the course of simulations. Two polychotomous, multivariate risk f unctions developed in previous studies, the logistic risk and the Neym an exponential risk, were used to explore the effects of including age as a risk factor. The estimated risk coefficient for age was found to be statistically significant for both functions. The model performanc e was evaluated by comparing the observational data with outcomes simu lated using Monte Carlo techniques. It was found that the logistic ris k function failed to describe the observations either with age as a co nstant or with aging during the simulations. The models including the Neyman exponential risk avoidance fit the data well. The evaluation of the results indicates that aging during the simulations is better tha n using only the age as the constant value at entry to the study.