Estimating the stenosis probabilities in arteriosclerosis obliterans using generalized estimating equations

For each of 211 arteriosclerosis obliterans patients, the degree of stenosis of arteries at four sites were examined at Hiroshima University Hospital to analyse the relationship between the degree of stenosis and age, sex and site. The generalized estimating equations using a proportional odds model for the stenosis probability with exchangeable correlation was applied to this clustered, ordered polytomous data. Since the correlations between the responses were quite small, we could apply the independence estimating equations. The best mean model selected by Akaike information criterion suggested that age dependency of the stenosis probability was not observed in the central sites but was observed in the peripheral sites, and symmetry of the risk of stenosis was seen in the left and right sites. Details of the analysis will be described.