Rough classification of patients after highly selective vagotomy for duodenal ulcer

The concept of “rough” sets is used to approximate the analysis of an information system describing 77 patients with duodenal ulcer treated by highly selective vagotomy (HSV). The patients are described by 11 attributes. The attributes concern sex, age, duration of disease, complication of duodenal ulcer and various factors of gastric secretion. Two values of sex and age are distinguished, five values of complications and three or four values of secretion attributes, according to norms proposed in this paper. For each patient, the result of treatment by HSV is expressed in the Visick grading which corresponds to four classes. Using the method of rough classification it is shown that the given norms ensure a good classification of patients. Afterwards, some minimum sets of attributes significant for high-quality classification are obtained. Upon analysis of values taken by attributes belonging to these sets a “model” of patients in each class is constructed. This model gives indications for treatment by HSV.