Excess accumulation of risk factors in ischemic heart disease.

Though multiple risk factors are commonly observed in patients with ischemic heart disease and associated with an increased risk of developing IHD, it has not yet been proven that risk factors actually occur in combination more frequently than by chance alone. We tested the hypothesis that if some risk factors occur in combination, the actual incidences will be higher than the predicted ones which were calculated on the assumption that each risk factor occurs independently and in combination as a result of coincidence. One hundred consecutive patients were included in this study. All had significant stenosis or occlusion of a coronary artery. The ages ranged from 50 to 69 years and only males were studied. From the incidences of the well-established risk factors in IHD: hypertension, impaired glucose tolerance or diabetes mellitus, hypertriglyceridemia, obesity and hypercholesterolemia, we determined the actual incidences of combinations of risk factors and compared these with the predicted incidences, which were the probability calculated from each risk factor. Some of the combinations of 2 to 4 risk factors were found significantly more often than the predicted ones. Though not significant, the reverse was the case in the actual incidence of patients having no risk factors. Some combinations of well-known risk factors were found more often than the predicted risk factors from the probability and showed a tendency to cluster in coronary artery disease patients. Some linking factor must be involved in this type of occurrence of risk factors.