PREVALENCE AND PREDICTION OF SILENT ISCHEMIA IN DIABETES-MELLITUS - APOPULATION-BASED STUDY

Objectives: The aim of the study was to estimate the prevalence of sil ent ischaemia in diabetic subjects in the population, to compare the p revalence of silent ischaemia in diabetics and non-diabetics and to at tempt to predict the presence of silent ischaemia in diabetic subjects . Methods: A random sample of 120 users of insulin and 120 users of or al hypoglycaemic agents aged 40-75 years living in the Danish municipa lity of Horsens were asked to participate in the study. Corresponding to the youngest half of the sample two non-diabetic controls were rand omly selected from the Central Population Register. ST-depression of h orizontal or descending character of at least 0.1 mV measured 80 ms af ter the J-point on either exercise ECG or Holter ECG was considered in dicative of myocardial ischaemia. Angina pectoris was considered prese nt if the Rose questionnaire was positive, or chest pain was registere d simultaneously with ECG evidence of ischaemia. Individuals with isch aemia, but without angina pectoris, were defined as persons with silen t ischaemia. Results: Seventy-four percent of the invited group were i ncluded. The observed prevalence of silent ischaemia in diabetics was 13.5% (95%Cl = 8.5-19.8%). No association was found between silent isc haemia and gender(P = 0.83) or diabetes type(P = 0.67). In the group o f diabetics who had controls, the prevalence was 11.4%, and among the controls the prevalence was 6.4% (OR = 1.87, one-sided P = 0.079). Sys tolic blood pressure was highly predictive of silent ischaemia in the diabetic subjects (P = 0.005), No predictive value could be shown for other variables, Conclusion: This is the first population-based study of silent ischaemia in diabetes. The prevalence of silent ischaemia in diabetic subjects was 13.5%. The frequency of silent ischaemia did no t differ significantly between diabetics and non-diabetics. Systolic b lood pressure was predictive of silent ischaemia in diabetes.