10-YEAR CARDIOVASCULAR MORTALITY IN RELATION TO RISK-FACTORS AND ABNORMALITIES IN LIPOPROTEIN COMPOSITION IN TYPE-2 (NON-INSULIN-DEPENDENT)DIABETIC AND NONDIABETIC SUBJECTS

The purpose of the present study was to examine 10-year cardiovascular morbidity and mortality in patients with newly-diagnosed Type 2 (non- insulin-dependent) diabetes mellitus and non-diabetic control subjects and to evaluate the effects of general risk factors, plasma insulin, urinary albumin excretion, lipoprotein abnormalities characteristic of Type 2 diabetes and the degree of hyperglycaemia in diabetic patients on cardiovascular mortality. Furthermore, the extent to which the abo ve-mentioned factors could contribute to the excessive cardiovascular mortality observed in diabetic patients was examined. In the years 197 9-1981, altogether 133 (70 men, 63 women) newly-diagnosed patients wit h Type 2 diabetes and 144 (62 men, 82 women) non-diabetic control subj ects aged 45-64 years were studied. Both groups were re-examined in th e years 1985-1986 and 1991-1992. The impact of different factors on ca rdiovascular mortality was examined by univariate analyses after adjus tment for age and sex and by multiple logistic regression analyses. Th e age-standardized total and cardiovascular mortality rates were subst antially higher in diabetic men (17.8 and 15.0%, total and cardiovascu lar mortality, respectively p = 0.06 and NS) and women (18.5 and 16.6% , p < 0.01 for both) than in non-diabetic control men (5.2% both total and cardiovascular mortality) and women (4.2 and 2.2%). Cardiovascula r mortality was not related to the treatment modality (diet, oral drug s, insulin) at 5 years from diagnosis. Use of diuretics, beta-blocking agents or their combination at baseline did not make a significant co ntribution to cardiovascular mortality either. In multiple logistic re gression analysis on diabetic patients, age, LDL triglycerides, smokin g, blood glucose and ischaemic ECG at baseline had independent associa tions with cardiovascular mortality. Interestingly, urinary albumin ex cretion rate measured at 5-year examination also predicted 10-year car diovascular mortality after adjustment for the effects of major risk f actors including lipoprotein abnormalities, but its predictive power r educed to a non-significant level when the effect of plasma glucose wa s taken into account. The relative risk of cardiovascular mortality as sociated with diabetes was 8.2 after allowing for age alone, but it de clined to 3.7 when all contributing factors from the baseline examinat ion (except blood glucose) were taken into account. In conclusion, the present results indicate that LDL triglycerides and/or other changes in lipoprotein composition characteristic of Type 2 diabetes and manif esting as elevated serum triglycerides are atherogenic and they strong ly predict increased cardiovascular mortality. Furthermore, it is hypo thesized that the consequences of long-term hyperglycaemia could expla in a large proportion of the remaining excessive cardiovascular mortal ity risk among Type 2 diabetic patients.