Electrocardiographic abnormalities predict deaths from cardiovascular disease and ischemic heart disease in Pima Indians with type 2 diabetes

Background The association between electrocardiographic (ECG) abnormalities and deaths from cardiovascular diseases (CVD) and ischemic heart disease (IHD) has been reported in the general population, but there is little information regarding persons with type 2 diabetes. Methods Minor and major ECG abnormalities were identified and classified according to the Minnesota Code in a longitudinal study of 1605 Pima Indians aged ≥35 years with type 2 diabetes. Underlying causes of death were determined by review of all available clinical records, autopsy reports, medical examinersʹ findings, and death certificates. Results During a median follow-up of 14.1 years (range 0.1 to 33.8 years), there were 190 CVD deaths, 135 (71.1%) of which were attributable to IHD. The age-adjusted CVD death rates in men with none, minor, and major ischemic ECG abnormalities were 7.3, 12.2 and 27.8, and in women, 4.3, 4.8 and 12.5 per 1000 person-years, respectively. After adjustment for other co-variables in a multiple proportional hazards model, subjects with minor and major ischemic abnormalities on ECG had 1.22 (95% CI, 0.76-1.97) and 1.83 (95% CI, 1.21-2.76) times the CVD death rate, and 1.32 (95% CI, 0.70-2.50) and 2.12 (95% CI, 1.26-3.57) times the IHD death rate of those with no ischemic ECG abnormalities, respectively. Conclusions The CVD and IHD death rates were higher in men and in subjects with major ischemic ECG abnormalities. Major ischemic abnormalities on ECG predicted death after accounting for other cardiovascular risk factors, including proteinuria.