Mortality, causes of death and associated risk factors in a cohort of diabetic patients after lower-extremity amputation: A 6.5-year follow-up study in Taiwan

Background: To determine the mortality, causes of death and associated risk factors in Taiwanese diabetic patients after lower-extremity amputation (LEA). Methods: A total of 358 diabetic patients (191 men and 167 women, aged 66.6 ± 10.3 years) after LEA from the Taiwanese cohort of 778 cases previously recruited in the multinational Global Lower Extremity Amputation Study were followed. Risk factors included age, sex, smoking, body mass index (BMI), hypertension, systolic (SBP) and diastolic blood pressure (DBP), and LEA level. Mortality was ascertained from the National Death Registry. Results: With a follow-up period of up to 6.5 (median: 4.0) years and 1239.17 patient-years, 214 patients died. Crude mortality rate was 172.7 per 1000 patient-years and median survival time 4.1 years. The underlying cause of death was recorded as diabetes mellitus in 57.9% of those who died and none to disease of arteries, arterioles and capillaries. After adjustment for age and sex, smoking, SBP as a continuous variable, SBP ≥140 mmHg and BMI <18.5 kg/m² (underweight) were predictors for mortality with respective odds ratios (95% confidence intervals) of 1.580 (1.030-2.425), 1.011 (1.000-1.022), 1.363 (1.007-1.845) and 1.889 (1.203-2.968); but hypertension, DBP as a continuous variable and DBP ≥90 mmHg, BMI as a continuous variable and LEA level were not. Conclusions: Mortality after LEA in Taiwanese diabetic patients is high. The most common cause of death was recorded as diabetes mellitus. After adjustment for age and sex, smoking, SBP and underweight are predictive for mortality; while LEA level is not.