LOWER-EXTREMITY AMPUTATION - INCIDENCE, RISK-FACTORS, AND MORTALITY IN THE OKLAHOMA INDIAN DIABETES STUDY

Oklahoma Indians with NIDDM (n = 1012) underwent a baseline examinatio n in 1972-1980. The incidence of and risk factors for first lower-extr emity amputation were estimated. The mortality rates of amputees using data from 875 patients who had no previous history of amputation and who underwent follow-up examination between 1987 and 1991 are presente d. The mean age of the 875 patients was 51.6 +/- 10.8 yr, and the mean duration of diabetes was 6.6 +/- 6.1 yr. After a mean follow-up time of 9.9 +/- 4.3 yr, the incidence rate of first LEA among diabetic Okla homa Indians was 18.0/1000 person-yr. The incidence rate was two times higher in men than in women. In both sexes, significant risk factors (P < 0.05) were retinopathy and duration of diabetes. Fasting plasma g lucose, use of insulin, and systolic blood pressure were significant f or men only. For women, plasma cholesterol and diastolic blood pressur e were additional risk factors. Compared with the mortality rate of 33 .5/1000 person-yr among nonamputees, the rate among amputees was 55.5/ 1000 person-yr. The 5-yr survival rate after first amputation was 40.4 %. For the amputees, the most common causes of death were diabetes (37 .3%), cardiovascular disease (29.1%), and renal disease (7.3%). The in cidence and mortality rates in diabetic Oklahoma Indians were higher t han those reported in Pima Indians and other diabetic populations. To lower the incidence of lower-extremity amputation in this high-risk po pulation, preventive action through education, foot care programs, and early detection of lesions must be intensified.