Lower-Extremity Amputation: Incidence, Risk Factors, and Mortality in the Oklahoma Indian Diabetes Study

  1. Elisa T Lee
  1. Department of Biology, Harvard University Cambridge, Massachusetts Center for Epidemiologic Research, Department of Medicine, and Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center Oklahoma City, Oklahoma Department of Surgery, Duke University Medical School Durham, North Carolina
  1. Address correspondence and reprint requests to Dr. Elisa T. Lee, Center for Epidemiologic Research, College of Public Health, University of Oklahoma Health Sciences Center, P.O. Box 26901, Oklahoma City, OK 73190.

Abstract

Oklahoma Indians with NIDDM (n = 1012) underwent a baseline examination in 1972–1980. The incidence of and risk factors for first lower-extremity 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 presented. 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 Oklahoma 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 glucose, use of insulin, and systolic blood pressure were significant for men only. For women, plasma cholesterol and diastolic blood pressure 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 incidence and mortality rates in diabetic Oklahoma Indians were higher than those reported in Pima Indians and other diabetic populations. To lower the incidence of lower-extremity amputation in this high-risk population, preventive action through education, foot care programs, and early detection of lesions must be intensified.

  • Received August 28, 1992.
  • Revision received January 28, 1993.
  • Accepted January 28, 1993.
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