Incidence of Lower-Extremity Amputation in American Indians

Abstract

OBJECTIVE -To define incidence and predictors of nontraumatic lower-extremity amputation (LEA) in a diverse cohort of American Indians with diabetes. RESEARCH DESIGN AND METHODS -The Strong HeartStudy is a study of cardiovascular disease and its risk factors in 13 American-Indian communities. Data on the presence/ absence of amputations were collected at each of three serial examinations (1989 -1992, 1993-1995, and 1997-1999) by direct examination of the lower extremity. The logistic regression model was used to quantify the relationship between risk of LEA and potential risk factors, including diabetes duration, HbA 1c , peripheral arterial disease, and renal function.RESULTS -Of the 1,974 individuals with diabetes and without prevalent LEA at baseline, 87 (4.4%) experienced an LEA during 8 years of follow-up, and a total of 157 anatomical sites were amputated among these individuals. Amputation of toes was most common, followed by belowthe-knee and above-the-knee amputations. Age-adjusted odds of LEA were higher among individuals with unfavorable combinations of risk factors, such as albuminuria and elevated HbA 1c . Multivariable modeling indicated that male sex, renal dysfunction, high ankle-brachial index, longer duration of diabetes, less than a high school education, increasing systolic blood pressure, and HbA 1c predicted LEA risk.CONCLUSIONS -The 8-year cumulative incidence of LEA in American Indians with diabetes is 4.4%, with marked differences in risk by sex, educational attainment, renal function, and glycemic control. Diabetes Care 27:1885-1891, 2004D ata from the baseline examination of the Strong Heart Study (SHS) show that lower-extremity amputation (LEA) due to diabetes was present in 3% of the cohort and 6.3% of individuals with diabetes (1), findings that are generally consistent with previous studies (2-4) in other American-Indian tribes.Rates of incident LEA have been reported for several American-Indian tribes (5-8). Previous studies have shown that hyperglycemia (5,6,9,10), duration of diabetes (5,6), male sex (2,5,6,10), and prevalent microvascular disease (5,6,10) contribute to LEA risk in American Indians.The purpose of this study is to define the incidence of first LEA due to diabetes in a diverse, population-based cohort of American Indians with diabetes. We hypothesized that among SHS participants with diabetes, increasing age, diabetes duration, glycemic control, smoking, peripheral arterial disease, renal dysfunction, and male sex would predict incident LEA and that combinations of risk factors, such as poor glycemic control and renal dysfunction, would interact to increase LEA risk. RESEARCH DESIGN AND METHODS -The SHS was initiated in 1988 to investigate cardiovascular disease and its risk factors in American Indians (11). The design, methods, and laboratory techniques of the SHS have been previously reported (12,13). The SHS cohort consists of 4,549 participants aged 45-74 years from 13 AmericanIndian communities in Oklahoma, the Dakotas, and Arizona who were seen at the basel...

Smoking increases the risk of diabetic foot amputation: A meta-analysis

“…A notable amount of literature exists on risk factors for amputation among patients with diabetes. A number of risk factors have been reported, including age (31,32), gender (33,34), ischemic heart disease (31), hypertension (31), peripheral artery disease (35), nephropathy (36), duration of diabetes (37) and hemoglobin A1C (38,39). However, there are inconsistencies among studies regarding smoking as a risk factor for diabetic foot amputation.…”

Falsely high ankle-brachial index predicts major amputation in critical limb ischemia

“…Very interestingly, this finding was independent of the presence of diabetes mellitus and renal insufficiency, factors known to be associated with both falsely high ABI values and risk of amputation. 2,4,12,20,21 A link between high ABI and poor outcome was found also in the Strong Heart Study, 17,18 which investigated a population with a high prevalence of diabetes mellitus. By contrast, results from the Atherosclerotic Risk in Communities Study 22 indicate that in general population with a low prevalence of PAD, those with a high ABI (Ͼ 1.3) do not suffer greater cardiovascular event rates than those with a normal ABI (0.9-1.3).…”

“…For instance, results from the Strong Heart Study indicate that high ABI values are associated with either mortality 17 or amputation. 18 The association between falsely high ABI values and clinical outcome has not been previously investigated in patients with CLI. Accordingly, we analyzed data from a prospectively collected database of patients with CLI to verify whether falsely high ABI values predict adverse clinical outcome.…”

Association between glycated haemoglobin and the risk of lower extremity amputation in patients with diabetes mellitus—review and meta-analysis

“…Description of studies Fourteen prospective studies [2,10,12,[20][21][22][23][32][33][34][35][36][37][38] involving 94,640 participants and 1,227 LEA cases were included. Details of study characteristics are provided ( Table 1).…”

“…Improved glycaemic control can potentially modify the risk of sensory neuropathy [5,50] and possibly the progression of peripheral arterial disease [8]. Other risk factors for LEA include increasing age and duration of diabetes, ethnicity, male sex, renal dysfunction, previous amputation or foot ulceration [34,51] and, in some studies, smoking [52,53].…”