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Revista Panamericana de Salud Pública

On-line version ISSN 1680-5348Print version ISSN 1020-4989

Rev Panam Salud Publica vol.28 n.3 Washington Sep. 2010

http://dx.doi.org/10.1590/S1020-49892010000900012 

INVESTIGACIÓN ORIGINAL ORIGINAL RESEARCH

 

Ethnic and health correlates of diabetes-related amputations at the Texas-Mexico border

 

Correlatos étnicos y de salud de las amputaciones relacionadas con la diabetes en la frontera entre Texas y México

 

 

Nelda MierI; Marcia OryII; Dongling ZhanIII; Edna VillarrealI; Maria AlenI; Jane BolinII

IDepartment of Social and Behavioral Health, Texas A&M School of Rural Public Health, McAllen, Texas, United States of America. Send correspondence to Nelda Mier, nmier@srph.tamhsc.edu
IIDepartment of Social and Behavioral Health, Texas A&M School of Rural Public Health, College Station, Texas, United States of America
IIIDepartment of Statistics, Texas A&M University, College Station, Texas, United States of America

 

 


ABSTRACT

OBJECTIVE: To examine the association between diabetes-related lower-extremity amputation (LEA) and ethnicity, age, source of payment, geographic location, diabetes severity, and health condition in adults with diabetes mellitus type 2 living in border and non-border counties in Texas, United States of America, and to assess intra–border region geographic differences in post-LEA treatment.
METHODS: This correlational study was based on secondary data from the 2003 Texas Inpatient Hospital Discharge Data. The sample consisted of individuals 45 years of age and older with type 2 diabetes who had undergone a nontraumatic LEA (n = 5 865). Descriptive statistics and logistic regression analyses were applied.
RESULTS: The following characteristics were predictors of LEA: being Hispanic or African American, male, > 55 years old, and a Medicare or Medicaid user, and living in a border county. Persons with moderate diabetes and those who suffered from cardiovascular disease or stroke also had higher odds of undergoing an LEA. Post-LEA occupational therapy was significantly less prevalent among border residents (9.5%) than non-border residents (15.3%) (P < 0.001).
CONCLUSION: Understanding the factors that influence diabetes-related LEA may lead to early detection and effective treatment of this disabling consequence of diabetes along the U.S.-Mexico border.

Key words: Amputation; border health; diabetes mellitus, type 2; minority health; Mexico; Texas; United States.


RESUMEN

OBJETIVO: Analizar la asociación entre las amputaciones de extremidades inferiores (AEI) relacionadas con la diabetes y el grupo étnico, la edad, la procedencia del pago, la ubicación geográfica, la gravedad de la diabetes y el estado de salud de los adultos que padecen diabetes tipo 2 residentes en los condados fronterizos y no fronterizos de Texas (Estados Unidos de América), y evaluar la diferencias geográficas dentro de la zona fronteriza en cuanto al tratamiento posterior a la amputación.
MÉTODOS: Este estudio correlacional se basó en datos secundarios procedentes de la información de egreso de pacientes hospitalizados en Texas durante el año 2003. La muestra estuvo integrada por personas de 45 años o mayores con diabetes tipo 2, que habían sido sometidas a la amputación no traumática de una extremidad inferior (n = 5 865). Se aplicaron estadística descriptiva y análisis de regresión logística.
RESULTADOS: Las siguientes características constituyeron factores predictivos de AEI: ser hispano o afroestadounidense, hombre, de 55 años o mayor, beneficiario de Medicare o Medicaid, y residente en un condado fronterizo. Las personas con diabetes moderada que padecían enfermedades cardiovasculares o habían sufrido un accidente cerebrovascular también tenían una mayor probabilidad de ser sometidas a una AEI. La terapia ocupacional posterior a la amputación fue significativamente menos prevalente entre los residentes fronterizos (9,5%) que entre los no fronterizos (15,3%) (P < 0,001).
CONCLUSIONES: La comprensión de los factores que influyen en las AEI relacionadas con la diabetes puede conducir a la detección temprana y el tratamiento eficaz de esta secuela discapacitante en la zona fronteriza entre los Estados Unidos y México.

Palavras chave: Amputación; salud fronteriza; diabetes mellitus tipo 2; salud de minorías; México; Texas; Estados Unidos.


 

 

As observed by the World Health Organization (WHO), diabetes-related amputations cause unnecessary disability and mortality (1). Although up to 80% of all diabetes-related lower-extremity amputations (LEAs) can be prevented with self-management health behaviors (1), this disabling condition is one of the most common causes of hospitalization for individuals with diabetes, and has great social, medical, and economic costs worldwide (1–5). LEA in persons with diabetes is a predictor of reduced quality of life (6), repeat amputation at five-year follow- up (7), and seven-year mortality (8).

Ethnic minority groups in the United States of America have significantly higher risk and prevalence of amputations, as well as higher associated mortality rates, than their non-Hispanic white counterparts (9–12). Lavery et al. identified a much higher prevalence of diabetes-related amputations in Hispanics (82.7%) versus African Americans (61.6%) and non-Hispanic whites (56.8%) in the United States (13).

This diabetes disparity is even more salient in the U.S.-Mexico border region, where U.S. border states have the highest Hispanic concentration in their populations (14). The Pan American Health Organization (PAHO) has warned that diabetes is rising in the region, and significant efforts are under way to address this public health problem, which is of great concern in the Americas (15). Since 2001, PAHO has been coordinating a binational (United States-Mexico) initiative that has determined border diabetes prevalence rates and is working on developing prevention programs and activities in the border region (16). The diabetes age- adjusted death rate for Hispanics living in U.S. border counties (46.7 per 100 000 population) is three times higher than the rate for non-Hispanic whites living at the border (16.3 per 100 000 population) (17). Among all border residents, almost 16% suffer from type 2 diabetes, a higher rate than the national rate in both Mexico (14.9%) and the United States (13.9%) (15, 18). A study published in 2006 showed that in Texas the adjusted rate of diabetes-related LEAs is significantly higher for border county residents (53.6 per 10 000) versus non-border residents (39.9 per 10 000) (19).

A key strategy in the planning process of diabetes prevention and control programs is the identification of predictors that influence the disease and its complications. Although previous studies have described rates of diabetes mortality and prevalence as well as amputation in the U.S.-Mexico border region, there is a paucity of data on risk factors for diabetes-related LEAs. Loss of a limb is a diabetes complication that leads to disability and death yet in most cases could have been prevented with self-care interventions (1, 20). Identification of these risk factors could help policy makers and health professionals design and implement more effective foot care interventions for groups most at risk of suffering from this disabling diabetes complication. The purpose of this study was to examine the association between LEAs and ethnicity, age, source of payment, geographic location, diabetes severity, and health condition in adults with type 2 diabetes living in border and non-border counties in Texas, and to assess intra–border region geographic differences in post-LEA treatment.

 

MATERIALS AND METHODS

This correlational study was based on data from the 2003 Texas Inpatient Hospital Discharge Data (TIHDD). The TIHDD dataset contains demographic, geographic, medical, and source-of- payment data on hospital inpatient discharges from approximately 95% of state-licensed hospitals in Texas, coded by International Classification of Diseases, Ninth Revision, Clinical Modification (IDC-9-CM) and diagnosis-related group (DRG). Individuals identified for this study were 45 years of age and older, had type 2 diabetes (IDC-9-CM codes 250.00 and 250.02), and had undergone a nontraumatic LEA (IDC-9-CM codes 84.11–84.19) during 2003. Previous studies show that the prevalence of diabetes-related LEAs is significantly higher for individuals 45 years of age and older compared to younger individuals (12, 13, 19).

The study also examined relevant variables that influence diabetes-related LEAs, according to the literature, which is based mainly on non-Hispanic white samples (21–26). These variables included sex; age group, based on U.S. Centers for Disease Control and Prevention (CDC) categories (45–55, 56–64, and > 65 years) (27); ethnic group (Hispanic, African American, non-Hispanic white, and other); source of payment for health care services (state government–funded programs, federal government–funded programs such as Medicare and Medicaid, employer-provided private insurance, and uninsured/self-pay patients); and geographic location (Texas border counties versus non-border counties). Border counties were defined as the 32 counties in Texas within 100 km of the U.S.-Mexico border. Income information was not available. Health variables included health condition factors and severity of diabetes (minor, moderate, and severe). Health condition factors included hypertension (IDC-9-CM codes 401–405); cardiovascular disease (CVD) (IDC-9-CM codes 410–414, 427, and 428); stroke (IDC-9-CM codes 431–434, 436, and 437); chronic obstructive pulmonary disease (COPD) (IDC-9-CM codes 491, 492, and 496); depression (IDC-9-CM codes 296 and 311); and renal disease (IDC-9-CM codes 580–586, 588, 589, and 593). The severity-of-illness variable in the TIHDD dataset were coded under four categories: minor, moderate, major, and extreme. Because very few individual in the study sample (2%) were classified as "extreme," the categories "major" and "extreme" were combined into one global category called "severe." The TIHDD dataset does not provide information about how the reporting hospitals measured severity of illness. Summary statistics were calculated to describe the sample in terms of demographic and health conditions. Demographic characteristics and other indicators between border and non-border groups were compared using either the Pearson chi-square test or the Mann-Whitney U test, as appropriate. These statistical tests were used due to the non-normality of the data. Logistic regression analyses (unadjusted univariate and adjusted multivariate logistic regression) were used to test the association between the independent variables and LEA. Logistic regression analysis is presented as odds ratios (ORs) and 95% confidence intervals (CIs). The analysis was performed using SPSS for Windows, version 13.0 (SPSS Inc., Chicago, Ill., USA) (28). A P value < 0.05 was considered significant for all statistical tests conducted.

 

RESULTS

Out of the 204 776 patients listed in the TIHDD, a total of 5 865 persons 45 years of age and older had undergone a diabetes-related LEA. The number of persons with an LEA in the border area was 1 037 versus 4 828 in non-border counties. As shown in Table 1, significant differences were found between border and non-border individuals who had undergone an LEA by age (P = 0.001), ethnicity (P < 0.001), and source of payment (P < 0.001), but not by sex.

 

 

There were three times more Hispanics undergoing an LEA in border counties versus non-border areas (P < 0.001). In contrast, a statistically significant higher proportion of non-Hispanic whites and African Americans that had undergone an LEA resided in non-border counties versus border counties. There was also a higher proportion of older persons (> 65 years) with LEAs at the border area (72.71%) versus the same age group in non-border counties (66.76%) (P = 0.001).

Compared to persons with LEAs in non-border counties, two times more individuals at the border were Medicaid users (4.55% versus 9.64%, respectively). In contrast, the use of employer insurance was significantly more prevalent in non-border areas (14.00%) versus border locations (8.20%)

The majority (67.5%) of all individuals who had undergone an LEA were classified as having moderate diabetes. There were no statistically significant differences in severity of illness between border and non-border patients.

The prevalence of hypertension, CVD, stroke, depression, and renal disease was similar for both border and non- border residents that had undergone an LEA. There was a statistically significant difference between the two groups in prevalence of COPD, which was more common among individuals liv-ing in non-border versus border counties (12.53% versus 8.68%; P < 0.001).

Table 2 presents detailed results from the univariate (unadjusted) and multivariate (adjusted) logistic regression analyses. In the multivariate analyses, males were more likely to have undergone an LEA than females. Being Hispanic or African American was significantly correlated with LEA. Age was another factor significantly correlated with amputations: persons between the ages of 55 and 64 years were more likely than younger individuals (45–54 years of age) or older persons (65 and older) to have been discharged from the hospital with a diabetes-related LEA.

 

 

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