Geographic and Socioeconomic Disparities in Major Lower Extremity Amputation Rates in Metropolitan Areas

Background Rates of major lower extremity amputation in patients with peripheral artery disease are higher in rural communities with markers of low socioeconomic status, but most Americans live in metropolitan areas. Whether amputation rates vary within US metropolitan areas is unclear, as are characteristics of high amputation rate urban communities. Methods and Results We estimated rates of major lower extremity amputation per 100 000 Medicare beneficiaries between 2010 and 2018 at the ZIP code level among ZIP codes with ≥100 beneficiaries. We described demographic characteristics of high and low amputation ZIP codes, and the association between major amputation rate and 3 ZIP code–level markers of socioeconomic status—the proportion of patients with dual eligibility for Medicaid, median household income, and Distressed Communities Index score—for metropolitan, micropolitan, and rural ZIP code cohorts. Between 2010 and 2018, 188 995 Medicare fee‐for‐service patients living in 31 391 ZIP codes with ≥100 beneficiaries had a major lower extremity amputation. The median (interquartile range) ZIP code–level number of amputations per 100 000 beneficiaries was 262 (75–469). Though nonmetropolitan ZIP codes had higher rates of major amputation than metropolitan areas, 78.2% of patients undergoing major amputation lived in metropolitan areas. Compared with ZIP codes with lower amputation rates, top quartile amputation rate ZIP codes had a greater proportion of Black residents (4.4% versus 17.5%, P <0.001). In metropolitan areas, after adjusting for clinical comorbidities and demographics, every $10 000 lower median household income was associated with a 4.4% (95% CI, 3.9–4.8) higher amputation rate, and a 10‐point higher Distressed Communities Index score was associated with a 3.8% (95% CI, 3.4%–4.2%) higher amputation rate; there was no association between the proportion of patients eligible for Medicaid and amputation rate. These findings were comparable to the associations identified across all ZIP codes. Conclusions In metropolitan areas, where most individuals undergoing lower extremity amputation live, markers of lower socioeconomic status and Black race were associated with higher rates of major lower extremity amputation. Development of community‐based tools for peripheral artery disease diagnosis and management targeted to communities with high amputation rates in urban areas may help reduce inequities in peripheral artery disease outcomes.

Diurnal Temperature Ranges in Relation to Lower Limb Amputation Rate of Diabetic Foot in South Korea: A Population Based Nationwide Study

The evidence for the association between diurnal temperature range (DTR) and diabetic foot amputations is limited. We aimed to investigate the region-specific association between DTR and the amputation rate of diabetic foot in Korean national-wide data. Daily data on DTR and the rate of diabetic foot amputations from 16 provincial capital cities in Korea were obtained (2011–2018). In this study, the latitude ranged from 33°11′ N to 38°61′ N, and we classified each region according to latitude. Region 1, which was located at a relatively high latitude, included Seoul, Incheon, Gyeonggi-do, and Gangwon-do. Region 2, which was located at a relatively low latitude, included Busan, Ulsan, Gyeonsannam-do, Gwangju, Jeollanam-do, Jeollabuk-do, and Jeju-do. The region-specific DTR effects on the amputation rate were estimated based on a quasi-Poisson generalized linear model, combined with a distributed lag non-linear model based on the self-controlled case series design. The DTR impacts were generally limited to a period of nine days, while significant effects during lag days 7–14 were only found in the cities of Seoul, Incheon, and Gyeonggi-do (10th lag day: RR [95% CI]; Seoul: 1.015, [1.001–1.029]; Incheon: 1.052 [1.006–1.101]; Gyeonggi-do: 1.018 [1.002–1.034]). In the subgroup analysis (according to the latitude), an increase of 1 °C in DTR was associated with the risk of diabetic foot in relatively high latitude regions. DTR has considerable effects on the risk of diabetic foot amputation in various provinces in Korea, and it was particularly affected by latitude. The results can inform the decisions on developing programs to protect vulnerable subpopulations from adverse impacts.

Incidence of lower limb amputation in people with and without diabetes: a nationwide 5-year cohort study in Japan

IntroductionThis study was conducted to investigate the incidence and time trend of lower limb amputation (LLA) among people with and without diabetes.Research design and methodsThis retrospective population-based cohort study was based on the national claims data in Japan, comprising a total population of 150 million. Data of all individuals who had LLA from April 2013 to March 2018 were obtained. We analysed the sex-adjusted and age-adjusted annual LLA rate (every fiscal year) in people with and without diabetes for major and minor amputation. To test for time trend, Poisson regression models were fitted.ResultsIn the 5-year period, 30 187 major and 29 299 minor LLAs were performed in Japan. The sex-adjusted and age-adjusted incidence of major and minor LLAs was 9.5 (people with diabetes, 21.8 vs people without diabetes, 2.3, per 100 000 person-years) and 14.9 (people with diabetes, 28.4 vs people without diabetes, 1.9, per 100 000 person-years) times higher, respectively, in people with diabetes compared with those without. A significant decline in the annual major amputation rate was observed (p<0.05) and the annual minor amputation rate remained stable (p=0.63) when sex, age and people with and without diabetes were included as dependent variables.ConclusionsThis is the first report of the national statistics of LLAs in Japan. The incidence of major and minor LLAs was 10 and 15 times higher, respectively, in people with diabetes compared with those without. A significant decline in the major amputation rate was observed, and the annual minor amputation rate remained stable during the observation period. This information can help to create an effective national healthcare strategy for preventing limb amputations, which affect the quality of life of patients with diabetes and add to the national healthcare expenditure.

Body composition and mortality in patients undergoing endovascular treatment for peripheral artery disease

An inverse correlation between body mass index and mortality in patients with peripheral artery disease (PAD) has been reported. However, little information is available regarding the impact of body composition on the clinical outcomes in patients with PAD. This study evaluated the relationships between the lean body mass index (LBMI), body fat % (BF%), and mortality and major amputation rate in patients with PAD. We evaluated 320 patients with PAD after endovascular treatment (EVT) enrolled from August 2015 to July 2016 and divided them into low and high LBMI and BF% groups based on their median values (17.47 kg/m2 and 22.07%, respectively). We assessed 3-year mortality and major amputation for the following patient groups: Low LBMI/Low BF%, Low LBMI/High BF%, High LBMI/Low BF%, and High LBMI/High BF%. During the median 3.1-year follow-up period, 70 (21.9%) patients died and 9 (2.9%) patients experienced major amputation. The survival rate was lower in the Low LBMI than in the High LBMI group, and was not significantly different between the Low and High BF% groups. Survival rates were lowest in the Low LBMI/Low BF% group (57.5%) and highest in the High LBMI/High BF% group (94.4%). There were no significant differences in major amputation rate between the Low LBMI and High LBMI groups, and between the Low BF% and High BF% groups. The Low LBMI and Low BF% groups were associated with an increased risk of mortality after adjustment for age, sex, frailty and conventional risk factors [hazard ratio (HR): 4.02; 95% confidence interval (CI) 2.10–7.70; p < 0.001 and HR: 4.48; 95% CI 1.58–12.68, p = 0.005, respectively], for age, sex, hemodialysis, and prior cerebral cardiovascular disease (HR: 3.63; 95% CI 1.93–6.82; p < 0.001 and HR: 4.03; 95% CI 1.43–11.42, p = 0.009, respectively) and for age, sex, and laboratory date (HR: 3.97; 95% CI 1.88–8.37; p < 0.001 and HR: 3.31; 95% CI 1.15–9.53, p = 0.026, respectively). In conclusion, Low LBMI and Low BF% were associated with poor prognosis in patients undergoing EVT for PAD, and mortality was the lowest in the High LBMI/High BF% group compared with other body composition groups.

In Patients with Lower Extremity Burns and Osteomyelitis, Diabetes Mellitus Increases Amputation Rate

In this retrospective analysis, we investigated the rate of radiologically confirmed osteomyelitis, extremity amputation and healthcare utilization in both the diabetic and non-diabetic lower extremity burn populations to determine the impact of diabetes mellitus on these outcomes. The burn registry was used to identify all patients admitted to our tertiary burn center from 2014 to 2018. Only patients with lower extremity burns (foot and/or ankle) were included. Statistical analysis was performed using Student’s t test, chi-squared test, and Fischer’s exact test. Of the 315 patients identified, 103 had a known diagnosis of diabetes mellitus and 212 did not. Seventeen patients were found to have osteomyelitis within three months of the burn injury. Fifteen of these patients had a history of diabetes. Notably, when non-diabetics were diagnosed with osteomyelitis, significant differences were observed in both length of stay and cost in comparison to their counterparts without osteomyelitis (36 vs 9 days; p=0.0003; $226,289 vs $48,818, p=0.0001). Eleven patients required an amputation and 10 (90.9%) of these patients had comorbid diabetes and documented diabetic neuropathy. Compared to non-diabetics, the diabetic cohort demonstrated both a higher average length of stay (13.7 vs 9.2 days, p-value=0.0016) and hospitalization cost ($72,883 vs $50,500, p-value=0.0058). Our findings highlight that diabetic patients with lower extremity burns are more likely to develop osteomyelitis than their non-diabetic counterparts and when osteomyelitis is present, diabetic patients have an increased amputation rate. Further study is required to develop protocols to treat this population, with the specific goal of minimizing patient morbidity and optimizing healthcare utilization.

Re-amputation in patients with diabetes-related minor amputations who underwent physical therapy during their hospitalization

Background Diabetes-related foot lesions are a major cause of non-traumatic lower limb amputations and are associated with a high re-amputation rate. Lesions can cause hindrance in activities of daily living, reduce physical function, and lower a patient’s quality of life. Physical therapy is necessary to prevent these limitations. Thus far, there has been limited investigation into the re-amputation rate in patients who have undergone physical therapy. This study aimed to elucidate modifiable risk factors for re-amputation in patients with minor amputations who were treated with physical therapy during their hospitalization. Methods This was a retrospective cohort study of 245 consecutive hospitalized patients who presented to our Wound Care Center between January 2015 and February 2018 and received physical therapy after a minor amputation. Participants were identified from admission records to surgical and physical therapy units stored in the electronic medical records. We examined re-amputations that occurred in the ipsilateral lower extremity during the 1-year post-discharge outpatient period. The maximum follow-up period was set at 1 year. We used Cox proportional hazards analysis to examine factors affecting the risk of re-amputation. Results Of the 129 patients enrolled, 42 patients (32.5%) underwent re-amputations during an average observation period of 6.2 months (range, 2.1 to 10.9 months). The factors associated with re-amputation were a requirement for hemodialysis, ankle dorsiflexion angle, and the Functional Independence Measure (FIM) ambulation score. Conclusions In diabetes patients with minor amputations, a requirement for hemodialysis, ankle dorsiflexion angle, and the FIM ambulation score were shown to be modifiable risk factors for re-amputation. This emphasizes that maintaining vascular endothelial function through lower limb muscle exercises for hemodialysis, improving ankle mobility, and relieving plantar pressure during walking are necessary to reduce the risk of re-amputation. Patients with these risk factors should be encouraged to participate in physical therapy.

Re-amputation in patients with diabetes -related minor amputations who underwent physical therapy during their hospitalization. A single-facility retrospective cohort study

Background：Diabetes-related foot lesions are a major cause of non-traumatic lower limb amputations and are associated with a high re-amputation rate. Lesions can cause hindrance in activities of daily living, reduce physical function, and lower a patient’s quality of life. Physical therapy is necessary to prevent these limitations. Thus far, there has been limited investigation into the re-amputation rate in patients who have undergone physical therapy. This study aimed to elucidate modifiable risk factors for re-amputation in patients with minor amputations who were treated with physical therapy during their hospitalization.Methods：This was a retrospective cohort study of 245 consecutive hospitalized patients who presented to our Wound Care Center between January 2015 and February 2018 and received physical therapy after a minor amputation. Participants were identified from admission records to surgical and physical therapy units stored in the electronic medical records. We examined re-amputations that occurred in the ipsilateral lower extremity during the 1-year post-discharge outpatient period. The maximum follow-up period was set at 1 year. We used Cox proportional hazards analysis to examine factors affecting the risk of re-amputation.Results: Of the 129 patients enrolled, 42 patients (32.5%) underwent re-amputations during an average observation period of 6.2 months (range, 2.1 to 10.9 months). The factors associated with re-amputation were a requirement for hemodialysis, ankle dorsiflexion angle, and the Functional Independence Measure (FIM) ambulation score.Conclusions: In diabetes patients with minor amputations, a requirement for hemodialysis, ankle dorsiflexion angle, and the FIM ambulation score were shown to be modifiable risk factors for re-amputation. This emphasizes that maintaining vascular endothelial function through lower limb muscle exercises for hemodialysis, improving ankle mobility, and relieving plantar pressure during walking are necessary to reduce the risk of re-amputation. Patients with these risk factors should be encouraged to participate in physical therapy.