HbA1c and lower-extremity amputation risk in low-income patients with diabetes

Amputation Rates and Associated Social Determinants of Health in the Most Populous US Counties

Importance

Social Determinants of Health (SDOH) have been found to be associated with health outcome disparities in patients with peripheral artery disease (PAD). However, the association of specific components of SDOH and amputation has not been well described.

Objective

To evaluate whether individual components of SDOH and race are associated with amputation rates in the most populous counties of the US.

Design, Setting, and Participants

In this population-based cross-sectional study of the 100 most populous US counties, hospital discharge rates for lower extremity amputation in 2017 were assessed using the Healthcare Cost and Utilization Project State Inpatient Database. Those data were matched with publicly available demographic, hospital, and SDOH data. Data were analyzed July 3, 2022, to March 5, 2023.

Main outcome and Measures

Amputation rates were assessed across all counties. Counties were divided into quartiles based on amputation rates, and baseline characteristics were described. Unadjusted linear regression and multivariable regression analyses were performed to assess associations between county-level amputation and SDOH and demographic factors.

Results

Amputation discharge data were available for 76 of the 100 most populous counties in the United States. Within these counties, 15.3% were African American, 8.6% were Asian, 24.0% were Hispanic, and 49.6% were non-Hispanic White; 13.4% of patients were 65 years or older. Amputation rates varied widely, from 5.5 per 100 000 in quartile 1 to 14.5 per 100 000 in quartile 4. Residents of quartile 4 (vs 1) counties were more likely to be African American (27.0% vs 7.9%, P < .001), have diabetes (10.6% vs 7.9%, P < .001), smoke (16.5% vs 12.5%, P < .001), be unemployed (5.8% vs 4.6%, P = .01), be in poverty (15.8% vs 10.0%, P < .001), be in a single-parent household (41.9% vs 28.6%, P < .001), experience food insecurity (16.6% vs 12.9%, P = .04), or be physically inactive (23.1% vs 17.1%, P < .001). In unadjusted linear regression, higher amputation rates were associated with the prevalence of several health problems, including mental distress (β, 5.25 [95% CI, 3.66-6.85]; P < .001), diabetes (β, 1.73 [95% CI, 1.33-2.15], P < .001), and physical distress (β, 1.23 [95% CI, 0.86-1.61]; P < .001) and SDOHs, including unemployment (β, 1.16 [95% CI, 0.59-1.73]; P = .03), physical inactivity (β, 0.74 [95% CI, 0.57-0.90]; P < .001), smoking, (β, 0.69 [95% CI, 0.46-0.92]; P = .002), higher homicide rate (β, 0.61 [95% CI, 0.45-0.77]; P < .001), food insecurity (β, 0.51 [95% CI, 0.30-0.72]; P = .04), and poverty (β, 0.46 [95% CI, 0.32-0.60]; P < .001). Multivariable regression analysis found that county-level rates of physical distress (β, 0.84 [95% CI, 0.16-1.53]; P = .03), Black and White racial segregation (β, 0.12 [95% CI, 0.06-0.17]; P < .001), and population percentage of African American race (β, 0.06 [95% CI, 0.00-0.12]; P = .03) were associated with amputation rate.

Conclusions and Relevance

Social determinants of health provide a framework by which the associations of environmental factors with amputation rates can be quantified and potentially used to guide interventions at the local level.

The relationship between lower extremity amputation and body mass index

OBJECTIVES

Non-traumatic lower extremity amputation (LEA) is associated with significant morbidity and mortality. Diabetes mellitus (DM) and peripheral vascular disease (PVD) are associated with increased risk for LEA. As such, DM and PVD account for 54% of all LEA's, performed in the United States annually. As obesity is highly associated with both DM and PVD, our study sought to explore the relationship between LEA and obesity defined by BMI.

METHODS

Using the National Inpatient Sample (NIS) database, a retrospective review of patients who underwent non-traumatic LEA (LEA) between 2008 and 2014 was performed. The International Classification of Diseases 9th edition (ICD-9) codes were utilized to determine the diagnoses, comorbidities, and procedures. Patient BMIs were classified as follows: Non-obese [BMI <30], Obesity class I [BMI 30-34.9], Obesity class II [BMI 35-39.9], and Obesity class III [BMI ≥40]. Predictors for LEA were compared between groups using chi-square test and binary logistic regression to identify possible underlying factors associated with LEA. We also conducted a multivariate analysis to measure the effect of multiple variables on LEA.

RESULTS

We identified 16,259 patients with non-traumatic LEA and a mean age of 59.9 years. Rate of amputation in females was lower than males at 0.35% vs 0.87% respectively (p < 0.001). Of patients that underwent amputation there was a V-shape trend based on BMI, with 30.4% in non-obese patients, 18.2% in obesity class I, 17.3% in obesity class II, and 34.1% in obesity class III. The incidence of diabetes increased with obesity class, while the incidence of PVD decreased. Interestingly, of those with DM there was an inverse relationship between amputation rate and BMI class, with LEA rates in non-obese versus obesity class III patients were 1.63% vs 0.98% respectively (p < 0.001). Similarly, patients who had both diabetes and PVD showed a downward trend in LEA rate as obesity class increased; non-obese patients had a LEA rate of 8.01%, while obesity class III had 4.65% (p < 0.001). Patients in higher income bracket have lower odds of LEA (OR 0.77, p < 0.001) compared to the lowest income patients. Also, patients with comorbidities such as PVD (OR 10.78), diabetes (OR 5.02), renal failure (OR 1.41), and hypertension (OR 1.36) had higher odds to get an LEA (p < 0.001). Individuals with obesity class III are almost at half the odds (OR 0.52) to get an LEA compared to non-obese (p < 0.001).

CONCLUSIONS

Higher BMI and female gender are protective factors against lower extremity amputation. Factors that predisposing to LEA include lower household income and certain comorbidities such as PVD, diabetes, renal failure, and hypertension. These findings warrant further research to identify patients at high risk for LEA and help develop management guidelines for targeted populations.

An Overview of Risk Factors for Diabetic Foot Amputation: An Observational, Single-centre, Retrospective Cohort Study

INTRODUCTION

Not only are early detection and treatment of diabetic foot ulcers important, but also acknowledging potential risk factors for amputation gives clinicians a considerable advantage in preventing amputations. Amputations impact both healthcare services and the physical and mental health of patients. This study aimed to investigate the risk factors for amputation in patients with diabetic foot ulcers.

METHODS

The sample for this study was patients with diabetic foot ulcers who were treated by the diabetic foot council at our hospital between 2005 and 2020. A total of 32 risk factors for amputation were identified and investigated among 518 patients.

RESULTS

Our univariate analysis showed that 24 of 32 defined risk factors were statistically significant. In the multivariate analysis using the Cox regression model, seven risk factors remained statistically significant. The risk factors most significantly associated with amputation were Wagner grading, abnormal peripheral arteries, hypertension, high thrombocyte levels, low haematocrit levels, hypercholesterolaemia and male sex, respectively. The most common cause of death in patients with diabetes who have undergone amputation is cardiovascular disease, followed by sepsis.

CONCLUSION

To enable optimum treatment of patients with diabetic foot ulcers it is important for physicians to be aware of the amputation risk factors, and thus avoid amputations. Correcting risk factors, using suitable footwear and routinely inspecting feet are crucial factors for preventing amputations in patients with diabetic foot ulcers.

Predictive factors and nomogram to evaluate the risk of below-ankle re-amputation in patients with diabetic foot

BACKGROUND

Diabetes mellitus, as the most common metabolic disease, is common worldwide and represents a crucial global health concern. The purpose of this research was to investigate the related risk factors and to develop a re-amputation risk nomogram in diabetic patients who have undergone an amputation.

METHODS

A observational analysis was performed on 459 patients who have underwent amputation for diabetic foot from January 2014 through December 2019 at the First Affiliated Hospital of Wenzhou Medical University. The least absolute shrinkage and selection operator regression and stepwise regression methods were implemented to determine risk selection for the re-amputation risk model, and the predictive nomogram was established with these features. Calibration curve, receiver operating characteristic curve, and decision curve analysis of this re-amputation nomogram were assessed.

RESULTS

Predictors contained in this predictive model included smoking, glycated hemoglobin A1c (HbA1c), ankle-brachial index (ABI) and C-reactive protein (CRP). Good discrimination with a C-index of 0.725 (95% CI, 0.6624-0.7876) and good calibration were displayed with this predictive model. The decision curve analysis showed that this re-amputation nomogram predicting risk adds more benefit than none strategy if the threshold probability of a patient was >6% and <59%.

CONCLUSIONS

This novel re-amputation nomogram incorporating smoking, glycated hemoglobin A1c (HbA1c), ankle-brachial index (ABI), C-reactive protein (CRP), and smoking could be easily used to predict individual re-amputation risk prediction in diabetic foot patients who have undergone an amputation. In the future, further analysis and external testing will be needed as much as possible to reconfirm that this new Nomogram can accurately predict the risk of toe re-amputation.

Disparities In Diabetes-Related Lower Extremity Amputations In The United States: A Systematic Review

Disparities in rates of peripheral diabetic neuropathy and lower extremity amputation exist in the United States. To investigate the factors linked to this disparity, we performed a systematic review of the literature on the subject published during the period 2000-20. Nineteen observational studies were included. Disparities in rates of lower extremity amputation were reported according to patient race, ethnicity, sex, and age; across hospital referral regions, residential area characteristics, and income estimates; and on the basis of payer type and hospital characteristics. Several of these factors were interrelated. There was a reduction in major lower extremity amputation rates among Black, Hispanic, and White patients with diabetes over time, suggesting narrowing disparities in the odds of this procedure among Black and White patients. There is a need for a national strategy that integrates public awareness, screening, early initiated multidisciplinary care, and quality measures for peripheral artery disease management, as well as neighborhood-level public health interventions, to reduce the disproportionate burden of lower extremity amputation in underserved communities.

A Population-Based Analysis of Diabetes-Related Care Measures, Foot Complications, and Amputation During the COVID-19 Pandemic in Ontario, Canada

IMPORTANCE

Deferred diabetic foot screening and delays in timely care of acute foot complications during the COVID-19 pandemic may have contributed to an increase in limb loss.

OBJECTIVE

To evaluate the association of the COVID-19 pandemic with diabetes-related care measures, foot complications, and amputation.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study included all adult residents of Ontario, Canada, with diabetes and compared the rates of selected outcomes from January 1, 2020, to February 23, 2021, vs January 1, 2019, to February 23, 2020.

MAIN OUTCOMES AND MEASURES

Comprehensive in-person diabetes care assessment, including foot examination; hemoglobin A1c (HbA1c) measurement; emergency department visit or hospitalization for diabetic foot ulceration, osteomyelitis, or gangrene; lower extremity open or endovascular revascularization; minor (toe or partial-foot) amputation; and major (above-ankle) leg amputation. Rates and rate ratios (RRs) comparing 2020-2021 vs 2019-2020 for each measure were calculated for 10-week periods, anchored relative to onset of the pandemic on March 11, 2020 (11th week of 2020).

RESULTS

On March 11, 2020, the study included 1 488 605 adults with diabetes (median [IQR] age, 65 [55-74] years; 776 665 [52.2%] men), and on March 11, 2019, the study included 1 441 029 adults with diabetes (median [IQR] age, 65 [55-74] years; 751 459 [52.1%] men). After the onset of the pandemic, rates of major amputation in 2020-2021 decreased compared with 2019-2020 levels. The RR for the prepandemic period from January 1 to March 10 was 1.05 (95% CI, 0.88-1.25), with RRs in the pandemic periods ranging from 0.86 (95% CI, 0.72-1.03) in May 20 to July 28 to 0.95 (95% CI, 0.80-1.13) in October 7 to December 15. There were no consistent differences in demographic characteristics or comorbidities of patients undergoing amputation in the 2020-2021 vs 2019-2020 periods. Rates of comprehensive in-person diabetes care assessment and HbA1c measurement declined sharply and remained below 2019-2020 levels (eg, in-person assessment, March 11 to May 19: RR, 0.28; 95% CI, 0.28-0.28). The rates of emergency department visits (eg, March 11 to May 19: RR, 0.67; 95% CI, 0.61-0.75), hospitalization (eg, March 11 to May 19: RR, 0.77; 95% CI, 0.68-0.87), open revascularization (eg, March 11 to May 19: RR, 0.66; 95% CI, 0.56-0.79), endovascular revascularization (March 11 to May 19: RR, 0.70; 95% CI, 0.61-0.81), and minor amputation (March 11 to May 19: RR, 0.70; 95% CI, 0.60-0.83) initially dropped but recovered to 2019-2020 levels over the study period.

CONCLUSIONS AND RELEVANCE

In this population-based cohort study, disruptions in care related to the COVID-19 pandemic were not associated with excess leg amputations among people living with diabetes. As the pandemic ends, improved prevention and treatment of diabetic foot complications will be necessary to maintain these positive results.

Practical use of electronic health records among patients with diabetes in scientific research

Electronic health (medical) records, which are also considered as patients’ information that are routinely collected, provide a great chance for researchers to develop an epidemiological understanding of disease. Electronic health records systems cannot develop without the advance of computer industries. While conducting clinical trials that are always costly, feasible and reasonable analysis of routine patients’ information is more cost-effective and reflective of clinical practice, which is also called real world study. Real world studies can be well supported by big data in healthcare industry. Real world studies become more and more focused and important with the development of evidence-based medicine. These big data will definitely help in making decisions, making policies and guidelines, monitoring of effectiveness and safety on new drugs or technologies. Extracting, cleaning, and analyzing such big data will be a great challenge for clinical researchers. Successful applications and developments of electronic health record in western countries (eg, disease registries, health insurance claims, etc) have provided a clear direction for Chinese researchers. However, it is still at primary stages in China. This review tries to provide a full perspective on how to translate the electronic health records into scientific achievements, for example, among patients with diabetes. As a summary in the end, resource sharing and collaborations are highly recommended among hospitals and healthcare groups.

Associations between attainment of incentivized primary care indicators and incident lower limb amputation among those with type 2 diabetes: a population-based historical cohort study

INTRODUCTION

England has invested considerably in diabetes care through such programs as the Quality and Outcomes Framework (QOF) and National Diabetes Audit (NDA). Associations between program indicators and clinical endpoints, such as amputation, remain unclear. We examined associations between primary care indicators and incident lower limb amputation.

RESEARCH DESIGN AND METHODS

This population-based retrospective cohort study, spanning 2010-2017, was comprised of adults in England with type 2 diabetes and no history of lower limb amputation. Exposures at baseline (2010-2011) were attainment of QOF glycated hemoglobin (HbA1c), blood pressure and total cholesterol indicators, and number of NDA processes completed. Propensity score matching was performed and multivariable Cox proportional hazards models, adjusting for disease-related, comorbidity, lifestyle, and sociodemographic factors, were fitted using matched samples for each exposure.

RESULTS

83 688 individuals from 330 English primary care practices were included. Mean follow-up was 3.9 (SD 2.0) years, and 521 (0.6%) minor or major amputations were observed (1.62 per 1000 person-years). HbA1c and cholesterol indicator attainment were associated with considerably lower risks of minor or major amputation (adjusted HRs; 95% CIs) 0.61 (0.49 to 0.74; p<0.0001) and 0.67 (0.53 to 0.86; p=0.0017), respectively). No evidence of association between blood pressure indicator attainment and amputation was observed (adjusted HR 0.88 (0.73 to 1.06; p=0.1891)). Substantially lower amputation rates were observed among those completing a greater number of NDA care processes (adjusted HRs 0.45 (0.24 to 0.83; p=0.0106), 0.67 (0.47 to 0.97; p=0.0319), and 0.38 (0.20 to 0.70; p=0.0022) for comparisons of 4-6 vs 0-3, 7-9 vs 0-3, and 7-9 vs 4-6 processes, respectively). Results for major-only amputations were similar for HbA1c and blood pressure, though cholesterol indicator attainment was non-significant.

CONCLUSIONS

Comprehensive primary care-based secondary prevention may offer considerable protection against diabetes-related amputation. This has important implications for diabetes management and medical decision-making for patients, as well as type 2 diabetes quality improvement programs.

Temporal Trends in Incidence Rates of Lower Extremity Amputation and Associated Risk Factors Among Patients Using Veterans Health Administration Services From 2008 to 2018

IMPORTANCE

Lower extremity amputation (LEA) is associated with significant morbidity and mortality. However, national temporal trends of LEA incidence rates among US veterans and associated factors have not been well characterized.

OBJECTIVE

To describe the temporal trends of LEA, characterize associated risk factors, and decompose the associations of these risk factors with changes in temporal trends of LEA among US veterans using Department of Veteran Affairs (VA) services between 2008 and 2018.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used VA data from 2008 to 2018 to estimate incidence rates of LEA among veterans using VA services. Cox regression models were used to identify risk factors associated with LEA. Decomposition analyses estimated the associations of changes in prevalence of risk factors with changes in LEA rates. Data were analyzed from October 1, 2007, to September 30, 2018.

MAIN OUTCOMES AND MEASURES

Toe, transmetatarsal, below-knee, or above-knee LEA.

RESULTS

A total of 6 493 141 veterans were included (median [interquartile range] age, 64 [54-76] years; 6 060 390 [93.4%] men). Veterans were studied for a median (interquartile range) of 10.9 (5.6-11.0) years. Between 2008 and 2018, rates of LEA increased from 12.89 (95% CI, 12.53-13.25) LEA per 10 000 persons to 18.12 (95% CI, 17.70-18.54) LEA per 10 000 persons, representing a net increase of 5.23 (95% CI, 4.68-5.78) LEA per 10 000 persons. Between 2008 and 2018, toe amputation rates increased by 3.24 (2.89-3.59) amputations per 10 000 persons, accounting for 62.0% of the total increase in LEA rates. Transmetatarsal amputations increased by 1.54 (95% CI, 1.27-1.81) amputations per 10 000 persons; below-knee amputation rates increased by 0.81 (95% CI, 0.56-1.05) amputations per 10 000 persons; and above-knee amputation rates decreased by 0.37 (95% CI, 0.14-0.59) amputations per 10 000 persons. Compared with men, women had decreased risk of any LEA (hazard ratio [HR], 0.34 [95% CI, 0.31-0.37]). Factors associated with increased risk of any LEA included Black race (HR, 1.25 [95% CI, 1.21-1.28]) or another non-White race (ie, Asian, Latino, or other; HR, 2.36 [95% CI, 2.30-2.42]), obesity (HR, 1.59 [95% CI, 1.55-1.63]), diabetes (HR, 6.38 [95% CI, 6.22-6.54]), chronic kidney disease (CKD; eg, CKD stage 5: HR, 3.94 [95% CI, 3.22-4.83]), and smoking status (eg, current smoking: HR, 1.97 [95% CI, 1.92-2.03]). Decomposition analyses suggested that while changes in demographic composition, primarily driven by increased proportion of women veterans, associated with a decrease of 0.18 (95% CI, 0.14-0.22) LEA per 10 000 persons, and decreases in smoking rates, associated with a decrease of 0.88 (95% CI, 0.79-0.97) LEA per 10 000 persons. However, these were overwhelmed by increased rates of diabetes, associated with an increase of 1.86 (95% CI, 1.72-1.99) LEA per 10 000 persons; peripheral arterial disease, associated with an increase of 1.53 (95% CI, 1.41-1.65) LEA per 10 000 persons; CKD, associated with an increase of 1.45 (95% CI, 1.33-1.57) LEA per 10 000 persons; and other clinical factors, including body mass index, cancer, cardiovascular disease, cerebrovascular disease, chronic lung disease, dementia, and hypertension, associated with an increase of 1.45 (95% CI, 1.33-1.57) LEA per 10 000 persons.

CONCLUSIONS AND RELEVANCE

This cohort study found that incidence rates of LEA among veterans using VA services increased between 2008 and 2018. Efforts aimed at reducing burden of LEA should target the reduction of diabetes, peripheral arterial disease, and CKD at the individual and population levels.

Does Perioperative Hemoglobin A1c Level Affect the Incidence, Pattern and Mortality of Lower Extremity Amputation?

BACKGROUND

We hypothesized that perioperative HbA1c influenced the pattern and outcomes of Lower Extremity Amputation (LEA).

METHODS

A retrospective analysis was conducted for all patients who underwent LEA between 2000 and 2013. Patients were categorized into 5 groups according to their perioperative HbA1c values [Group 1 (<6.5%), Group 2 (6.5-7.4%), Group 3 (7.5-8.4%), Group 4 (8.5-9.4%) and Group 5 (≥9.5%)]. We identified 848 patients with LEA; perioperative HbA1c levels were available in 547 cases (Group 1: 18.8%, Group 2: 17.7%, Group 3: 15.0%, Group 4: 13.5% and Group 5: 34.9%). Major amputation was performed in 35%, 32%, 22%, 10.8% and 13.6%, respectively.

RESULTS

The overall mortality was 36.5%; of that one quarter occurred during the index hospitalization. Mortality was higher in Group 1 (57.4%) compared with Groups 2-5 (46.9%, 38.3%, 36.1% and 31.2%, respectively, p=0.001). Cox regression analysis showed that poor glycemic control (Group 4 and 5) had lower risk of mortality post-LEA [hazard ratio 0.57 (95% CI 0.35-0.93) and hazard ratio 0.46 (95% CI 0.31-0.69)]; this mortality risk persisted even after adjustment for age and sex but was statistically insignificant. The rate of LEA was greater among poor glycemic control patients; however, the mortality was higher among patients with tight control.

CONCLUSION

The effects of HbA1c on the immediate and long-term LEA outcomes and its therapeutic implications need further investigation.

Diabetic Foot Infection Presenting Systemic Inflammatory Response Syndrome: A Unique Disorder of Systemic Reaction from Infection of the Most Distal Body

Diabetic foot infection (DFI) is a major complication of diabetic foot that lead to nontraumatic lower-extremity amputation (LEA). Such distal infection of the body having systemic inflammatory response syndrome (SIRS) is rarely reported. Consecutive patients treated for limb-threatening DFI in a major diabetic foot center in Taiwan were analyzed between the years 2014 to 2017. Clinical factors, laboratory data, perfusion, extent, depth, infection and sensation (PEDIS) wound score in 519 subjects with grade 3 DFI and 203 presenting SIRS (28.1%) were compared. Major LEA and in-hospital mortality were defined as poor prognosis. Patients presenting SIRS had poor prognosis compared with those with grade 3 DFI (14.3% versus 6.6% for major LEA and 6.4% versus 3.5% for in-hospital mortality). Age, wound size, and HbA1c were independent risk factors favoring SIRS presentation. Perfusion grade 3 (odds ratio 3.37, p = 0.044) and history of major adverse cardiac events (OR 2.41, p = 0.036) were the independent factors for poor prognosis in treating patients with DFI presenting SIRS. SIRS when presented in patients with DFI is not only limb- but life-threatening as well. Clinicians should be aware of the clinical factors that are prone to develop and those affecting the prognosis in treating patients with limb-threatening foot infections.

Factors associated with lower-extremity amputation in patients with diabetic foot ulcers in a Chinese tertiary care hospital

Providing a better understanding of the risk factors for amputation in this particular region, Hunan province, in China might help patients with diabetic foot ulcers receive timely and appropriate medical care and help prevent amputation. Diabetic foot ulcer patients referred to the Third Xiangya Hospital during the period between December 2014 and September 2018 were enrolled. Participants who underwent amputations and received conservative treatments were compared using univariate and multivariate analyses to identify the independent predictors of amputation. Those who required amputation presented significantly higher levels of white blood cell counts, platelet counts, erythrocyte sedimentation rate, C-reactive protein, and glycated haemoglobin (HbA1c) levels. However, levels of haemoglobin, postprandial plasma C-peptide, triglyceride, high-density lipoprotein cholesterol, albumin, and uric acid were decreased in patients with amputations. Patients with more advanced Wagner grades had much higher rates of amputation. Multivariable-adjusted odds ratios in stepwise logistic regression model was 1.317 for HbA1c (95% CI: 1.015-1.709), 0.255 for triglyceride (95% CI: 0.067-0.975), and 20.947 for Wagner grades (95% CI: 4.216-104.080). Independent risk factors for amputation in these Chinese diabetic foot ulcer patients included an elevated HbA1c level, lower triglyceride level, and higher Wagner grades.

Treatment of Diabetes in Older Adults: An Endocrine Society* Clinical Practice Guideline

OBJECTIVE

The objective is to formulate clinical practice guidelines for the treatment of diabetes in older adults.

CONCLUSIONS

Diabetes, particularly type 2, is becoming more prevalent in the general population, especially in individuals over the age of 65 years. The underlying pathophysiology of the disease in these patients is exacerbated by the direct effects of aging on metabolic regulation. Similarly, aging effects interact with diabetes to accelerate the progression of many common diabetes complications. Each section in this guideline covers all aspects of the etiology and available evidence, primarily from controlled trials, on therapeutic options and outcomes in this population. The goal is to give guidance to practicing health care providers that will benefit patients with diabetes (both type 1 and type 2), paying particular attention to avoiding unnecessary and/or harmful adverse effects.

More than A1C: Types of success among adults with type-2 diabetes participating in a technology-enabled nurse coaching intervention

OBJECTIVE

Success in diabetes research and self-management is often defined as a significant decrease in glycated hemoglobin (A1C). The aim of this article is to explore different types of successes experienced by adults with type-2 diabetes participating in a health technology and nurse coaching clinical trial.

METHODS

A qualitative analysis was conducted using surveys and documentation from motivational interview-based coaching sessions between study nurses and intervention participants.

RESULTS

Of the 132 cases reviewed, types of success predominantly fell into five categories: 1) change in health behaviors; 2) change in mindset or awareness; 3) change in engagement with healthcare resources; 4) change in physical or emotional health; and 5) change in health indicators.

CONCLUSION

Experiences of success in diabetes are more varied than traditional A1C-based outcome models. Our findings suggest coaching and technology can assist patients to achieve a range of successes in diabetes management through goal setting, health tracking, resolving barriers, and aligning goals with factors that impact change.

PRACTICE IMPLICATIONS

While A1C reduction is a critical factor in decreasing risk of diabetes-related complications, when healthcare professionals focus on A1C as the main indicator of diabetes management success, important changes in individuals' health and well-being may be overlooked or undervalued.

Review of Socioeconomic Disparities in Lower Extremity Amputations: A Continuing Healthcare Problem in the United States

Lower extremity amputation is one of the most unfortunate, yet preventable, consequences of uncontrolled lower limb ischemia occurring secondary to diabetes mellitus or peripheral arterial disease. In the United States, racial and socioeconomic disparities are associated with significant differences seen in the incidence and type or level of lower extremity amputation among patients. Due to shifting demographics and the uncertain state of healthcare coverage, lower extremity amputation rates are only projected to increase in the future. Given the potential societal and individual costs associated with the loss of a limb, this review seeks to summarize the recent findings on disparities in the identification, treatments offered, and outcomes of lower limb ischemia in order to elucidate potential interventions at the practitioner and policy levels.

Using Indirect Measures to Identify Geographic Hot Spots of Poor Glycemic Control: Cross-sectional Comparisons With an A1C Registry

OBJECTIVE

Focusing health interventions in places with suboptimal glycemic control can help direct resources to neighborhoods with poor diabetes-related outcomes, but finding these areas can be difficult. Our objective was to use indirect measures versus a gold standard, population-based A1C registry to identify areas of poor glycemic control.

RESEARCH DESIGN AND METHODS

Census tracts in New York City (NYC) were characterized by race, ethnicity, income, poverty, education, diabetes-related emergency visits, inpatient hospitalizations, and proportion of adults with diabetes having poor glycemic control, based on A1C >9.0% (75 mmol/mol). Hot spot analyses were then performed, using the Getis-Ord Gi* statistic for all measures. We then calculated the sensitivity, specificity, positive and negative predictive values, and accuracy of using the indirect measures to identify hot spots of poor glycemic control found using the NYC A1C Registry data.

RESULTS

Using A1C Registry data, we identified hot spots in 42.8% of 2,085 NYC census tracts analyzed. Hot spots of diabetes-specific inpatient hospitalizations, diabetes-specific emergency visits, and age-adjusted diabetes prevalence estimated from emergency department data, respectively, had 88.9%, 89.6%, and 89.5% accuracy for identifying the same hot spots of poor glycemic control found using A1C Registry data. No other indirect measure tested had accuracy >80% except for the proportion of minority residents, which had 86.2% accuracy.

CONCLUSIONS

Compared with demographic and socioeconomic factors, health care utilization measures more accurately identified hot spots of poor glycemic control. In places without a population-based A1C registry, mapping diabetes-specific health care utilization may provide actionable evidence for targeting health interventions in areas with the highest burden of uncontrolled diabetes.

Risk of lower limb amputation in a national prevalent cohort of patients with diabetes

AIMS/HYPOTHESIS

Lower limb amputation is a serious complication of diabetes mellitus. Understanding how amputation risk differs by population subgroups is crucial in terms of directing preventive strategies. In this study, we describe those factors that impact amputation risk in the entire prevalent diabetic population of New Zealand.

METHODS

A national prevalent cohort of 217,207 individuals with diabetes in 2010 were followed up until the end of 2013 for lower limb amputations, and 2014 for mortality. Inpatient hospitalisation data were used to define lower limb amputation using ICD-10 codes. Cox proportional hazards models were used to describe relative hazard of amputation over the follow-up period.

RESULTS

A total of 784 individuals (3.6 cases/1000 individuals) underwent a major (above-ankle) lower limb amputation during follow-up, while 1217 (5.6/1000) underwent a minor (below ankle) amputation. The risk of major and minor amputation was 39% and 77% greater for men than women, respectively (adjusted HR: major amputation 1.39, 95% CI 1.20, 1.61; minor amputation 1.77, 95% CI 1.56, 2.00). Indigenous Māori were at 65% greater risk of above-knee amputation compared with the European/Other diabetic population (HR 1.65, 95% CI 1.37, 1.97). Amputation risk increased with increasing comorbidity burden, and peripheral vascular disease conferred the greatest independent risk of all comorbid conditions. Prior minor amputation increased the risk of subsequent major amputation by tenfold (HR 10.04, 95% CI 7.83, 12.87), and increased the risk of another minor amputation by 20-fold (HR 21.39, 95% CI 17.89, 25.57). Death was common among the total cohort, but particularly among those who underwent amputation, with more than half of those who underwent a major amputation dying within 3 years of their procedure (57%).

CONCLUSIONS/INTERPRETATION

Using a large, well-defined, national prevalent cohort of people with diabetes, we found that being male, indigenous Māori, living in deprivation, having a high comorbidity burden and/or having a previous amputation were strongly associated with subsequent risk of lower limb amputation. The use of this prevalent cohort strengthens the value of our estimates in terms of applicability to the general population, and highlights the subgroups at greatest risk of lower limb amputation.

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

Accumulating evidence suggests that smoking is associated with diabetic foot amputation. However, the currently available results are inconsistent and controversial. Therefore, the present study performed a meta-analysis to systematically review the association between smoking and diabetic foot amputation and to investigate the risk factors of diabetic foot amputation. Public databases, including PubMed and Embase, were searched prior to 29th February 2016. The heterogeneity was assessed using the Cochran's Q statistic and the I² statistic, and odds ratio (OR) and 95% confidence interval (CI) were calculated and pooled appropriately. Sensitivity analysis was performed to evaluate the stability of the results. In addition, Egger's test was applied to assess any potential publication bias. Based on the research, a total of eight studies, including five cohort studies and three case control studies were included. The data indicated that smoking significantly increased the risk of diabetic foot amputation (OR=1.65; 95% CI, 1.09-2.50; P<0.0001) compared with non-smoking. Sensitivity analysis demonstrated that the pooled analysis did not vary substantially following the exclusion of any one study. Additionally, there was no evidence of publication bias (Egger's test, t=0.1378; P=0.8958). Furthermore, no significant difference was observed between the minor and major amputation groups in patients who smoked (OR=0.79; 95% CI, 0.24-2.58). The results of the present meta-analysis suggested that smoking is a notable risk factor for diabetic foot amputation. Smoking cessation appears to reduce the risk of diabetic foot amputation.

An alternative approach to modelling HbA1c trajectories in patients with type 2 diabetes mellitus

AIMS

Time-dependent HbA1c trajectories in health economic models of type 2 diabetes mellitus (T2DM) are typically informed by the UK Prospective Diabetes Study (UKPDS). However, this approach may not accurately predict HbA1c progression in patients who do not conform to the demographic profile of the original UKPDS cohort. This study aimed to develop an alternative mathematical model (MM) to simulate HbA1c progression in T2DM.

MATERIALS AND METHODS

A systematic literature review identified studies, published between 2005 and 2015, that reported HbA1c in adult T2DM patients over a minimum duration of 18 months. Pooled data from eligible studies were used to develop an alternative MM equation for HbA1c progression, which was then contrasted with the UKPDS 68 progression equation in illustrative scenarios.

RESULTS

A total of 68 studies were eligible for data extraction (mean follow-up time 4.1 years). HbA1c progression was highly heterogeneous across studies, varying with baseline HbA1c, treatment group and patient age. The MM equation was fitted with parameters for mean baseline HbA1c (8.3%), initial change in HbA1c (-0.62%) and upper quartile of maximum observed HbA1c (9.3%). Differences in HbA1c trajectories between the MM and UKPDS approaches altered the timing of therapy escalation in illustrative scenarios.

CONCLUSIONS

The MM represents an alternative approach to simulate HbA1c trajectories in T2DM models, as UKPDS data may not adequately reflect the heterogeneity of HbA1c profiles observed in clinical studies. However, the choice of approach should ultimately be determined by the characteristics of individual patients under consideration and the clinical face validity of the modelled trajectories.

Platelet-rich plasma, bilayered acellular matrix grafting and negative pressure wound therapy in diabetic foot infection

Management and treatment of acute severe diabetic foot disease in patients with suboptimal glycaemic control is a critical issue in wound repair. This paper discusses the clinical efficacy of an aggressive surgical intervention combined with targeted use of regenerative medical therapies in limb preservation. Negative pressure wound therapy (NPWT), platelet-rich plasma (PRP), bilayered acellular matrix grafting and split-thickness skin grafting were combined to treat a patient with diabetes, foot necrotising fasciitis and gaseous gangrene. The wound was completely healed. The clinical outcome revealed that a multi-intervention strategy could be effective for large necrotising fasciitis wounds. Early clinical observation, suggests aggresive surgical intervention preserving intact tissue and targeted use of new regenerative technologies can lead to preservation of a limb.

DECLARATION OF INTEREST

The authors have received no financial support for the material presented in this study outside of the scope of standard patient care reimbursement. This work was supported by the National Natural Science Foundation of China (NO. 81500596) awarded to Dr Wuquan Deng.

The relationship of regional hemoglobin A1c testing and amputation rate among patients with diabetes

Objective The risk of leg amputation among patients with diabetes has declined over the past decade, while use of preventative measures-such as hemoglobin A1c monitoring-has increased. However, the relationship between hemoglobin A1c testing and amputation risk remains unclear. Methods We examined annual rates of hemoglobin A1c testing and major leg amputation among Medicare patients with diabetes from 2003 to 2012 across 306 hospital referral regions. We created linear regression models to study associations between hemoglobin A1c testing and lower extremity amputation. Results From 2003 to 2012, the proportion of patients who received hemoglobin A1c testing increased 10% (74% to 84%), while their rate of lower extremity amputation decreased 50% (430 to 232/100,000 beneficiaries). Regional hemoglobin A1c testing weakly correlated with crude amputation rate in both years (2003 R = -0.20, 2012 R = -0.21), and further weakened with adjustment for age, sex, and disability status (2003 R = -0.11, 2012 R = -0.17). In a multivariable model of 2012 amputation rates, hemoglobin A1c testing was not a significant predictor. Conclusion Lower extremity amputation among patients with diabetes nearly halved over the past decade but only weakly correlated with hemoglobin A1c testing throughout the study period. Better metrics are needed to understand the relationship between preventative care and amputation.

Development and validation of risk prediction equations to estimate future risk of blindness and lower limb amputation in patients with diabetes: cohort study

STUDY QUESTION

Is it possible to develop and externally validate risk prediction equations to estimate the 10 year risk of blindness and lower limb amputation in patients with diabetes aged 25-84 years?

METHODS

This was a prospective cohort study using routinely collected data from general practices in England contributing to the QResearch and Clinical Practice Research Datalink (CPRD) databases during the study period 1998-2014. The equations were developed using 763 QResearch practices (n=454,575 patients with diabetes) and validated in 254 different QResearch practices (n=142,419) and 357 CPRD practices (n=206,050). Cox proportional hazards models were used to derive separate risk equations for blindness and amputation in men and women that could be evaluated at 10 years. Measures of calibration and discrimination were calculated in the two validation cohorts.

STUDY ANSWER AND LIMITATIONS

Risk prediction equations to quantify absolute risk of blindness and amputation in men and women with diabetes have been developed and externally validated. In the QResearch derivation cohort, 4822 new cases of lower limb amputation and 8063 new cases of blindness occurred during follow-up. The risk equations were well calibrated in both validation cohorts. Discrimination was good in men in the external CPRD cohort for amputation (D statistic 1.69, Harrell's C statistic 0.77) and blindness (D statistic 1.40, Harrell's C statistic 0.73), with similar results in women and in the QResearch validation cohort. The algorithms are based on variables that patients are likely to know or that are routinely recorded in general practice computer systems. They can be used to identify patients at high risk for prevention or further assessment. Limitations include lack of formally adjudicated outcomes, information bias, and missing data.

WHAT THIS STUDY ADDS

Patients with type 1 or type 2 diabetes are at increased risk of blindness and amputation but generally do not have accurate assessments of the magnitude of their individual risks. The new algorithms calculate the absolute risk of developing these complications over a 10 year period in patients with diabetes, taking account of their individual risk factors.

FUNDING, COMPETING INTERESTS, DATA SHARING

JH-C is co-director of QResearch, a not for profit organisation which is a joint partnership between the University of Nottingham and Egton Medical Information Systems, and is also a paid director of ClinRisk Ltd. CC is a paid consultant statistician for ClinRisk Ltd.

HbA1c and all-cause mortality risk among patients with type 2 diabetes

BACKGROUND

Several prospective studies have evaluated the association between glycosylated hemoglobin (HbA1c) and death risk among diabetic patients. However, the results have been inconsistent.

METHODS

We performed a prospective study which included 13,334 men and 21,927 women with type 2 diabetes. Cox proportional hazards regression models were used to estimate the association of different levels of HbA1c with all-cause mortality.

RESULTS

During a mean follow up of 8.7 years, 4199 (2082 men and 2117 women) patients died. The multivariable-adjusted hazard ratios (HRs) of all-cause mortality associated with different levels of HbA1c at baseline (<6.0%, 6.0-6.9% [reference], 7.0-7.9, 8.0-8.9%, 9.0-9.9%, 10.0-10.9%, and ≥11.0%) were 1.06, 1.00, 1.10, 0.93, 1.26, 1.18 and 1.31 (Pnon-linear=0.008) for men, and 1.21, 1.00, 1.01, 1.08, 1.30, 1.30 and 1.74 (Pnon-linear<0.001) for women, respectively. The J-shaped association of HbA1c with all-cause mortality was confirmed among African American and white diabetic patients, patients who were more than 50 years old, never smoked or used insulin. When we used an updated mean value of HbA1c, the J-shaped association of HbA1c with the risk of all-cause mortality did not change.

CONCLUSIONS

Our study demonstrated a J-shaped association between HbA1c and the risk of all-cause mortality among men and women with type 2 diabetes. Both high and low levels of HbA1c were associated with an increased risk of all-cause mortality.

A novel approach to optimise glycaemic control in insulin users

Insulin therapy has been available for almost a century. However, its success rate is still disappointing where the majority of users sustain harmfully elevated glycated haemoglobin (HbA1c) levels. The key element essential for effective and safe insulin therapy is frequent dosage titration to overcome constant variations in insulin requirements. In reality, dosage titration is done sporadically during clinic visits. A scalable solution to this problem is being reviewed. A diabetes nurses service improves glycaemic control without overburdening the health system. The service relies on a handheld device, which provides patients with an insulin dose recommendation for each injection while using the device to monitor glucose. Similar to the approach providers use during clinical encounters, the device analyses stored glucose trends and constantly titrates insulin dosage without care providers' supervision. In this report, we describe the logic behind the technology by providing examples from users.

HbA1c and Lower Extremity Amputation Risk in Patients With Diabetes

In this meta-analysis, we aimed to assess glycosylated hemoglobin (HbA1c) level and lower extremity amputation (LEA) risk in patients with diabetes. Systematic computerized searches of the PubMed and Web of Knowledge were performed. We compared HbA1c level between groups with LEA and without LEA by meta-analysis; we also examined the dose–response relationship between HbA1c level and LEA risk. Sixteen studies were included in the meta-analysis. Eleven studies with 43 566 patients compared HbA1c between groups with and without LEA. The mean HbA1c (%) ranged from 8.3 to 12.5 in the group with LEA and from 7.4 to 11.3 in the group without LEA. The pooled weighted mean difference was 1.110 (95% confidence interval = 0.510-1.709; Z = 3.63, P = .008). The funnel plot was symmetrical, and Begg’s test ( z = 0.00, P = 1.000) and Egger’s test ( t = −0.02, P = .984) suggested no significant publication bias. Six studies with 109 933 patients included in the dose–response meta-analysis. The LEA incidence ranged from 0.3% to 14.6% between different HbA1c levels. Dose–response meta-analysis showed statistically significant association between HbA1c and LEA risk (χ2 = 65.51, P = .000). In linear model, the odds ratio for LEA incidence was 1.229 (95% confidence interval = 1.169-1.292) for every 1% HbA1c increase. In the spline model, the odds ratio of LEA risk increased with HbA1c levels, especially when HbA1c ranged from 5% to 9%. Our meta-analysis indicates that high level of HbA1c is an important risk factor for LEA in patients with diabetes. This evidence supports the strategy for lowering glucose levels to reduce amputation in patients with diabetes.

Body mass index and heart failure among patients with type 2 diabetes mellitus

BACKGROUND

Epidemiological data on the association between body mass index (BMI) and heart failure (HF) risk among diabetic patients are rare.

METHODS AND RESULTS

We performed a prospective cohort study of risk for HF among 31 155 patients with type 2 diabetes mellitus (11 468 men and 19 687 women). Cox proportional hazards regression models were used to estimate the association of different levels of BMI with HF risk. During a mean follow-up of 7.8 years, 5834 subjects developed HF (2379 men and 3455 women). The multivariable-adjusted (age, race, smoking, income, and type of insurance) hazard ratios of HF associated with BMI levels (18.5-22.9, 23-24.9, 25-29.9 [reference group], 30-34.9, 35-39.9, and ≥40 kg/m(2)) at baseline were 0.95, 1.00, 1.00, 1.16, 1.64, and 2.02 (Ptrend<0.001) for men and 1.16, 1.16, 1.00, 1.23, 1.55, and 2.01 (Pnonlinear<0.001) for women, respectively. When we used an updated mean value of BMI, the association of HF risk with BMI did not change. When stratified by age, race, smoking status, and use of antidiabetic drugs, the positive associations among men and the J-shaped associations among women were still present.

CONCLUSIONS

Our study suggests a positive association between BMI and HF risk among men and a J-shaped association between BMI and HF risk among women with type 2 diabetes mellitus.

Timing of access to secondary healthcare services and lower extremity amputations in patients with diabetes: a case-control study

OBJECTIVE

To investigate the association between timing of patient access to secondary healthcare services for diabetes management and lower extremity amputation (LEA) among patients with diabetes.

RESEARCH DESIGN AND METHODS

A case-control study was conducted in the secondary healthcare system in Ireland. Cases were 116 patients with diabetes who underwent a first major non-traumatic LEA between 2006 and 2012. Controls were 348 patients with diabetes, over 45 years, admitted to the same hospital as an emergency or electively, frequency-matched for gender, type of diabetes, and year. Data were collected for 7 years prior to the event year. ORs for LEA in patients with diabetes comparing early versus late referral from primary to secondary healthcare were calculated.

RESULTS

Statistically significant risk factors associated with LEA in patients with diabetes included being single, chronic kidney disease, hypertension, and hyperglycemia. Documented retinopathy was a significant protective factor. In unconditional logistic regression analysis adjusted for potential confounders, there was no evidence of a reduced risk of LEA among patients referred earlier to secondary healthcare for diabetes management.

CONCLUSIONS

Specialist referral may need to occur earlier than the 7-year cut-off used to demonstrate an effect on reducing LEA risk. Documented retinopathy was associated with reduced risk of LEA, most likely as a proxy for better self-care. Variation in the management of diabetes in primary care may also be impacting on outcomes. Efforts to develop more integrated care between primary and secondary services may be beneficial, rather than focusing on timing of referral to secondary healthcare.

BMI and coronary heart disease risk among low-income and underinsured diabetic patients

OBJECTIVE

The association between obesity and coronary heart disease (CHD) risk remains debatable, and no studies have assessed this association among diabetic patients. The aim of our study was to investigate the association between BMI and CHD risk among patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

The sample included 30,434 diabetic patients (10,955 men and 19,479 women) 30-95 years of age without a history of CHD or stroke in the Louisiana State University Hospital-Based Longitudinal Study.

RESULTS

During a mean follow-up period of 7.3 years, 7,414 subjects developed CHD. The multivariable-adjusted hazard ratios for CHD across levels of BMI at baseline (18.5-24.9, 25-29.9, 30-34.9, 35-39.9, and ≥40 kg/m(2)) were 1.00, 1.14 (95% CI 1.00-1.29), 1.27 (1.12-1.45), 1.54 (1.34-1.78), and 1.42 (1.23-1.64) (Ptrend < 0.001) in men and 1.00, 0.95 (0.85-1.07), 0.95 (0.84-1.06), 1.06 (0.94-1.20), and 1.09 (1.00-1.22) (Ptrend < 0.001) in women, respectively. When we used an updated mean or last visit value of BMI, the positive association between BMI and CHD risk did not change in men. However, the positive association of BMI with CHD changed to a U-shaped association in women when we used the last visit value of BMI.

CONCLUSIONS

Our study suggests that there is a positive association between BMI at baseline and during follow-up with the risk of CHD among patients with type 2 diabetes. We indicate a U-shaped association between BMI at the last visit and the risk of CHD among women with type 2 diabetes.

HDL cholesterol and cancer risk among patients with type 2 diabetes

OBJECTIVE

To investigate the relationship between HDL cholesterol (HDL-C) and cancer risk among type 2 diabetic patients.

RESEARCH DESIGN AND METHODS

We performed a retrospective cohort study of 14,169 men and 23,176 women with type 2 diabetes. Cox proportional hazards regression models were used to estimate the association of various levels of HDL cholesterol (HDL-C) with cancer risk.

RESULTS

During a mean follow-up period of 6.4 years, 3,711 type 2 diabetic patients had a cancer diagnosis. A significant inverse association between HDL-C and the risk of cancer was found among men and women. The multivariable-adjusted hazard ratios (HRs) of cancer at various levels of HDL-C at baseline (<30, 30-39.9, 40-49.9, 50-59.9, 60-69.9, 70-79.9, and ≥80 mg/dL) were 1.00, 0.87, 0.95, 1.01, 0.61, 0.45, and 0.37, respectively, in men (Ptrend = 0.027) and 1.00, 0.98, 0.88, 0.85, 0.84, 0.86, and 0.84, respectively, in women (Ptrend = 0.025). When stratified by race, BMI, smoking status, or medication use, the inverse association was still present. With an updated mean of HDL-C used in the analysis, the inverse association of HDL-C with cancer risk did not change. The inverse association substantially attenuated after excluding patients who died of or were diagnosed with cancer during the first 2 years of follow-up.

CONCLUSIONS

The study suggests an inverse association of HDL-C with cancer risk among men and women with type 2 diabetes, whereas the effect of HDL-C was partially mediated by reverse causation.

Body mass index and the risk of all-cause mortality among patients with type 2 diabetes mellitus

BACKGROUND

Several prospective studies have evaluated the association between body mass index (BMI) and death risk among patients with diabetes mellitus; however, the results have been inconsistent.

METHODS AND RESULTS

We performed a prospective cohort study of 19 478 black and 15 354 white patients with type 2 diabetes mellitus. Cox proportional hazards regression models were used to estimate the association of different levels of BMI stratification with all-cause mortality. During a mean follow-up of 8.7 years, 4042 deaths were identified. The multivariable-adjusted (age, sex, smoking, income, and type of insurance) hazard ratios for all-cause mortality associated with BMI levels (18.5-22.9, 23-24.9, 25-29.9, 30-34.9 [reference group], 35-39.9, and ≥40 kg/m(2)) at baseline were 2.12 (95% confidence interval [CI], 1.80-2.49), 1.74 (95% CI, 1.46-2.07), 1.23 (95% CI, 1.08-1.41), 1.00, 1.19 (95% CI, 1.03-1.39), and 1.23 (95% CI, 1.05-1.43) for blacks and 1.70 (95% CI, 1.42-2.04), 1.51 (95% CI, 1.27-1.80), 1.07 (95% CI, 0.94-1.21), 1.00, 1.07 (95% CI, 0.93-1.23), and 1.20 (95% CI, 1.05-1.38) for whites, respectively. When stratified by age, smoking status, patient type, or the use of antidiabetic drugs, a U-shaped association was still present. When BMI was included in the Cox model as a time-dependent variable, the U-shaped association of BMI with all-cause mortality risk did not change.

CONCLUSIONS

The present study indicated a U-shaped association of BMI with all-cause mortality risk among black and white patients with type 2 diabetes mellitus. A significantly increased risk of all-cause mortality was observed among blacks with BMI <30 kg/m(2) and ≥35 kg/m(2) and among whites with BMI <25 kg/m(2) and ≥40 kg/m(2) compared with patients with BMI of 30 to 34.9 kg/m(2).