Dataset Information

Developing and validating a risk score for lower-extremity amputation in patients hospitalized for a diabetic foot infection.

ABSTRACT:

Objective

Diabetic foot infection is the predominant predisposing factor to nontraumatic lower-extremity amputation (LEA), but few studies have investigated which specific risk factors are most associated with LEA. We sought to develop and validate a risk score to aid in the early identification of patients hospitalized for diabetic foot infection who are at highest risk of LEA.

Research design and methods

Using a large, clinical research database (CareFusion), we identified patients hospitalized at 97 hospitals in the U.S. between 2003 and 2007 for culture-documented diabetic foot infection. Candidate risk factors for LEA included demographic data, clinical presentation, chronic diseases, and recent previous hospitalization. We fit a logistic regression model using 75% of the population and converted the model coefficients to a numeric risk score. We then validated the score using the remaining 25% of patients.

Results

Among 3,018 eligible patients, 21.4% underwent an LEA. The risk factors most highly associated with LEA (P < 0.0001) were surgical site infection, vasculopathy, previous LEA, and a white blood cell count >11,000 per mm(3). The model showed good discrimination (c-statistic 0.76) and excellent calibration (Hosmer-Lemeshow, P = 0.63). The risk score stratified patients into five groups, demonstrating a graded relation to LEA risk (P < 0.0001). The LEA rates (derivation and validation cohorts) were 0% for patients with a score of 0 and ~50% for those with a score of ?21.

Conclusions

Using a large, hospitalized population, we developed and validated a risk score that seems to accurately stratify the risk of LEA among patients hospitalized for a diabetic foot infection. This score may help to identify high-risk patients upon admission.

SUBMITTER: Lipsky BA

PROVIDER: S-EPMC3142050 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature

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Publications

Developing and validating a risk score for lower-extremity amputation in patients hospitalized for a diabetic foot infection.

Lipsky Benjamin A BA Weigelt John A JA Sun Xiaowu X Johannes Richard S RS Derby Karen G KG Tabak Ying P YP

Diabetes care 20110616 8

<h4>Objective</h4>Diabetic foot infection is the predominant predisposing factor to nontraumatic lower-extremity amputation (LEA), but few studies have investigated which specific risk factors are most associated with LEA. We sought to develop and validate a risk score to aid in the early identification of patients hospitalized for diabetic foot infection who are at highest risk of LEA.<h4>Research design and methods</h4>Using a large, clinical research database (CareFusion), we identified patie ...[more]

PMID: 21680728

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Project description:To examine the association between use of statin and nonstatin cholesterol-lowering medications and risk of nontraumatic major lower extremity amputations (LEAs) and treatment failure (LEA or death).A retrospective cohort of patients with Type I and Type 2 diabetes mellitus (diabetes) was followed for 5 years between 2004 and 2008. The follow-up exposure duration was divided into 90-day periods. Use of cholesterol-lowering agents, diabetic medications, hemoglobin A1c, body mass index, and systolic and diastolic blood pressures were observed in each period. Demographic factors were observed at baseline. Major risk factors of LEA including peripheral neuropathy, peripheral artery disease, and foot ulcers were observed at baseline and were updated for each period. LEA and deaths were assessed in each period and their hazard ratios (HRs) were estimated. The study took place in the U.S. Department of Veterans Affairs Healthcare system, and the subjects consisted of cholesterol drug-naïve patients with Type I or II diabetes who were treated in the U.S. Department of Veterans Affairs Healthcare system in 2003 and were <65 years old at the end of follow-up.Of 83,953 patients in the study cohort, 217 (0.3%) patients experienced a major LEA and 11,716 (14.0%) patients experienced an LEA or death (treatment failure) after a mean follow-up of 4.6 years. Compared with patients who did not use cholesterol-lowering agents, statin users were 35% to 43% less likely to experience an LEA (HR, 0.65; 95% confidence interval [CI], 0.42-0.99) and a treatment failure (HR, 0.57; 95% CI, 0.54-0.60). Users of other cholesterol-lowering medications were not significantly different in LEA risk (HR, 0.95; 95% CI, 0.35-2.60) but had a 41% lower risk of treatment failure (HR, 0.59; 95% CI, 0.51-0.68).This is the first study to report a significant association between statin use and diminished amputation risk among patients with diabetes. In this nonrandomized cohort, beneficial effects of statin therapy were similar to that seen in large-scale clinical trial experience. For LEA risk, those given nonstatins did not have a statistically significant benefit and its effect on LEA risk was much smaller compared with statins. Unanswered questions to be explored in future studies include a comparison of statins of moderate vs high potency in those with high risk of coronary heart disease and an exploration of whether the effects seen in this study are simply effects of cholesterol-lowering or possibly pleiotropic effects.

Project description:BACKGROUND:We aimed to explore the surgical outcomes of major lower extremity amputation (MLEA) and influencing factors at an academic tertiary referral centre in north Jordan, optimistically providing a platform for future health care policies and initiatives to improve the outcomes of MLEA in Jordan. METHODS:Clinical records of patients who had undergone MLEA between January 2012 and December 2017 were identified and retrospectively reviewed. International Classification of Diseases codes were used to identify the study cohort from a prospectively maintained computerised database. We included adult patients of both genders who underwent amputations for ischemic lower limb (acute and chronic) and diabetic foot syndrome (DFS). We excluded patients for whom MLEA surgery was performed for other indications (trauma and tumors). Outcomes of interest included patient demographics and comorbidities, type of amputation and indications, length of hospital stay (LOS), the need for revision surgery (ipsilateral conversion to a higher level of amputation), and cumulative mortality rate at 1?year. The impact of the operating surgeon's specialty (vascular vs. non-vascular surgeon) on outcomes was evaluated. RESULTS:The study cohort comprised 140 patients who underwent MLEA (110 below-knee amputations [BKA] and 30 above-knee amputations [AKA]; ratio: 3:1; 86 men; 54 women; mean age, 62.9?±?1.1?years). Comorbidities included diabetes, hypertension, dyslipidaemia, ischaemic heart disease, congestive heart failure, chronic kidney disease, stroke, and Buerger disease. The only associated comorbidity was chronic kidney disease, which was more prevalent among BKA patients (p?=?0.047). Indications for MLEA included DFS, and lower limb ischaemia. Acute limb ischaemia was more likely to be an indication for AKA (p?=?0.006). LOS was considerably longer for AKA (p?=?0.035). The cumulative mortality rate at 1?year was 30.7%. Revision surgery rates and LOS improved significantly with increased rate of vascular surgeon-led MLEA. CONCLUSIONS:In developing countries, the adverse impact of MLEA is increased because of limited resources and increased prevalence of diabetes-related foot complications. Vascular surgeon-led MLEA is associated with decreased revision rates, LOS and possibly improved outcomes, particularly when it is performed for vascular insufficiency. It is important to formulate national health care policies to improve patient outcomes in these countries.

Project description:Lower extremity amputation is often performed in patients where both lower extremities are at risk due to peripheral arterial disease or diabetes, yet the proportion of patients who progress to amputation of their contralateral limb is not well defined. We sought to determine the rate of subsequent amputation on both the ipsilateral and contralateral lower extremities following initial amputation.We conducted a retrospective review of all patients undergoing lower extremity amputation (exclusive of trauma or tumor) at our institution from 1998 to 2010. We used International Classification of Diseases-Ninth Revision codes to identify patients and procedures as well as comorbidities. Outcomes included the proportion of patients at 1 and 5 years undergoing contralateral and ipsilateral major and minor amputation stratified by initial major vs minor amputation. Cox proportional hazards regression analysis was performed to determine predictors of major contralateral amputation.We identified 1715 patients. Mean age was 67.2 years, 63% were male, 77% were diabetic, and 34% underwent an initial major amputation. After major amputation, 5.7% and 11.5% have a contralateral major amputation at 1 and 5 years, respectively. After minor amputation, 3.2% and 8.4% have a contralateral major amputation at 1 and 5 years while 10.5% and 14.2% have an ipsilateral major amputation at 1 and 5 years, respectively. Cox proportional hazards regression analysis revealed end-stage renal disease (hazard ratio [HR], 3.9; 95% confidence interval [CI], 2.3-6.5), chronic renal insufficiency (HR, 2.2; 95% CI, 1.5-3.3), atherosclerosis without diabetic neuropathy (HR, 2.9; 95% CI, 1.5-5.7), atherosclerosis with diabetic neuropathy (HR, 9.1; 95% CI, 3.7-22.5), and initial major amputation (HR, 1.8; 95% CI, 1.3-2.6) were independently predictive of subsequent contralateral major amputation.Rates of contralateral limb amputation are high and predicted by renal disease, atherosclerosis, and atherosclerosis with diabetic neuropathy. Physicians and patients should be alert to the high risk of subsequent amputation in the contralateral leg. All patients, but particularly those at increased risk, should undergo close surveillance and counseling to help prevent subsequent amputations in their contralateral lower extremity.

Project description:BackgroundPatients who undergo lower extremity amputation secondary to the complications of diabetes or peripheral artery disease have poor long-term survival. Providing patients and surgeons with individual-patient, rather than population, survival estimates provides them with important information to make individualized treatment decisions.MethodsPatients with peripheral artery disease and/or diabetes undergoing their first unilateral transmetatarsal, transtibial or transfemoral amputation were identified in the Veterans Affairs Surgical Quality Improvement Program (VASQIP) database. Stepdown logistic regression was used to develop a 1-year mortality risk prediction model from a list of 33 candidate predictors using data from three of five Department of Veterans Affairs national geographical regions. External geographical validation was performed using data from the remaining two regions. Calibration and discrimination were assessed in the development and validation samples.ResultsThe development sample included 5028 patients and the validation sample 2140. The final mortality prediction model (AMPREDICT-Mortality) included amputation level, age, BMI, race, functional status, congestive heart failure, dialysis, blood urea nitrogen level, and white blood cell and platelet counts. The model fit in the validation sample was good. The area under the receiver operating characteristic (ROC) curve for the validation sample was 0·76 and Cox calibration regression indicated excellent calibration (slope 0·96, 95 per cent c.i. 0·85 to 1·06; intercept 0·02, 95 per cent c.i. -0·12 to 0·17). Given the external validation characteristics, the development and validation samples were combined, giving a total sample of 7168.ConclusionThe AMPREDICT-Mortality prediction model is a validated parsimonious model that can be used to inform the 1-year mortality risk following non-traumatic lower extremity amputation of patients with peripheral artery disease or diabetes.

Project description:ObjectivePhysician-oriented outcomes, such as patency and amputation-free survival (AFS), have traditionally been markers of success after lower extremity revascularization. Previous studies have defined clinical success based on a composite of patient-centered outcomes and have shown this outcome to be achieved in less than 50% of patients, far lower than standard physician-oriented outcomes. The purpose of this study is to evaluate clinical success after lower extremity bypass (LEB) or peripheral vascular intervention (PVI) for tissue loss in diabetic patients treated in a multidisciplinary setting to better understand what factors are associated with success from a patient's perspective.MethodsAll patients presenting to our multidisciplinary diabetic limb preservation service from July 2012 to January 2020 were enrolled in a prospective database. Patients who underwent either LEB or PVI for ulcer or gangrene were included in the analysis. Clinical success was defined as the composite outcome of secondary patency to the point of wound healing, limb salvage for 1 year, maintenance of ambulatory status for 1 year, and survival for 6 months. Secondary outcomes included 1-year wound healing, patency, and AFS.ResultsA total of 134 revascularizations were performed in 131 patients, including 91 (68%) PVI and 43 (32%) LEB. Patients were more frequently male (64%) and black (61%), and 16% were dialysis-dependent. All patients had tissue loss (53% ulcer, 47% gangrene). There were 5 (3.7%) wound, ischemia, and foot infection stage 1, 6 (6.0%) stage 2, 29 (22%) stage 3, and 92 (69%) stage 4 limbs at the time of revascularization. Overall, 76.9% of patients preserved secondary patency to the point of wound healing, 92.5% had limb salvage for 1 year, 90.3% had maintenance of ambulatory status for 1 year, and 96.3% survived for 6 months. The clinical success composite outcome was achieved in 71.6% of patients and was not statistically different between those undergoing PVI vs LEB (69.2% vs 76.7%, P = .37). Secondary patency, limb salvage, and AFS at 1 year were 80.8% ± 3.6%, 91.8% ± 2.3%, and 83.3% ± 3.1%, respectively. Wound healing at 1 year was 84.3% ± 3.4%. The only covariate associated with clinical failure on multivariable analysis was increased age (odds ratio, 0.95; 95% confidence interval, 0.91-0.99; P = .008).ConclusionsAmong diabetic patients presenting with tissue loss, the composite outcome of patient-centered clinical success is lower than traditional physician-centered outcomes after lower extremity revascularization, mostly due to low rates of secondary patency to the point of wound healing. In the current study, clinical failure was only associated with older age and was no different after PVI compared with LEB.

Dataset Information

Developing and validating a risk score for lower-extremity amputation in patients hospitalized for a diabetic foot infection.

Objective

Research design and methods

Results

Conclusions

Publications

Developing and validating a risk score for lower-extremity amputation in patients hospitalized for a diabetic foot infection.

Similar Datasets

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