Risk Factors for Unplanned Readmission and Stump Complications following Major Lower Extremity Amputation

Abstract

Unplanned 30-day readmission rates (a marker of quality of patient care) after major lower extremity amputation are limited. We evaluated predictors of readmission at our institution. We conducted a retrospective review of all patients undergoing above-knee (AKA) or below-knee amputation (BKA) with closure between November 2007 and November 2014. Patient demographics were collected. Predictors of unplanned 30-day readmission and stump complications were determined by multivariable logistic regression. We identified 811 patients (AKA 325; BKA 486). The overall 30-day readmission rate was 26.3% (AKA 24.3%; BKA 27.6%). The cohort consisted of 54% men and had a mean age of 68.7 ± 14.9 years. Stump complications accounted for 25.8% of readmissions (AKA 20.0%; BKA 80.0%). Other common diagnoses included sepsis (27.7%), infection without the diagnosis of sepsis (9.9%), congestive heart failure exacerbation (7.0%), and diabetes-related complications (6.6%). Surgical intervention was performed on 61.8% of stump complications (AKA 11.8%; BKA 88.2%). BKA stump complications were converted to AKAs in 34.1% of cases. None of the AKA stump complications required a higher level of amputation (ie, hip disarticulation). Independent predictors of 30-day readmission included previous contralateral or ipsilateral major amputation, American Society of Anesthesiologists class 4, end-stage renal disease, and gangrene as the indication for the index procedure. Independent predictors of 30-day readmission for stump complications included previous major amputation, BKA, Hispanic ethnicity, and chronic kidney disease (stages II-V). Multivariate odds ratios (95% confidence interval) and P values are listed below (Table). The 30-day readmission rate following major lower extremity amputation is high, with wound infections accounting for a significant proportion of these readmissions. There was no difference in readmission rates based on level of amputation. However, those undergoing a BKA were more likely to present with stump complications, require a surgical intervention, and often a higher level of amputation. Identification of high-risk patients may play a role in reducing postoperative readmissions, and stump complications.TableMultivariate odds ratios (95% confidence interval) and P valuesIndependent predictors of 30-day readmissionMultivariate odds ratio (95% confidence interval)Multivariate P valuePrevious major amputation2.91 (1.77-4.78)<.01ASA 41.71 (1.15-2.51).01ESRD1.65 (1.10-2.43).01Gangrene1.51 (1.08-2.11).02Independent predictors of 30-day readmission for stump complicationsMultivariate odds ratio (95% confidence interval)Multivariate P valuePrevious major amputation12.75 (6.34-26.0)<.01BKA5.27 (2.55-11.95)<.01Hispanic ethnicity1.99 (1.08-3.66).03Chronic kidney disease2.40 (1.07-6.21).05Noninsulin-dependent diabetes0.45 (0.24-0.83).01Independent predictors of 30-day readmission for stump complications requiring surgical interventionMultivariate odds ratio (95% confidence interval)Multivariate P valuePrevious major amputation27.89 (11.91-68.43)<.01BKA13.93 (4.73-53.00)<.01Rest pain3.81 (1.30-10.24).01Hispanic Ethnicity2.57 (1.16-5.83).02AKA, Above-knee amputation; ASA, American Society of Anesthesiologists; BKA, below-knee amputation; ESRD, end-stage renal disease. Open table in a new tab