Risk Factors for Thirty-Day Readmissions After Lower Extremity Amputation in Patients With Vascular Disease

Understanding risk factors associated with readmission after lower extremity amputation may indicate targets for reducing readmission.

To evaluate factors associated with all-cause 30-day readmission after lower extremity amputation procedures.

Retrospective cohort study.

Inpatient.

A total of 2480 patients who had lower extremity amputations between 2008 and 2014 were selected from national electronic medical record database, Cerner Health Facts.

Univariate analysis of demographics, diagnoses, postoperative medications, and laboratory results were examined. Multivariate logistic regression models were used to identify characteristics independently associated with readmission overall and by amputation location-above the knee (AKA) or below the knee (BKA).

Readmission within 30 days of discharge.

More than one half of patients (1403, 57%) underwent BKA and 1077 (43%) underwent AKA. Readmission within 30 days was 22% (24.1% BKA versus 19.4% AKA, P = .005). In multivariable logistic regression, factors associated with 30-day readmission after any amputation included BKA (odds ratio [OR] 1.41, 95% confidence interval [CI] 1.15-1.74, P = .001), hypertension (OR 1.70, 95% CI 1.33-2.16), surgical-site infections (OR 1.44, 95% CI 1.02-2.04), heart failure (OR 1.39, 95% CI 1.10-1.75), discharge to a skilled nursing facility (OR 1.88, 95% CI 1.41-2.51), and emergency/urgent procedures (OR 1.32, 95% CI 1.04-1.67). At readmission, 13.3% of patients with a BKA required an AKA revision, and 21.3% had a diagnosis of surgical-site infection.

Risk factors for readmission after any amputation included cardiac comorbidities, associated postoperative medications, and discharge to a skilled nursing facility. The finding that acute arterial embolism or thrombosis and a BKA during the index admission was highly associated with readmission, combined with the high rates of 30-day conversion to an AKA when readmitted, suggests these patients more often develop stump complications or may be undertreated during the initial hospitalization.

III.