Preoperative Nil Per Os Duration Predicts Mortality and Ambulation Following Below-Knee Amputation.

BACKGROUND: Routine use of nil per os (NPO) prior to procedures has been associated with dehydration and malnutrition leading to patient discomfort. We aim to examine how duration of NPO status affects postoperative outcomes in patients undergoing elective below-knee amputation (BKA). METHODS: We performed a retrospective chart review of 92 patients who underwent elective BKA between 2014-2022 for noninfectious indications. We performed statistical analysis using Chi-square tests, t-tests, and linear/logistic regression with odds ratio using P < .05 as our significance level. RESULTS: The mean age was 48.0 ± 16.7 years, and there were 64 (70%) male patients and 41 (45%) Black patients. Mean NPO duration was 12.9 ± 4.7 hours. Patients with longer NPO duration were associated with increased rates of postoperative stroke (P = .03). Patients with shorter NPO duration had significantly lower mean BUN on postoperative day (POD) 1 (14.5, P < .001) and POD 3 (14.1, P < .001) compared to preoperative mean BUN (16.8), however this normalized by POD 7 (19.2, P = .26). There were no changes in postoperative renal function based on baseline kidney disease status or associated with longer NPO duration. Shorter NPO duration was a predictor of increased likelihood of 1-year follow-up (OR: 2.9 [1.24-6.79], P = .01), independent ambulation (OR: 2.7 [1.03-7.34], P = .04), and decreased mortality (OR: .11 [.013-.91], P = .04). CONCLUSION: While NPO duration does not appear to result in postoperative renal dysfunction, prolonged NPO duration predicts worse rates of follow-up, ambulation, and survival and is associated with increased stroke rates.

Moderate and Severe Chronic Kidney Disease Predict Greater 5-Year Mortality following Major Lower-Extremity Amputation.

BACKGROUND: Severe chronic kidney disease (CKD) predicts greater mortality after major lower-extremity amputation (LEA), but it remains poorly understood whether patients with earlier stages of CKD share similar risk. METHODS: We assessed long-term postoperative outcomes for patients with CKD in a retrospective chart review of 565 patients who underwent atraumatic major LEA at a large tertiary referral center from 2015 to 2021. We stratified patients by renal function and compared outcomes including survival. RESULTS: Preoperative CKD diagnosis was related to many patient characteristics, co-occurred with many comorbidities, and was associated with less follow-up and survival. Kaplan-Meier and Cox Regression analyses showed significantly worse 5-year survival for major LEA patients with mild, moderate, or severe CKD compared to major LEA patients with no history of CKD at the time of amputation (P < 0.001). Severe CKD independently predicted worse mortality at 1-year (odds ratio [OR] 2.91; P = 0.003) and 5-years (OR 3.08; P < 0.001). Moderate CKD independently predicted worse 5-year mortality (OR 2.66; P = 0.029). CONCLUSIONS: This study demonstrates that moderate and severe CKD predict greater long-term mortality following major LEA when controlling for numerous potential confounders. This finding raises questions about the underlying mechanism if causal and highlights an opportunity to improve outcomes with earlier recognition and optimization CKD preoperatively.

Opioid Use Disorder in Patients Undergoing Major Lower Extremity Amputation: Prevalence and Outcomes.

INTRODUCTION: Patients with a history of Opioid Use Disorder (OUD) have higher postoperative complication rates and mortality in many settings. Yet, it remains poorly understood how the opioid epidemic has affected patients undergoing major lower extremity amputation (LEA) and whether outcomes differ by OUD status. METHODS: We conducted a retrospective chart review of all 689 patients who underwent major LEA at a large tertiary referral center from 2015 to 2021. This study assessed patient characteristics and long-term postoperative outcomes for patients with preoperative OUD. RESULTS: 133 (19.3%) patients had a lifetime history of preoperative OUD. Preoperative OUD was associated with key characteristics, comorbidities, and outcome measures. OUD was significantly associated with younger age (P < .001), black race (P = .026), single relationship status (P < .001), BMI <30 (P = .024), no primary care provider (P = .004), and Medicaid insurance (P < .001). Comorbidities significantly associated with OUD include current smoking (P < .001), Human Immunodeficiency Virus (HIV; P = .003), and history of osteomyelitis (P < .001). Preoperative OUD independently predicted lower rates of 30-60-day readmission (odds ratio [OR] .54, P = .018) and 1-12-month reamputation (OR .41, P = .006). There was no significant difference in long-term mortality and follow-up. CONCLUSION: This study demonstrates the prevalence of OUD in patients undergoing major LEA and reports associations and long-term outcomes. Our findings highlight the importance of recognizing OUD and raise questions about the mechanisms underlying its relation to rates of postoperative readmission and reamputation.

Modified Frailty Index Helps Predict Mortality and Ambulation Differences Between Genders and Racial Differences Following Major Lower Extremity Amputation.

BACKGROUND: Major lower extremity amputation (LEA) is associated with significant morbidity and mortality. The modified frailty index (mFI-5) has been used to predict outcomes including ambulation and mortality after LEA. It remains unknown for which patient demographics the mFI-5 is a reliable predictor. METHODS: This was a retrospective review of all patients who underwent a first-time major LEA at our institution from 2015 to 2022. Patients were stratified into 2 risk groups based on their mFI-5 score: non-frail (mFI<3) and frail (mFI≥3) and assessed on outcomes. RESULTS: Our sample consisted of 687 patients of whom 134 (19.6%) were considered frail and 551 (80.4%) were considered non-frail. A higher mFI-5 is associated with decreased ambulation rates (OR: 0.565, P = .004), increased hospital readmission (OR: 1.657, P = .021), and increased mortality (OR: 2.101, P = .001) following major LEA. In African American patients, frail and non-frail patients differed on readmission at 90 days (P = .008), mortality at 1 year (P = .001), ambulatory status (P < .001), and prosthesis use (P = .023). In male patients, frail and non-frail patients differed on readmission at 90 days (P = .019), death at 1 year (P = .001), and ambulatory status (P = .002). In Caucasian patients and female patients, frail and non-frail patients did not differ significantly on outcomes. DISCUSSION: The mFI-5 is a valuable predictor of outcomes following major LEA, specifically in males and African American patients. Moreover, surgeons should consider using frailty status to risk stratify patients and inform treatment plans.

Chronic Kidney Disease Predicts Greater 5-Year Mortality Following Major Limb Amputation.

Severe chronic kidney disease (CKD) predicts greater mortality after major lower extremity amputation (MLEA), but it remains poorly understood whether this finding extends to patients with earlier stages of CKD. We assessed outcomes for patients with CKD in a retrospective chart review of all patients who underwent MLEA at a large tertiary referral center from 2015 to 2021. We stratified 398 patients by glomerular filtration rate (GFR) and conducted Chi-Square and survival analysis. Preoperative CKD diagnosis was associated with many comorbidities, less 1-year follow-up, and greater 1- and 5-year mortality. Kaplan-Meier analysis showed worse 5-year survival for patients with any stage of CKD (62%) compared to patients without CKD (81%; P < .001). Greater 5-year mortality was independently predicted by moderate CKD (hazard ratio (HR) 2.37, P = .02) as well as severe CKD (HR 2.09, P = .005). These findings demonstrate the importance of identifying and treating CKD early preoperatively.