Supplementary Material for: Additional Value of Preoperative Albumin for Surgical Risk Stratification among Colorectal Cancer Patients

<b><i>Background:</i></b> BMI ≤18.5 kg/m² and preoperative weight loss may lead to inaccurate assessment of nutritional status, given the increasing prevalence of obesity. The aim of this study was to assess whether clinical evaluation of malnutrition based on these parameters is sufficient to predict complications after colorectal cancer surgery. <b><i>Materials and Methods:</i></b> The American College of Surgeons-National Quality Improvement Program database was queried from 2005 to 2018. Patients undergoing elective colorectal cancer surgery were divided into 4 groups: (1) albumin &lt;3.1 g/dL within 21 days of surgery, (2) European Society for Clinical Nutrition and Metabolism (ESPEN) 2 clinical parameters for malnutrition (≥10% loss of weight/6 months <i>plus</i> [BMI &lt;20 kg/m² if age &lt;70 years OR BMI &lt;22 kg/m² if age ≥70 years]), (3) both aforementioned criteria, and (4) none of aforementioned criteria. <b><i>Results:</i></b> Of 82,280 patients, 5,932 (7.2%) had hypoalbuminemia &lt;3.1 g/dL, 764 (0.9%) fulfilled clinical ESPEN 2 parameters, and 338 (0.4%) met both criteria. After adjusting for baseline confounders, patients in the hypoalbuminemia group had a higher risk of overall complications (odds ratio [OR] 1.92, <i>p</i> &lt; 0.05 vs. OR 1.18 in the ESPEN 2 group, <i>p</i> &lt; 0.05), major complications (OR 1.98, <i>p</i> &lt; 0.05 vs. OR 1.20, <i>p</i> &lt; 0.05), surgical complications (OR 1.77, 95% <i>p</i> &lt; 0.05 vs. OR 1.1, <i>p</i> &gt; 0.05), medical complications (OR 1.73, <i>p</i> &lt; 0.05 vs. OR 1.16, <i>p</i> &gt; 0.05), surgical site infection (OR 1.32, <i>p</i> &lt; 0.05 vs. OR 0.86, <i>p</i> &gt; 0.05), and prolonged hospitalization (OR 1.79, <i>p</i> &lt; 0.05 vs. OR 1.22, <i>p</i> &lt; 0.05). Patients who met both criteria were at highest risk. <b><i>Conclusions:</i></b> Preoperative measurement of serum albumin appears to be essential to identify patients at risk for complications after colorectal cancer surgery. Clinical evaluation through BMI and weight loss alone may underestimate surgery-associated risks in the USA.