Prevalence and risk factors of preoperative malnutrition risk in older patients and its impact on surgical outcomes: a retrospective observational study

Elderly patients are vulnerable to malnutrition and we have started systematic screening for preoperative malnutrition risk in our institution. This study aims to determine the prevalence and risk factors of preoperative malnutrition risk among elderly surgical patients, and its impact on surgical outcomes. In this retrospective cohort study of patients ≥ 65 yr old undergoing elective surgery, we recorded demographics, medications, preoperative effort tolerance, Malnutrition Universal Screening Tool (MUST) score, American Society of Anesthesiologists physical status (ASA), Charlson Comorbidity Index (CCI), and Edmonton Frailty Score (EFS). Postoperative complications based on the Clavien–Dindo (CD) classification and hospital length of stay (LOS) were also recorded. Of the 1,033 patients studied, 123 (11.9%) were at risk of malnutrition (MUST ≥ 1), with 48 (4.6%) at high risk (MUST ≥ 2). Unadjusted predictors for high malnutrition risk included ASA ≥ III, higher EFS, higher CCI, polypharmacy (≥ ten medications), poor effort tolerance (metabolic equivalent of tasks < 3), malignancy, general surgery patients, and lower hemoglobin. These patients had higher odds of CD grade ≥ 1 complications compared with those without risk (adjusted odds ratio, 2.30; 95% confidence interval [CI], 1.11 to 4.78; P = 0.025) and 22% longer hospital LOS (adjusted incidence rate ratio,1.22; 95% CI, 1.00 to 1.49; P = 0.049) after multivariate adjustment for sex, severity of surgery, comorbidities, frailty, malignancy, and anemia. Preoperative malnutrition risk is prevalent among the elderly. Patients at high malnutrition risk have increased risk of postoperative complications and longer hospital LOS. Patients with high comorbidity burden and frailty should be screened for malnutrition so that nutritional optimization can be sought.