Figure. Perioperative Nutrition Screen developed by the American Society for Enhanced Recovery and Perioperative Quality Initiative. BMI indicates body mass index; yo, years old.

Urinary diversion (UD) is major surgery and patients are at high risk for perioperative complications. Malnutrition is a known modifiable predictor of postoperative morbidity and mortality.^1-3 This article will focus on the evaluation and management of patient nutrition in the perioperative setting of UD.

Identifying a malnourished surgical patient is necessary for perioperative optimization. Overweight and obese BMI is predictive of morbidity, although not mortality, after UD. Patients with BMI of ≥25 kg/m² have increased odds of 30- and 90-day complications, such as infection, wound dehiscence, ureteroenteric stricture, postoperative ileus, pulmonary complications, and acute kidney injury.¹ Underweight patients (BMI <18.5 kg/m²) are also at risk of major complications after UD.⁴ Significant attention has been given to preoperative albumin as a surrogate of preoperative nutrition. Patients with hypoalbuminemia (<3.5-3.7 g/dL) prior to UD have increased rates of 30- and 90-day complications including parastomal hernia, pulmonary complications, and increased length of stay in the hospital.¹ They also have worse survival outcomes in the 30- to 90-day period as well as in long-term (3-year) follow-up. In a large administrative data study of patients undergoing urological cancer surgery, patients undergoing radical cystectomy (RC) who had preoperative hypoalbuminemia (<3.5 g/dL) had higher rates of hospital stay >7 days and increased morbidity, although no worse mortality, compared to patients with normal albumin.⁵ It is important to recall that serum albumin is a negative acute phase reactant and is often decreased in an inflammatory state, which may be the case among patients undergoing UD for invasive cancer, radiation and surgical injury, or chronic cystitis. The American Society for Parenteral and Enteral Nutrition’s Clinical Guidelines recommend not to use albumin alone,⁶ and additional screening tools in addition to albumin can identify malnourished patients who require further evaluation and treatment in the perioperative period. One such tool is the American College of Surgeons Strong for Surgery Nutrition Screening Checklist,⁷ which incorporates elements of the Nutritional Risk Screening-2002 scoring system,⁸ as well as serum albumin for risk stratification. The American Society for Enhanced Recovery and Perioperative Quality Initiative developed the Perioperative Nutrition Screen for preoperative assessment of malnutrition (see Figure),³ which is a simple 3-question preoperative version of the validated Malnutrition Universal Screening Tool. When a patient is identified as malnourished, delay of elective surgery should be considered, when possible, to optimize their nutrition, although the necessary amount of time for intervention or thresholds where it may be safe to proceed are unknown.

Surgery induces physiological and metabolic stress that results in significantly increased protein requirements. If protein intake is insufficient, this can lead to significant catabolism and weight loss. In one study of 71 patients undergoing RC for bladder cancer, the mean postoperative weight loss was 9.5 lbs (5.2%) at 2 weeks, 14.3 lbs (7.8%) at 1 month, and 16.9 lbs (9.0%) at 2 months.⁹ Mathur et al evaluated patients undergoing UD and found that patients experienced a 7% loss in body protein during the first 2 weeks postoperatively, and they only regained 63% of this by 6 weeks.¹⁰ Current recommendations for physiologically stressed patients are a minimum of 1.5-2.0 g of protein/kg/d and 25 kcal/kg/d.³ In the preoperative setting, this can be a challenging threshold to meet. It is important to note that a recent Cochrane review of all the studies evaluating perioperative nutrition surrounding RC concluded that there was limited, low-quality evidence for any benefit of intervention.¹¹ Nonetheless, patients can be encouraged to take oral nutritional supplements (ONS) that are high protein. In a randomized trial of patients receiving either multivitamins or enriched ONS 4 weeks pre- and post-RC, the intervention group was protected against the development of postoperative sarcopenia.¹² However, there was no effect on postoperative complications. Besides ONS, perioperative immune-nutrition (IN) is a dietary supplement that is thought to modulate the immune system perturbations during surgical stress. The most studied immuno-modulating nutrients are glutamine, arginine, and omega-3 fatty acids. In gastrointestinal cancers there are several postoperative benefits to perioperative IN, including decreased postoperative infection and anastomotic leakage.¹³ There has been limited evidence of IN benefits after RC. Hamilton-Reeves et al evaluated the postoperative effects of IN with arginine or standard ONS for 5 days before and 5 days after RC in 29 patients.¹⁴ They observed no difference in 30-day postoperative morbidity, although IN lowered the infection rate at 90 days. In contrast, Lyon et al found no difference in postoperative complications when comparing 40 patients who received IN compared to 104 patients from a historical control cohort receiving RC.¹⁵

As discussed above, patients can experience significant weight and protein loss after surgery. Early feeding after UD may be beneficial. Randomized trial evidence in patients undergoing colorectal surgery demonstrates that high protein ONS until postoperative day 3 to achieve consumption of >60% of protein needs was associated with a 4.4-day reduction in length of stay (P < .001). For patients unable to consume ∼50% of their protein requirement orally, dietician consult and enteral and/or parenteral nutrition should be considered.

Nutritional therapy can also be a part of multimodal preoperative conditioning programs, also known as prehabilitation. These also include exercise training and psychological interventions. Two small, randomized trials evaluating different pre- and postoperative nutritional interventions as part of larger prehabilitation programs found no difference in hospital length of stay, 30-day readmission and complications, or 90-day mortality.^16,17 Further prospective trials are needed to evaluate prehabilitation in UD.

Patients undergoing UD can experience malnutrition, and preoperative nutrition screening is a useful tool to risk stratify patients and optimize their nutrition status. Overweight BMI and obesity, underweight BMI, and hypoalbuminemia are significantly associated with an increased risk of complications after UD. While there is strong evidence for nutritional interventions in patients undergoing major surgery, definitive prospective trials are needed to determine the benefits in patients undergoing UD.