Malnutrition = surgical risk - Specialist Nutrition Rehab


24 Apr 2024

Malnutrition = surgical risk


If your clients are scheduled for elective surgery, have you already screened them for malnutrition?


NICE guidelines for Perioperative Care in Adults, state that nutritional screening should be completed for everyone having intermediate or major/complex surgery. 1  Improving someone’s nutritional status before and after surgery is a modifiable risk factor associated with improved surgical outcomes.2


Nutritional screening should be done a minimum of 6 weeks before elective surgery (but ideally as soon as the decision for surgery is made).  This is because blood tests will need to be conducted and it takes a minimum of 4 weeks to correct any nutritional deficiencies.3  If clients are severely malnourished, it can take several months to improve their nutritional status and immune function sufficiently to withstand the stresses of surgery.  Waiting until the pre-op appointment to screen clients for malnutrition is too late, as it leaves little (if any) time to correct problems which are identified.  Clients then run the risk of having their surgery delayed because they are deemed “not fit for surgery” at the pre-op appointment.


Suboptimal nutrition increases surgical risk and can result in: (2, 4)

  • Increased risk of postoperative complications.
  • Prolonged length of hospital stay.
  • Higher rates of readmission.
  • Increased incidence of postoperative death.
  • Increased hospital costs.


To reduce complications and speed recovery, it’s important that clients are in an optimal nutritional state in order to withstand the metabolic stresses of surgery.4, 5  If clients are severely malnourished, surgery should be delayed until the person’s nutritional status improves.  If that’s not possible, even 5-10 days of preoperative nutrition therapy can lead to a 50% reduction in postoperative morbidity and fewer surgical-site infections.2


BEFORE SURGERY -> screen for malnutrition (2, 4, 6, 7)

There are several screening tools available that case managers can use to screen clients for malnutrition.  The Malnutrition Universal Screening Tool (MUST) or the Perioperative Nutrition Screen (PONS) are two of the most suitable tools.  The content of both screening tools have been summarised below.

NOTE: Please ensure all oral nutrition supplements are approved by the surgical team at the pre-op appointment.


1.  Clients at LOW RISK of malnutrition meet ALL of the following criteria:

  • BMI over 20 kg/m2; AND
  • No unplanned weight loss in the last 6 months; AND
  • Consuming 50-100% of their normal food and fluid intake.



  • No referral to dietetics required, but encourage the person to eat a nutritious diet with adequate protein.
  • Certain surgeries may still require high protein oral nutrition supplements or immunonutrition supplements (containing arginine and fish oil) for 5-14 days before and after surgery.


2.  Clients at MODERATE RISK of malnutrition answer yes to any ONE of the following:

  • BMI between 18.5 – 20 kg/m2; OR
  • 5% weight loss in the last 3-6 months.



  • Refer to a dietitian for further assessment; AND
  • Ask the GP to start clients on high protein oral nutrition supplements or immunonutrition supplements (containing arginine and fish oil) for 5-14 days before and after surgery.


3.  Clients at HIGH RISK of malnutrition answer yes to any ONE (or more) of the following:

  • BMI is less than 18.5kg/m2 (if 18 – 64 years of age); AND/OR
  • BMI is less than 20kg/m2 (if 65 years of age or older); AND/OR
  • Unintentional weight loss greater than 10% within the last 3-6 months (even if the person is considered to be overweight/obese); AND/OR
  • BMI is less than 20 kg/m2 AND unintentional weight loss greater than 5% within the last 3-6 months; AND/OR
  • Eating less than 50% of their normal intake for at least 1 week; AND/OR
  • Albumin level under 30g/L; AND/OR
  • Have a poor absorptive capacity and/or high nutrient losses and/or increased nutritional needs (e.g. Crohn’s disease; chronic diarrhoea).



  • Delay surgery until nutritional status improves; AND
  • Refer to a dietitian; AND
  • Ask GP to start clients on oral nutrition supplements for weeks/months before and after the surgery; AND
  • Help clients improve their dietary intake.


AFTER SURGERY -> implement these nutrition strategies (2, 3, 5, 8)

Postoperative nutrition therapy is also part of the “enhanced recovery after surgery” protocol.  This is to prevent post-op malnutrition, support wound healing, improve the immune response, preserve muscle mass and facilitate rapid healing and recovery.


Recommendations (when approved by the surgeon):

  • Start a high protein oral intake within 24 hours of the surgery; AND
  • Take high protein oral nutrition supplements (or immunonutrition supplements – containing arginine and fish oil), within 24 hours of surgery and continue for at least 5-7 days post-op; AND
  • Monitor weight on discharge and then weekly for at least 4 weeks to ensure weight is stable.


The NHS and private hospitals vary greatly with regards to what type of nutritional screening and/or dietetic input is offered (if any) before any type of elective surgery.  For this reason, it is highly recommended that case managers screen ALL clients for malnutrition as part of their immediate needs assessments and refer on to an NHS or private dietitian if clients are identified as being at medium or high risk of malnutrition.  This is especially important if an elective surgery is being planned.


To refer a case management client for dietetic input prior to elective surgery, contact Specialist Nutrition Rehab at 0121 384 7087 or


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Specialist Nutrition Rehab
West Midlands
B24 0PL


07787 603 863

0121 384 7087

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