PhilSPEN Online Journal of Parenteral and Enteral Nutrition

(Article 9 | POJ_0006) January 2010 - January 2012

Original Clinical Investigation

The effect of adequate energy and protein intake on morbidity and mortality in surgical patients nutritionally assessed as high or low risk

Abstract | Introduction | Methodology | Results | Discussion | Conclusion | References | Back to Total Names Codes

Submitted: October 30, 2011 | Posted: January 30, 2012


Danilo C. del Rosario, MD (1), Jesús Fernando B. Inciong, MD, FPCS, FACS (1,2), Reynaldo P. Sinamban, MD, FPCS (1,2), Luisito O. Llido, MD, FPCS (1,2)

    Corresponding Author: Dr. Luisito O. Llido; Email:

Institution where research was conducted:

  1. Clinical Nutrition Service, St. Luke’s Medical Center, Quezon City, Metro-Manila, Philippines
  2. Department of Surgery, St. Luke’s Medical Center, Quezon City, Metro-Manila, Philippines


Background: The value of nutrition in the management of surgical patients still needs to be evaluated since only few clinical outcomes have been reported on the impact of nutrition therapy in high risk surgical patients.

Objective: To determine the effect of adequate energy and protein intake on morbidity and mortality in surgical patients nutritionally assessed to be low or high risk.

Methodology: Surgery patients referred to the Clinical Nutrition Service were followed up until discharge from March 1, 2007 to August 31, 2008. Inclusion criteria: underwent nutrition risk assessment, adequate intake. Data collected: malnutrition risk levels, weight on admission and discharge, calorie and protein intake, morbidity, mortality, number of complications, and length of hospital stay. Adequate intake was pegged at 75% of computed requirement. Statistical analysis: Chi-square test and Fisher’s exact test for small sample sized data, Wilcoxon rank sum test for non-normal distributed data and T-test for normal data.

Results: 104 patients had complete records (Low Risk=36; High Risk = 68); computed calorie requirement in both groups was 1500-1510 kcal/day while the protein requirement was 67.5-68 gm/day. There was no difference in: 1) calorie or protein intake in both groups, 2) mortality (high risk=22.7%; low risk=20.7%), 3) infectious complications (low risk=10.3%; high risk= 39.5%, p = 0.052, Chi Square), 4) weight loss, weight gain, and length of hospital stay; complication rate was higher in high risk group (=63.6% vs. low risk 31%, p = 0.006, Chi Square).

Conclusion: Adequate energy and protein intake resulted to no difference in mortality between high and low risk surgical patients including infections, weight change, and length of hospital stay, however, complication rate was higher in the high risk group.


KEYWORDS: surgery, nutrition risk, adequate, energy, protein, mortality, complications, cancer



The goal of nutrition therapy in surgical patients is to lessen or avoid morbidity and mortality in the post-operative period especially for the severely malnourished patients and/or at high risk of developing malnutrition related complications [1-3]. This requires an initial nutrition risk assessment on admission of all surgical patients which practice is sadly not implemented in most institutions in the country (Philippines) [4-6]. The nutrition screening and assessment process is followed by a nutrition care plan, which is designed to provide adequate nutrient intake for the patient. This process is meant to reduce nutrition related complications like wound infection, sepsis, multi-organ dysfunction, and slow wound healing [7-9]. Morbidity and mortality would be reduced and length of stay shortened [2,3,7-9]. Reports from intensive care units showed that reducing negative nutrient balance through increased nutrient delivery techniques reduced infections and improved mortality [10,11]. This study was therefore designed to find out if achieving adequate intake would also lead to improved morbidity and mortality outcomes in surgical patients, whether they are low, medium, or high nutritional risk.

The surgery department and clinical nutrition service of this institution (St. Luke’s Medical Center) joined to undertake this study with three main goals: a) to determine the effect of adequate intake on morbidity and mortality in surgical patients whether nutritionally “low risk” or “high risk”, b) to find out if there is an effect on weight change, length of hospital stay, and c) to determine whether this was achieved through enteral, parenteral or combined enteral and parenteral nutrition.



Type of Study: This was a prospective study covering the period from March 1, 2007 to August 31, 2008 where surgical patients ages 19 years old and above were referred to the clinical nutrition service for nutrition management either pre-operative or post-operative phase with or without chemotherapy and/or radiotherapy. Nutrition risk assessment and nutrition care plan were done for each patient after which the nutrient intake was monitored and documented. The main factor for inclusion in the study was the record of adequate intake of the patient. Excluded were patients who were 18 years old and younger, for medical treatment alone, those who could not be weighed, and incomplete records of adequate intake.

Nutritional assessment and risk leveling: The patients’ malnutrition risk level were assessed using a nutrition assessment form which was a modified SGA (Subjective Global Assessment) (Figure 1) designed by the Philippine Society of Parenteral and Enteral Nutrition (PHILSPEN), which has been validated in a local study [12].This nutritional assessment and risk leveling tool is a composite of Subjective Global Assessment (SGA) variables [13], BMI, percent weight loss, Total Lymphocyte Count (TLC) and serum albumin. This is scored into three levels: mild, moderate, high risk of malnutrition. Score of 3 and below means the patient is low to moderate risk of developing malnutrition related complications and score of above 3 is considered high risk of developing malnutrition related complications.


Figure 1: The Surgery Nutrition Assessment and Risk Leveling Tool


Nutrition care plan: This plan was designed by the Clinical Nutrition Service for full nutrition management of each patient and implemented once approved by the attending physician. It consists primarily of the computed nutrient requirements, nutrient formulation and mode of delivery, and manner of follow up. The Total Caloric Requirement (TCR) was calculated using actual body weight for underweight and normal patients, ideal body weight or corrected for overweight and obese patients multiplied using the following values: a) 25 kcal/kg body weight used for bedridden or b) 30 kcal/kg body weight or more for ambulatory patients. The Total Protein Requirement (TPR) was calculated using the appropriate weight multiplied by a range of factors, depending on the disease or injury process (0.6 gm to 2 gm/ kg body weight) [14].

Monitoring: Calorie count was performed at least three times a week. These are the monitored outcome variables: adequacy of intake for energy and protein, weight change, complications (wound infection, dehiscence, sepsis, organ dysfunction), morbidity, mortality, and length of stay. Adequacy of feeding was pegged at 75% of computed calorie or protein requirement [15]. Amount and method of feeding were progressed depending on the patients’ adequacy of intake. Weight on admission was recorded, every 5 days and prior to discharge with Detecto scale (©Detecto, Webb City, MO 64870) for ambulatory patients and bed scale for bedridden patients.

Statistical tools: Differences in values between the chosen variables between groups were analyzed using the independent samples t-test for normally distributed data and Wilcoxon test for non-normal distributed data. Chi square and Fisher exact test were used for categorical variables. Statistical analysis software used was the NCSS2004 /PASS 2002 [16].


Patient profile (Table 1 and 2): A total of 104 patients seen by the clinical nutrition service had complete records. There were 49/104 (47%) males and 55/104 (53%) females, for a male to female ratio of 1:1.12. There were less patients with low to moderate risk (30/94 or 31.9%), and more with high risk scores (64/94 or 68%). There was an equal distribution of adult and geriatric age group in the followed up patients. The majority of patients underwent surgery (59.6%) while the rest were distributed among readmissions for post-surgical follow up, chemotherapy, and/or radiotherapy treatments.



Outcomes of patients with adequate intake, N=67 (Table 2): There was no difference in mortality, infections, length of stay, weight gain, and weight loss between groups. The significant difference was found in the complication rate where there was a higher rate in the high risk patients (67.4%) and lower in the low risk patients (29.2%, p=0.0025, Chi Square Test). The complications are infectious and non-infectious with the non-infectious composed of the following: wound dehiscence, fistula formation, organ dysfunction or failure, inflammatory effects on bone marrow and other organ function, metastasis, and bleeding.

Outcomes among the “high risk” patients, N=43: In comparing the effect of having adequate intake or not, there was no difference in mortality, infections, length of stay, weight gain, and weight loss and again the only difference was in the presence of non-infectious complications (adequate intake group (67.4%) versus inadequate intake group (40%) (p=0.0394, Chi Square Test).

Distribution of nutrient intake sources (Table 3): The major sources of nutrient intake were oral, enteral, parenteral, combined enteral and parenteral, and intravenous dextrose. The oral route was more predominant in the low risk group (48% vs. 42%, p = 0.014, Chi Square); enteral nutrition was delivered in similar amounts in both low risk and high risk groups (31%-32%); parenteral nutrition was lower in the low risk group compared to the high risk group (36% vs. 37%, p < 0.001, Chi Square and Fisher Exact test); enteral and parenteral nutrition combinations were given which was significantly higher in the high risk group (4% vs. 0.8%, p = 0.002, Chi Square).




The nutritional assessment tool and risk leveling tool used in the study yielded a great number of patients who are at high risk of developing malnutrition or nutrition related complications (64/94 or 68%). A previous study using the same tool showed a significant number of deaths (18.4%, p <0.05, ANOVA) and complications (36.4%) in the high risk population [12]. The expected complication rate was high as predicted by this nutrition risk assessment tool.

The nutrition management by the clinical nutrition service achieved adequate intake in both groups for calorie/energy requirements: (for the low/moderate risk = 84.6% and for the high risk = 82.2%, Table 2) and for protein requirements: (low risk = 75.8% and high risk = 75.6%, Table 2). This shows that with close follow up by a clinical nutrition service, intake goals are achieved in most patients (24/30 or 80% among low risk patients and 44/64 or 68.7% among high risk patients). Although mortality rate was quite high in both groups (Low Risk = 20.7% and High Risk = 22.7%, Table 2) there was no difference between groups indicating that adequate intake had an effect in modifying this outcome for high risk patients. (Figure 2)

This result was also observed in studies on calorie intake of intensive care patients where an increase in energy intake reduced mortality rate by as much as 40% in the severely underweight patients. [17,18] The factors directly related to this change in outcome are the infection rates, weight gain, and weight loss which showed no difference between the two groups. This was further supported in a report which showed enteral nutrition reduced infectious complications. [19] The only significant difference was in the complication rate (31%, low risk vs. 63.6%, high risk, Table 2) which is a reflection of the relationship between nutritional high risk status, severity of illness and complication rate [10,11].

It is thus shown in this study that nutrition management makes a difference in the outcome of mortality and morbidity for the high risk group of surgical patients through its effect on improved nutrient intake and thus maintenance of body composition and immune status resulting to better wound healing and lesser infectious complications. It is also shown that with the awareness of a high risk status, optimum nutrition care could be delivered to avoid the expected complications related to poor or inadequate nutrient intake. The achievement of intake goals was done through a distribution of delivery methods utilizing all possible routes directed by feeding guidelines and protocols. [20] The oral route was highest in the low risk group indicating a fully functional gastrointestinal tract, however, this was not possible in high risk patients, hence more enteral and parenteral nutrition (either singly or combined) was delivered to them (Table 3).




Adequate intake in calorie and protein can be achieved in surgical patients nutritionally assessed to be low risk or high risk through the clinical nutrition service and this resulted to no difference in mortality rate, infection rate, weight loss, and length of stay. There was, however, a significant difference in over-all complication rate.



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Abstract | Introduction | Methodology | Results | Discussion | References | Back to Total Names Codes