The pancreas is a major player in nutrient digestion. In chronic pancreatitis both exocrine and endocrine insufficiency may develop leading to malnutrition over time. Maldigestion is often a late complication of chronic pancreatic and depends on the severity of the underlying disease. The severity of malnutrition is correlated with two major factors: (1) malabsorption and depletion of nutrients (e.g., alcoholism and pain) causes impaired nutritional status; and (2) increased metabolic activity due to the severity of the disease. Nutritional deficiencies negatively affect outcome if they are not treated. Nutritional assessment and the clinical severity of the disease are important for planning any nutritional intervention. Good nutritional practice includes screening to identify patients at risk, followed by a thoroughly nutritional assessment and nutrition plan for risk patients. Treatment should be multidisciplinary and the mainstay of treatment is abstinence from alcohol, pain treatment, dietary modifications and pancreatic enzyme supplementation. To achieve energy-end protein requirements, oral supplementation might be beneficial. Enteral nutrition may be used when patients do not have sufficient calorie intake as in pylero-duodenal-stenosis, inflammation or prior to surgery and can be necessary if weight loss continues. Parenteral nutrition is very seldom used in patients with chronic pancreatitis and should only be used in case of GI-tract obstruction or as a supplement to enteral nutrition.

Chronic pancreatitis (CP) is an inflammatory disorder that causes irreversible anatomical changes and damage, including infiltration of inflammatory cells, fibrosis and calcification of the pancreas with destruction of the glandular structure and thereby affects normal digestion and absorption of nutrients.

Maldigestion is often a late complication of CP and depends on the severity of the underlying disease. The medium latency between onset of first symptoms and signs of maldigestion is about 8-9 years in alcoholic CP and more than 15 years in idiopathic non-alcoholic pancreatitis. Nutrient deficiencies are common in CP, driven by many risk factors including malabsorption, diabetes and, in alcoholic CP, alcoholism. However, deficiencies are frequently overlooked, leading to malnutrition[1,2].

The aim of this article is to discuss the definition of malnutrition and good nutritional practice in patients with CP.

Generally about 20%-50% of all patients in hospital are found at risk of undernutrition, dependent on definition, clinical setting and screening tool amended. A large part of these patients are at nutritional risk when admitted to hospital and in the majority of these, undernutrition develops negatively during hospital stay[3,4].

This can be prevented if special attention is paid to nutritional care of patients. Routine identification is paramount as a first stage in a patient’s care in order to identify at-risk patients, with a view to providing nutrition support if necessary[5,6].

Good nutritional practice for the patient starts by nutrition screening. The European Society for Clinical Nutrition and Metabolism (ESPEN) Guidelines for Nutrition Screening recommend a continuity of issues to be considered in all patients admitted to hospital (Figure 1)[6]. (1) Initially on admission, a simple nutritional screening is to be done, to identify patients at actual nutritional risk; (2) Subsequently for patients at nutritional risk, a thorough nutritional assessment is to be completed; (3) This stage leads to an individual evaluation of nutritional requirements, and a plan for nutrition therapy and care; and (4) Monitoring and defining of targeted outcome should be structured in order to reconsider therapy and care-planning. Finally, communication around results of screening, assessment, plan and monitoring should be communicated to other health care professionals, when the patient is transferred, either back to the community or to another institution[7-9].

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Figure 1 The nutritional care process including screening, plan and monitoring according to the European Society for Clinical Nutrition and Metabolism guideline[6]. REQ: Requirement.

In order to give priority to nutritional intervention for relevant patients, nutrition screening methods have been developed and validated. These screening methods regard nutritional status and acute disease. However, there is still no clear consensus agreement on a uniform definition of undernutrition or agreement for a gold standard method of screening and identification of undernutrition[10]. This also applies for patients with CP and malnutrition which has been offered numerous definitions. Simply stated, malnutrition is a sub-optimal nutrient status appearing as a consequence of nutrient deficiencies, which change body composition and functional status. However, this definition neglects the numerous causes of malnutrition. An international guideline committee has recently proposed an aetiology-based approach that incorporates a current understanding of the inflammatory response, as seen in CP and many other patients. The committee proposed the following nomenclature for nutrition diagnosis in adults in the clinical practice setting: “Starvation-related malnutrition”, for chronic starvation without inflammation i.e., anorexia nervosa, “chronic disease-related malnutrition”, when inflammation is chronic and of mild to moderate degree i.e., CP, and “acute disease or injury-related malnutrition”, i.e., CP with a serious complication in the intensive ward, that is, when inflammation is acute and of severe degree[11,12].

The causes of malnutrition in patients are thus included in its definition. As such, screening tools, which neglect to include relevant disease related parameters such as chronic or acute inflammation, may be less efficacious in identifying malnutrition risk.

Nutritional screening should be a simple and rapid process, which can be carried out by busy admitting nursing and medical staff. Most screening tools address four basic questions: recent weight loss, recent food intake, current body mass index and disease severity or some other measure of predicting risk of malnutrition. In 2003, ESPEN published guidelines for nutrition screening in the community, in the hospital and among elderly in institutions. The Nutrition Risk Screening 2002 (NRS 2002) seems to be the best validated screening tool, in terms of predictive validity, i.e., that clinical outcome improves when patients identified to be at risk are treated, however the evidence is sparse[3,5,6,9].

For adult patients in hospital it is thus suggested to use the NRS 2002 (Figure 2)[9]. A score equal to or greater than 3 generates a nutrition plan in all cases. If the patient is at risk, but metabolic or functional problems prevent a standard plan being carried out, or if there is doubt as to whether the patient is at risk, a referral should be made to an expert or expert team for a more detailed assessment.

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Figure 2 Nutrition risk screening 2002[9]. BMI: Body mass index.

According to the definition, the severity of malnutrition is correlated with two major factors: depletion of nutrients (alcoholism and pain) and malabsorption causes impaired nutritional status and increased metabolic activity due to the inflammatory component of CP (severity of disease). Generally patients at nutritional risk have an increased number of complications and a poorer outcome, but specific studies investigating this issue in CP are however not available[2,13,14].

A persistent alcohol intake, pain after a meal and maldigestion are the main causes of weight loss, and weight loss is strongly associated with maldigestion of fat[1,14,15].

It is widely acknowledged that patients with CP are often undernourished; however few studies have assessed this. In a medical rehabilitation clinic setting, 32% had a BMI < 20 kg/m²; 57% chronic diarrhea and 24% steatorrhea[2].

Others have found that patients are malnourished prior to surgery and that the problem remains after surgery in a substantial proportion of patients with CP[16]. Furthermore, lean body mass and fat mass are found to be decreased both in patients with or without residual pancreatic function[17]. Decreased lean body mass may lead to decreased functional capacity as found in 34% of patients with moderate to severe weight loss. This also affected quality of life[18]. In this study fatigue, found in 46%, also had a major impact on quality of life. In a cohort of ambulatory patients with CP (60 patients), we found 28% at nutritional risk. These patients had a lower fat- and muscle mass and a tendency to lower handgrip strength. Furthermore, handgrip strength was associated with muscle- and fat mass[19].

It has been found that 30%-50% of patients with CP have increased resting energy expenditure[20]. We found no difference between estimated (Harris-Benedict) and measured resting energy expenditure (indirect calorimetric) in a cohort of ambulatory CP patients. However, when adjusted for fat free mass and height, we found higher resting energy expenditure (around 20%) in patients with low BMI (< 20 kg/m²)[19].

Assessment of nutrition status should include a multidisciplinary approach[14], including assessment of clinical symptoms, exocrine and endocrine pancreatic function, body composition, bone health, dietary evaluation and lifestyle as illustrated in Figure 3.

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Figure 3 Nutritional assessment in patients with chronic pancreatitis. AMC: Arm muscle circumference; TSF: Triceps skin fold; HGS: Hand grip strength; BIA: Bioimpedance; REE: Resting energy expenditure; GGT: γ-glutamyl transferase; ALP: Alkaline phosphatase; PTH: Parathyroid hormone; DXA: Dexa scan.

Clinical symptoms should include routine medical history and psychical examination with special emphasis on nutrition related symptoms and risk factors (nausea, anorexia, pain, alcohol, smoking). Micronutrient status should be measured 1-2 times a year including malabsorption of fat-soluble vitamins, minerals and trace elements. Function of pancreas concerning the exocrine- and endocrine part will not be discussed in this article.

Because both weight and BMI do not take body composition into account and may be misinterpreted as a result of fluid changes including ascites and edema, further investigation and assessment may be made with anthropometrics and bioimpedance measurements, both for baseline and follow-up (i.e., every 3-6 mo), because even patients with a normal BMI may have a decreased muscle mass that further might decrease function and lead to a higher morbidity, i.e., higher incidence of postoperative complications after surgery for CP[16].

Anthropometric measurements as mid-arm circumference estimating lean body mass and triceps skinfold estimating subcutaneous fat stores can be compared with age- and gender-specific centiles and are useful especially in patients with edema or ascites and as a long-term follow-up for nutritional status[14].

Bioimpedance is easy, non-invasive, and relatively inexpensive, and can be performed in almost any subject because it is portable. ESPEN guidelines[29-31], report results for fat-free mass body fat, body cell mass total body water, extracellular water and intracellular water from various studies in healthy and ill subjects. The data suggests that bioimpedance works well in healthy subjects and in patients with stable water and electrolytes balance with a validated bioimpedance equation that is appropriate with regard to age, sex and race. Clinical use of bioimpedance in subjects at extremes of BMI ranges or with abnormal hydration cannot be recommended for routine assessment of patients until further validation has proven for bioimpedance algorithm to be accurate in such conditions. Multi-frequency- and segmental-bioimpedance may have advantages over single-frequency bioimpedance in these conditions, but further validation is necessary. Longitudinal follow-up of body composition by bioimpedance is possible in subjects with BMI 16-34 kg/m² without abnormal hydration, but must be interpreted with caution.

Since muscle function correlates closely with whole body protein, body cell mass, anthropometrically measured arm muscle mass, and even with BMI, loss of weight or muscle mass invariably results in decreased muscle strength which is reflected in deteriorating function tests as well as in prominently altered muscle morphology[32]. Reduced muscle strength is in turn associated with loss of physical functionality and with negative impact on recovery of health after illness or surgery, which partly explains the high predictive power of muscle function tests[2]. Hence, various studies have shown a close correlation between muscle strength and outcome in acute and chronic disease[32-34]. Just as measuring body composition offers a qualitative aspect of nutritional status, muscle function represents a dynamic indicator of muscle mass. Measurement of muscle function as indicator of functional as well as nutritional status has therefore gained considerable attention in the past years. Although hand grip strength correlates well with other muscle function tests such as knee extension strength or peak expiratory flow, it cannot be used as surrogate for muscle function of lower extremities when evaluating physical performance. Short term effects of nutritional therapy as e.g., refeeding of acute malnutrition are seen earlier by muscle function than by changes in body composition. Long-term nutritional therapy should result in both changes of body composition and muscle function, which should be paralleled by improvements of physical status[31,35].

Reference values for age- and gender-specific percentiles exist[36].

Resting energy expenditure (REE): Institution of appropriate nutritional therapy necessitates accurate determination of energy requirements. Data on measured REE in CP are very limited, but has shown, that weight loss is accompanied by hypermetabolism, and that between 30% and 50% of patients with CP have increased REE[20]. It may help us predict the energy level necessary to promote weight restoration and optimize nutritional rehabilitation preventing severe medical complications such as the refeeding syndrome[37]. Unfortunately, this technology is not available in the majority of the hospitals, because it requires skilled technicians and sophisticated methodologies that are costly and difficult to apply in standard clinical settings.

Predictive formulas of REE may be used as an alternative to indirect calorimetric that may be utilized by clinicians. The most cited and used predictive formula is the Harris-Benedict equation, which includes age, stature, and body weight to estimate REE[38]. However, studies are needed to validate predictive formulas vs measured resting energy expenditure by indirect calorimetric.

Bone health: Despite the reported high incidence of osteopathy in CP, no disease specific guideline exits for CP. However, extrapolating from guidelines for comparable malabsorptive diseases, calcium and vitamin D supplementation as well as regular monitoring of bone health should be an integral part of the nutrition management of CP, hence biochemistry and DXA scan should be performed regularly (i.e., once a year).

Diet: A detailed assessment of current and habitual dietary intakes should be made by a dietician for all patients at nutritional risk as indicated by the NRS 2002 screening tool. Nutrient intake may be measured by a 24-h recall interview or a diet history, and analyzed using specialized software providing detailed information about energy- and protein intake as well as fat and micronutrients intake. For evaluating specific food items a food frequency questionnaire can be used[39]. A specific diet plan should be made and follow-up visits evaluating intake compared to recommended energy- and protein intake should be employed according to clinical monitoring practice. It has been shown, that both dietary counseling and oral supplements for CP patients at nutritional risk can improve weight, BMI and decrease fecal fat excretion[40].

Lifestyle: To minimize nutritional risk factors in patients with CP, an effort should be made to investigate and eliminate possible individual barriers such as smoking and alcohol abuse. Furthermore, to assure patient compliance regarding medical treatment (i.e., treatment with enzymes) and to evaluate pain treatment (discussed in another article). Physical activity should be encouraged alongside nutritional therapy for optimal result[32-34].