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Study 2 Citation:  Matarese LE, Steiger E, Seidner DL, Richmond B.

Body Composition Changes in Cachectic Patients Receiving Home Parenteral Nutrition

J Parenter Enteral Nutr 2002 November-December 26(6):366-371

Departments of General Surgery, Gastroenterology, and Radiology, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195. Email for Laura Matarese matarel@ccf.org.

Click on the link at left to go to your desired page: Introduction  Page 2  Study 1  Study 2  Study 3  Study 4  Conclusion  Post-Test

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Abstract:

Clinical stability may dictate much of the course of home parenteral nutrition (HPN).  In some cases patients may be quite malnourished at baseline and require HPN for nutritional repletion.  Significant weight gain is commonly seen in patients in this circumstance. Less is known about the functional value of the body composition changes that result from HPN in a malnourished patient. In this study eight patients were prospectively studied for a period of three months on HPN.  Several measures of body composition were completed at baseline and follow-up along with diet history, physical activity, an immune measure (delayed hypersensitivity skin test or DHST), and laboratory values. Overall nutrition status was improved for weight and laboratory values. As expected the weight gain experienced over the three-month trial was primarily fat gain with some increases in bone density, while lean soft tissue (mostly muscle and organ tissues) did not significantly change.

  Key Words:

home parenteral nutrition, body composition, malnutrition, prospective trial, dual-energy X-ray absorptiometry (DXA), anthropometry, weight gain

 

Discussion:

Prior to the initiation of nutrition support, it is important to evaluate a patient’s nutritional status to help in establishing appropriate forms of nutrition support and clinical objectives.  Cachectic patients may experience deficits of both lean and fat stores. Refeeding of malnourished patients under most circumstances starts with some fat repletion before significant amounts of lean tissues are gained. This study sought to determine the amount and type of body tissues repleted in significantly malnourished patients during the first three months of HPN.

Eight adult patients met study criteria to be included in a prospective evaluation. Each patient was malnourished and required HPN for at least three months because of significant malabsorption.  Malnutrition was determined by body mass index, weight change, and physical examination. Patients had clinically stable underlying conditions that included short bowel syndrome (5), radiation enteritis (1), collagenous sprue (1), and adhesive bowel obstruction (1). Body composition measures and other nutrition assessment were completed at baseline and month three of HPN therapy.

Background on Body Composition Analysis:

In this study the body composition measures included dual-energy X-ray absorptiometry (DXA) and anthropometry. DXA scans can be conducted to determine bone mineral density and bone content, fat mass, and lean soft tissue mass. During this test, the patient lies supine for approximately 25 minutes as the machine completes a full-body scan. Results are used to estimate baseline and even small changes in body composition can be measured with excellent precision and accuracy and a minimum of radiation exposure (up to 27 mrem). While the initial cost of the machine is approximately $70,000, the information can be used in many ways, including monitoring for bone density changes and osteopenia or osteoporosis, monitoring total body soft tissues such as fat and lean tissues, and measuring for regional changes in bone and soft tissue composition. 

During this study, DXA measures were compared with the less objective and low-tech anthropometry methods.  Anthropometry included mid-upper arm circumference, triceps fatfold, and calculation of mid-upper arm muscle circumference. Results suggested that the calculated mid-upper arm muscle circumference was well correlated with measures of lean soft tissues by DXA at both baseline and the third month. In contrast, the triceps fatfold measure was well correlated with fat tissue estimates by DXA at baseline, but not at the third month suggesting that this anthropometric measure may  underestimate or otherwise not adequately reflect the fat gain seen in patients on HPN.

photo courtesy of JPI, Inc.           

Results:

All patients were initially consuming food orally as well as receiving a mean of 42.3 calories per kilogram (+/- 4.4) and 1.8 grams of amino acids/kilogram (+/- 0.2) daily, which declined to 37.5 (+/- 0.2) calories/kg and 1.6 (+/- 0.4) grams amino acids/kg daily. Oral intake of food added 19.9 (+/- 21.7) calories/kg and 0.9 (+/- 0.9) grams of protein/kg daily. 

A mean of 6 kg of weight was gained (47.7 kg at baseline and 53.6 kg at follow-up) as body mass index (from a mean of 16.6 to 18.6) and triceps fatfold (from a mean of 6.3 mm to 10.4 mm) also increased. The mid-upper arm muscle circumference remained stable for the duration of the study. These measures were well correlated with the changes shown through DXA tests with one exception. While both the triceps fatfold and fat tissues by DXA increased, the triceps fatfold did not reflect the magnitude in change seen in the full body DXA scans.

DXA tests showed that fat tissue increased significantly (p<0.001) from 5770 (+/- 2805) grams to 10581 (+/- 1980) grams during the three-month interval. Lean soft tissue did not change much at all (p=0.7). Bone mineral content of bone tissue significantly increased (p=0.047) from 2155 (+/- 429) grams to 2190 (+/- 443) grams.

Laboratory values suggested a slight improvement in serum transferrin and a similar trend in albumin. Immune tests stayed stable without showing significant improvement. Physical activity scores increased from barely able to maintain normal activities of daily living to a significant improvement (p=0.031).

Summary of Study 2

Refeeding studies have suggested that in cases of initial starvation, fat stores were well restored as an initial event. The degree of fat gain is related to the calories consumed with high calorie intake yielding about 2/3 weight gained as fat while lower calorie intakes may yield as low as 1/3 weight gained as fat. This study resulted in an average of 12.4% total weight gain with a mean of approximately 2 kg/month, which does not reflect overfeeding. Inactivity can contribute to a higher proportion of fat gain, as seen in hospital patients who tend to be immobile. These findings were predictable from past findings that stressed how patients accumulate less fat during recovery than do patients with simple starvation.

In this study, important protein stores in lean soft tissues did not significantly change. In comparison with other studies showing a small decrease in lean tissue, the difference may be that the patients in this study were metabolically stable and in the home setting (as opposed to being bed-bound in the hospital) where their activity level was improved over the three-month period.    

More typical longitudinal findings of patients on parenteral nutrition suggest a loss of bone tissue, which contrasts with the increase in bone mineral density seen during this study. The authors offered the explanation that bone loss may occur later in the duration of parenteral nutrition therapy.

Because an important goal to improve clinical outcomes is to support and rehabilitate soft lean tissues, research that concentrates on methods to improve these important functioning stores will be an important feature of parenteral nutrition studies. These methods may include improved physical activity, provision of additional or alternate types of protein, and the use of anabolic agents.

 

Click on the link at left to go to your desired page:  Introduction  Page 2  Study 1  Study 2  Study 3  Study 4  Conclusion  Post-Test

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