Journal of Parenteral and Enteral Nutrition http://pen.sagepub.com/
Assessment of Nutritional Status K.N. Jeejeebhoy, A.S. Detsky and J.P. Baker JPEN J Parenter Enteral Nutr 1990 14: 193S DOI: 10.1177/014860719001400509 The online version of this article can be found at: http://pen.sagepub.com/content/14/5_suppl/193S
Published by: http://www.sagepublications.com
On behalf of:
The American Society for Parenteral & Enteral Nutrition
Additional services and information for Journal of Parenteral and Enteral Nutrition can be found at: Email Alerts: http://pen.sagepub.com/cgi/alerts Subscriptions: http://pen.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav Citations: http://pen.sagepub.com/content/14/5_suppl/193S.refs.html
>> Version of Record - Sep 1, 1990 What is This?
Downloaded from pen.sagepub.com at St Petersburg State University on December 27, 2013
Assessment of Nutritional Status K. N. JEEJEEBHOY,
M.B.B.S., PH.D., A. S. DETSKY, M.D.,
AND
J. P.
BAKER, M.D.
From the Department of Medicine, University of Toronto. Toronto. Ontario. Canada
function of how much error there is in the measurethemselves, so that a change can be interpreted as valid and outside the errors of’ measurement. The latter is dependent upon the range of the normal value. If the person starts off at the upper end of the normal range or outside it in a positive sense, then he or she may be classified as &dquo;normal&dquo; even though his or her measurements may have changed. Thus under these circumstances it is possible for a person to be in a negative nutritional state for a long time before anthropometric measurements fall below normal.
Studies in animals have shown that starvation or poor intake results in wasting, and feeding promotes weight gain and growth. In consequence, the nutritional status is traditionally defined in anthropometric terms.’ The question is whether these concepts are indeed valid for sick humans. In adults a number of nonnutritional factors may affect the anthropometric status of the individuals.’ For example, since the size of muscles and the skeleton is dependent on exercise,3 bedridden patients will loose muscle mass independently of malnutrition. Diseases resulting in protein loss from the gut also influence the circulating plasma protein levels and immunity independently of the lack of nutrients.4,.’; Thus all the traditional markers of malnutrition lose their specificity in the sick adult. How then can the nutritional status be defined in the adult?
is
DEFINITION OF NUTRITIONAL STATUS
Intake of a diet sufficient to meet or exceed the needs of the individual will keep the composition and function of the otherwise healthy individuals within the normal range. This equilibrium is disturbed by three processes: decreased intake, increased requirements, and altered utilization. When this disequilibrium occurs, then loss of body tissue ensues. However, lack of nutrients produces a series of metabolic changes in relation to energy and protein metabolism within hours or days6 of reducing nutrient intake, long before demonstrable anthropometric changes. As well these functional changes predict complications better than other anthropometric parameters,7,8 showing that a reduction in muscle power is a better predictor of complications than weight loss or arm muscle circumference. Thus malnutrition and its adverse consequences depend upon altered intake, functional changes, and finally anthropometric effects. ASSESSMENT OF MALNUTRITION BASED ON ANTHROPOMETRY
There are two situations which arise when assessment of nutritional status is based on anthropometry. First, detection of loss/gain of body components relative to previous measurements, and second, relating the valuers in any one person to a normal value in order to identify the person as &dquo;malnourished&dquo; or &dquo;normal.&dquo; The former
Accepted for publication, February 2, 1990.
Reprint requests: Khursheed N. Jeejeebhoy, MD. Division of Gastroenterology, Eaton Wing, Room 9-223. Toronto General Hospital, 200 Elizabeth Street, Toronto. Ontario. Canada M5G 2C4.
a
ments
Reproducibility and Errors in Measurement Estimation of weight loss. Morgan et al9 have shown that the sensitivity of correctly predicting the actual weight loss was only 0.67 and the predictive power was 0.75. Hence 33% with weight loss would be missed and 25% of those in whom there was no weight loss would be believed to have lost weight. Arm circumference and triceps shin-fold thickness. Hall et
all° studied the variance of these
measurements in 21
patients by three different observers. The coefficient of variation was 4.7% for arm circumference and 22.6% for triceps skinfold thickness. They concluded that to be able to confirm a true change in arm muscle circumference, calculated from arm circumference and triceps skin-fold thickness, the change needs to be at least 2.68 cm!
Classification of Patients Anthropometry
as
Abnormal Based
on
Symreng et all’ have indicated that because of these errors, when malnutrition is diagnosed by the presence of only one parameter, then 22% of the normal population would be classified as abnormal. Furthermore, it would result in the erroneous conclusion that 80% of hospital patients are malnourished. In cuntrast, when malnutrition is based on at least three abnormal criteria, then the proportion falls to 28% and more appropriately
predicts complications. PLASMA PROTEINS
In contrast to anthropometrics, several studies have demonstrated that a low serum albumin correlates with complications, but careful studies by Baker et a112 and Detsky et all&dquo; have shown it to be less predictive than clinical judgment. Anderson et all’ have also shown that the level of a single plasma protein predicts complications with a sensiti;it; of on1B- HF-~. However, ifanv one
193S Downloaded from pen.sagepub.com at St Petersburg State University on December 27, 2013
194S of three plasma proteins is low, then the sensitivitv to be able to predict complications rises to 60~. Buzby et aPe, have created a prognostic nutritional index calculated from multiple parameters which depends largely on the levels of plasma albumin and transferrin. However, their subjects were mainly patients with cancer. Warnold and Lundholm16 also found that the level of serum albumin was an important predictor for the development of complication in noncancer patients but serum transferrin was not as predictive. IMMUNE COMPETENCE
While it is true that immune competence
as
measured
by delayed cutaneous hypersensitivity (DCH) is reduced in malnutrition, several diseases&dquo; and drugs influence this measurement, making it a poor predictor of malnutrition in sick patients. The following factors nonspecifically alter DCH in the absence of malnutrition: (1) viral, bacterial, and granulomatous infections; (2) uremia, cirrhosis, hepatitis, trauma, burns, and hemorrhage; (3) steroids, immunosuppressants, cimetidine, coumadin, and perhaps aspirin; and (4) general anesthesia and surgery.
Hence in the critically sick patient many factors can alter DCH and render it valueless in assessing the state of nutrition. Meakins et al18 have shown that simply draining an abscess can reverse anergy. Thus all the current criteria for objective evidence of malnutrition are nonspecifically affected by diseases and are subject to wide errors. FUNCTIONAL TESTS OF MALNUTRITION
Because of these problems we examined muscle function as a specific measure of the effect of withdrawing nutrients and refeeding. The problem previously of assessing muscle function has been the inability to use methods which did not involve exercising on treadmills or bicycles. In order to study critically ill patients we had to develop a method which did not require the cooperation of the patient and was not nonspecifically affected
by sepsis, drugs, trauma, surgical intervention, and anesthesia. In order to do this we selected a method described by Merton19 and modified by Edwards~’° and used to study muscle fatigue. It consisted of measuring the contraction of the adductor pollicis muscle in response to an electrical stimulus of the ulnar nerve at the wrist. When the nerve is stimulated at the above site with unidirectional square wave pulses lasting only 50-70 psec at a range of frequencies from 10 to 50 Hz, there is a progressive increase in force with a maximum attained at 50 Hz. This is called the force-frequency curve. In addition, if the nerve is stimulated at 20 Hz for 2 sec and then the stimulus is switched off, the muscle relaxes and the rate of relaxation can be measured. Finally, if the stimulus at 20 Hz is continued, any loss of power represents fatigue of an objective nature (not due to voluntary relaxation). By studying two pure models of human starvation and refeeding, namely the starving obese subject and the anorexic patient being refed, we showed that starvation, causes the ratio of the force at 10 Hz/50-100 Hz to
double and the relaxation rate to slow from a mean of about 10% of maximal force lost/10 msec to ~ ~0-6 ~~. In addition, we showed the development of fatigue. Refeeding corrected these changes prior to gain in body nitrogen.:21~:25 In other studies Lenmarken et aF6 found the relaxation rate to be a good index of the nutritional status. More importantly, Zeiderman and McMahon’ have shown that in a group of preoperative surgical patients the combination of an abnormal force-frequency curve and slow relaxation rate was the most specific and sensitive predictor of nutritional associated complications when compared with other parameters of nutritional status such as hand-grip strength, arm muscle circumference, and albumin and transferrin levels. CLINICAL ASSESSMENT BASED ON A SUBJECTIVE GLOBAL ASSESSMENT OF THE PATIENT.
The above considerations have indicated that nutritional assessment using laboratory data alone, except for muscle function, fail to identify patients at risk of nutritionally mediated complications. This failure is in part due to the wide range of normal values (anthropometry) and in part due to the fact that disease and inactivity alone can result in the same effects on these laboratorygenerated parameters as malnutrition. Therefore, we decided to determine whether a global clinical assessment, which we later called subjective global assessment (SGA), would identify patients likely to develop nutritionally mediated complications. 12,13,27,28
Theoretical Basis of SGA The basis for this assessment’8 was to determine first whether there was a true restriction of food intake and/ or digestion and absorption and second whether there were associated effects on function and body composition of an acute nature. We hypothesized that if food intake had improved, there was low risk even though the patient was wasted and underweight. The data which showed that refeeding anorexics restored muscle function prior to body nitrogen supports these concepts.22
Methodology The assessment is made by obtaining the following six patient’s condition and scoring them as
features of the
FiG. 1.
Septic complication
Downloaded from pen.sagepub.com at St Petersburg State University on December 27, 2013
rate
(9c of patients) in SGA grades A
to
C.
195S
specificities of the carious clinical and objective The superiority of clinical judgment has been confirmed by Otto et at ’21 who showed that clinical judgment was superior to measurement of DCH in predicting postoperative infection. It should be recognized that clinical judgment is based on a composite of’ criteria ties and
parameters. 1,3
based on an estimate of (1) past nutritional intake: (2) disease process and operation affecting future intake of nutrients: (3) catabolic effect of the disease affecting the patient; and (4) current physical state in relation to weight loss, wasting, functional status, body fat loss, and other signs of malnutrition such as glossitis, edema, skin
rashes, and neuropathy. FIG. 2. Likelihood ratio for all grades A to C.
complications in relation
to
SGA
weight change (loss in past 6 months: 0 or >10%; change in past 2 weeks: increase, stable, or decrease [If there is recent weight gain then previous loss is not considered in the assessment.]); (2) dietary intake (no change or suboptimal intake, liquid diet, or hypocaloric fluids or starvation; (3) gastrointestinal symptoms for >2 weeks (nil, anorexia and nausea, vomiting, diarrhea) ; (4) functional capacity (normal, suboptimal work, ambulatory, or bedridden); (5) stress (nil, minimal, or high); and (6) physical signs (loss of subcutaneous fat over the triceps and/or chest; Muscle wasting of the deltoids, temporals, and/or quadriceps; fluid retention: edema, ascites; mucosal lesions: glossitis, skin rash suggestive of deficiency). follows: (1)
Assessment of Nutritional Status K.N. Jeejeebhoy, A.S. Detsky and J.P. Baker JPEN J Parenter Enteral Nutr 1990 14: 193S DOI: 10.1177/014860719001400509 The online version of this article can be found at: http://pen.sagepub.com/content/14/5_suppl/193S
Published by: http://www.sagepublications.com
On behalf of:
The American Society for Parenteral & Enteral Nutrition
Additional services and information for Journal of Parenteral and Enteral Nutrition can be found at: Email Alerts: http://pen.sagepub.com/cgi/alerts Subscriptions: http://pen.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav Citations: http://pen.sagepub.com/content/14/5_suppl/193S.refs.html
>> Version of Record - Sep 1, 1990 What is This?
Downloaded from pen.sagepub.com at St Petersburg State University on December 27, 2013
Assessment of Nutritional Status K. N. JEEJEEBHOY,
M.B.B.S., PH.D., A. S. DETSKY, M.D.,
AND
J. P.
BAKER, M.D.
From the Department of Medicine, University of Toronto. Toronto. Ontario. Canada
function of how much error there is in the measurethemselves, so that a change can be interpreted as valid and outside the errors of’ measurement. The latter is dependent upon the range of the normal value. If the person starts off at the upper end of the normal range or outside it in a positive sense, then he or she may be classified as &dquo;normal&dquo; even though his or her measurements may have changed. Thus under these circumstances it is possible for a person to be in a negative nutritional state for a long time before anthropometric measurements fall below normal.
Studies in animals have shown that starvation or poor intake results in wasting, and feeding promotes weight gain and growth. In consequence, the nutritional status is traditionally defined in anthropometric terms.’ The question is whether these concepts are indeed valid for sick humans. In adults a number of nonnutritional factors may affect the anthropometric status of the individuals.’ For example, since the size of muscles and the skeleton is dependent on exercise,3 bedridden patients will loose muscle mass independently of malnutrition. Diseases resulting in protein loss from the gut also influence the circulating plasma protein levels and immunity independently of the lack of nutrients.4,.’; Thus all the traditional markers of malnutrition lose their specificity in the sick adult. How then can the nutritional status be defined in the adult?
is
DEFINITION OF NUTRITIONAL STATUS
Intake of a diet sufficient to meet or exceed the needs of the individual will keep the composition and function of the otherwise healthy individuals within the normal range. This equilibrium is disturbed by three processes: decreased intake, increased requirements, and altered utilization. When this disequilibrium occurs, then loss of body tissue ensues. However, lack of nutrients produces a series of metabolic changes in relation to energy and protein metabolism within hours or days6 of reducing nutrient intake, long before demonstrable anthropometric changes. As well these functional changes predict complications better than other anthropometric parameters,7,8 showing that a reduction in muscle power is a better predictor of complications than weight loss or arm muscle circumference. Thus malnutrition and its adverse consequences depend upon altered intake, functional changes, and finally anthropometric effects. ASSESSMENT OF MALNUTRITION BASED ON ANTHROPOMETRY
There are two situations which arise when assessment of nutritional status is based on anthropometry. First, detection of loss/gain of body components relative to previous measurements, and second, relating the valuers in any one person to a normal value in order to identify the person as &dquo;malnourished&dquo; or &dquo;normal.&dquo; The former
Accepted for publication, February 2, 1990.
Reprint requests: Khursheed N. Jeejeebhoy, MD. Division of Gastroenterology, Eaton Wing, Room 9-223. Toronto General Hospital, 200 Elizabeth Street, Toronto. Ontario. Canada M5G 2C4.
a
ments
Reproducibility and Errors in Measurement Estimation of weight loss. Morgan et al9 have shown that the sensitivity of correctly predicting the actual weight loss was only 0.67 and the predictive power was 0.75. Hence 33% with weight loss would be missed and 25% of those in whom there was no weight loss would be believed to have lost weight. Arm circumference and triceps shin-fold thickness. Hall et
all° studied the variance of these
measurements in 21
patients by three different observers. The coefficient of variation was 4.7% for arm circumference and 22.6% for triceps skinfold thickness. They concluded that to be able to confirm a true change in arm muscle circumference, calculated from arm circumference and triceps skin-fold thickness, the change needs to be at least 2.68 cm!
Classification of Patients Anthropometry
as
Abnormal Based
on
Symreng et all’ have indicated that because of these errors, when malnutrition is diagnosed by the presence of only one parameter, then 22% of the normal population would be classified as abnormal. Furthermore, it would result in the erroneous conclusion that 80% of hospital patients are malnourished. In cuntrast, when malnutrition is based on at least three abnormal criteria, then the proportion falls to 28% and more appropriately
predicts complications. PLASMA PROTEINS
In contrast to anthropometrics, several studies have demonstrated that a low serum albumin correlates with complications, but careful studies by Baker et a112 and Detsky et all&dquo; have shown it to be less predictive than clinical judgment. Anderson et all’ have also shown that the level of a single plasma protein predicts complications with a sensiti;it; of on1B- HF-~. However, ifanv one
193S Downloaded from pen.sagepub.com at St Petersburg State University on December 27, 2013
194S of three plasma proteins is low, then the sensitivitv to be able to predict complications rises to 60~. Buzby et aPe, have created a prognostic nutritional index calculated from multiple parameters which depends largely on the levels of plasma albumin and transferrin. However, their subjects were mainly patients with cancer. Warnold and Lundholm16 also found that the level of serum albumin was an important predictor for the development of complication in noncancer patients but serum transferrin was not as predictive. IMMUNE COMPETENCE
While it is true that immune competence
as
measured
by delayed cutaneous hypersensitivity (DCH) is reduced in malnutrition, several diseases&dquo; and drugs influence this measurement, making it a poor predictor of malnutrition in sick patients. The following factors nonspecifically alter DCH in the absence of malnutrition: (1) viral, bacterial, and granulomatous infections; (2) uremia, cirrhosis, hepatitis, trauma, burns, and hemorrhage; (3) steroids, immunosuppressants, cimetidine, coumadin, and perhaps aspirin; and (4) general anesthesia and surgery.
Hence in the critically sick patient many factors can alter DCH and render it valueless in assessing the state of nutrition. Meakins et al18 have shown that simply draining an abscess can reverse anergy. Thus all the current criteria for objective evidence of malnutrition are nonspecifically affected by diseases and are subject to wide errors. FUNCTIONAL TESTS OF MALNUTRITION
Because of these problems we examined muscle function as a specific measure of the effect of withdrawing nutrients and refeeding. The problem previously of assessing muscle function has been the inability to use methods which did not involve exercising on treadmills or bicycles. In order to study critically ill patients we had to develop a method which did not require the cooperation of the patient and was not nonspecifically affected
by sepsis, drugs, trauma, surgical intervention, and anesthesia. In order to do this we selected a method described by Merton19 and modified by Edwards~’° and used to study muscle fatigue. It consisted of measuring the contraction of the adductor pollicis muscle in response to an electrical stimulus of the ulnar nerve at the wrist. When the nerve is stimulated at the above site with unidirectional square wave pulses lasting only 50-70 psec at a range of frequencies from 10 to 50 Hz, there is a progressive increase in force with a maximum attained at 50 Hz. This is called the force-frequency curve. In addition, if the nerve is stimulated at 20 Hz for 2 sec and then the stimulus is switched off, the muscle relaxes and the rate of relaxation can be measured. Finally, if the stimulus at 20 Hz is continued, any loss of power represents fatigue of an objective nature (not due to voluntary relaxation). By studying two pure models of human starvation and refeeding, namely the starving obese subject and the anorexic patient being refed, we showed that starvation, causes the ratio of the force at 10 Hz/50-100 Hz to
double and the relaxation rate to slow from a mean of about 10% of maximal force lost/10 msec to ~ ~0-6 ~~. In addition, we showed the development of fatigue. Refeeding corrected these changes prior to gain in body nitrogen.:21~:25 In other studies Lenmarken et aF6 found the relaxation rate to be a good index of the nutritional status. More importantly, Zeiderman and McMahon’ have shown that in a group of preoperative surgical patients the combination of an abnormal force-frequency curve and slow relaxation rate was the most specific and sensitive predictor of nutritional associated complications when compared with other parameters of nutritional status such as hand-grip strength, arm muscle circumference, and albumin and transferrin levels. CLINICAL ASSESSMENT BASED ON A SUBJECTIVE GLOBAL ASSESSMENT OF THE PATIENT.
The above considerations have indicated that nutritional assessment using laboratory data alone, except for muscle function, fail to identify patients at risk of nutritionally mediated complications. This failure is in part due to the wide range of normal values (anthropometry) and in part due to the fact that disease and inactivity alone can result in the same effects on these laboratorygenerated parameters as malnutrition. Therefore, we decided to determine whether a global clinical assessment, which we later called subjective global assessment (SGA), would identify patients likely to develop nutritionally mediated complications. 12,13,27,28
Theoretical Basis of SGA The basis for this assessment’8 was to determine first whether there was a true restriction of food intake and/ or digestion and absorption and second whether there were associated effects on function and body composition of an acute nature. We hypothesized that if food intake had improved, there was low risk even though the patient was wasted and underweight. The data which showed that refeeding anorexics restored muscle function prior to body nitrogen supports these concepts.22
Methodology The assessment is made by obtaining the following six patient’s condition and scoring them as
features of the
FiG. 1.
Septic complication
Downloaded from pen.sagepub.com at St Petersburg State University on December 27, 2013
rate
(9c of patients) in SGA grades A
to
C.
195S
specificities of the carious clinical and objective The superiority of clinical judgment has been confirmed by Otto et at ’21 who showed that clinical judgment was superior to measurement of DCH in predicting postoperative infection. It should be recognized that clinical judgment is based on a composite of’ criteria ties and
parameters. 1,3
based on an estimate of (1) past nutritional intake: (2) disease process and operation affecting future intake of nutrients: (3) catabolic effect of the disease affecting the patient; and (4) current physical state in relation to weight loss, wasting, functional status, body fat loss, and other signs of malnutrition such as glossitis, edema, skin
rashes, and neuropathy. FIG. 2. Likelihood ratio for all grades A to C.
complications in relation
to
SGA
weight change (loss in past 6 months: 0 or >10%; change in past 2 weeks: increase, stable, or decrease [If there is recent weight gain then previous loss is not considered in the assessment.]); (2) dietary intake (no change or suboptimal intake, liquid diet, or hypocaloric fluids or starvation; (3) gastrointestinal symptoms for >2 weeks (nil, anorexia and nausea, vomiting, diarrhea) ; (4) functional capacity (normal, suboptimal work, ambulatory, or bedridden); (5) stress (nil, minimal, or high); and (6) physical signs (loss of subcutaneous fat over the triceps and/or chest; Muscle wasting of the deltoids, temporals, and/or quadriceps; fluid retention: edema, ascites; mucosal lesions: glossitis, skin rash suggestive of deficiency). follows: (1)
