Vol. 10: e6-e9, March 2005
BRIEF REPORT
Caloric requirement for refeeding inpatients with anorexia nervosa: The contribution of anxiety exercise, and cigarette smoking C.L. Birmingham, J. Hlynsky, L. Whiteside, and J. Geller Eating Disorders Program, St. Paul’s Hospital, University of British Columbia, Vancouver, Canada
ABSTRACT. Background: Refeeding inpatients with anorexia nervosa (AN) is costly, stressful, and can precipitate the refeeding syndrome. Caloric intake is usually increased gradually from a low starting point until a steady weight gain is achieved. There is no reliable equation that predicts the number of calories required for a weight gain. It was our clinical suspicion that anxiety, exercise, and cigarette smoking might increase the caloric need for refeeding. Method: We conducted an observational cohort study of 17 females with AN admitted to an inpatient eating disorder unit for refeeding. We estimated the energy intake by observation, the caloric expenditure due to exercise with a triaxial accelerometer, the number of cigarettes smoked by history, and the anxiety by the Beck Anxiety Inventory (BAI). Results: Neither anxiety, exercise, or cigarette smoking predicted the caloric requirement for refeeding, individually or in combination. Discussion: Our data suggest that the caloric requirement for weight gain during refeeding is not predicted by the patient’s anxiety, exercise or smoking habits. The standard methods of estimating caloric requirements for refeeding remain indirect calorimetry and previous history. (Eating Weight Disord. 10: e6-e9, 2005). ©2005, Editrice Kurtis
INTRODUCTION
Key words: Feeding, calories, exercise, anxiety. Corresponence to: Prof. C. Laird Birmingham, Eating Disorder Program, St. Paul’s Hospital, 1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6 E-mail:
[email protected] Received: November 11, 2003 Accepted: June 18, 2004 e6
Weight restoration is essential to recovery in AN. Hospitalization for refeeding can be costly, lengthy, anxiety provoking, damage rapport, reduce motivation for recovery and precipitate the refeeding syndrome. One factor that limits the potential benefit of refeeding is the inability to predict the caloric requirement for weight gain. Some centres measure the metabolic rate by indirect calorimetry. This is costly, requires special expertise, may interrupt or delay meals, and may cause the patient to feel claustrophobic. Alternatively, if the caloric intake of previous admissions is known, this is often a good indicator of the present requirement. If it is unknown, dietitians usually begin with less than 1200 kcal a day and gradually increase the caloric intake over several weeks until a satisfactory rate of weight gain is achieved. Studies have demonstrated that the Harris-Benedict Equation alone is not reliable in estimating the calories required
for refeeding in AN (1-3). We were previously unsuccessful at developing a predictive equation incorporating age, height, weight, percent body fat, and leptin levels (4). Our clinical impression is that patients who suffer from extreme anxiety need more calories in order to gain weight. As well, occult exercise and cigarette smoking are known to increase caloric expenditure. We hypothesized that taking into account anxiety, cigarette smoking, and exercise might help predict the caloric intake necessary for refeeding.
METHODS Setting and subjects Subjects were recruited from the inpatient eating disorder ward of a university teaching hospital. Ethical approval was not necessary because the data collection and investigations, including cigarette smoking status, anxiety estimation, and the use of the triaxial accelerometer are
Estimating caloric requirements
routine. Exclusion factors were: pregnancy, diabetes mellitus, and untreated hypothyroidism. All subjects had the diagnosis of AN made using DSM-IV criteria. Registered psychiatric nurses, psychiatrists, psychologists, internists, dietitians, an occupational therapist, a recreation therapist, a social worker, and a pharmacist provide care to the patients. Clinical rounds are made three times weekly and the diet is usually adjusted twice a week as necessary. All feeding was by meal support alone. Medications commonly prescribed are: zoplicone or trazadone as hypnotics, lorazepam or clonazepam as anxiolytics, and loxapine for self-injurious behavior or extreme anxiety.
Statistics The caloric requirement for weight gain was modelled by adjusting the Harris-Benedict Equation (for females) for anxiety, exercise, and cigarette smoking. The Harris-Benedict (HB) was derived in normal subjects at rest (8): REE = 655.1 + 9.6 (wt kg) + 1.9 (ht cm) - 4.7 (age) We compared the caloric intake at the end of their admission with the step-wise adjustment of the HB using our estimates of the calories expended by exercise, cigarette smoking and anxiety. All statistics were calculated using SPSS for Windows v. 11.5.
RESULTS Measures Weight and height were recorded on a balance beam scale with stadiometer on admission, weekly, and at discharge. The BMI was calculated as weight in kilograms divided by height in meters squared. The number of cigarettes smoked per day was obtained by history on the second inpatient day. All cigarette smoking on the ward takes place in a “smoking chamber”. Daily caloric expenditure in kilocalories from smoking was derived by multiplying the average number of cigarettes smoked per day during the first two days of admission by ten as suggested by Hoffstetter et al. (9). The caloric expenditure from exercise was recorded using a triaxial accelerometer (RT3, Stayhealthy.com) over a 48-hour period within the first 72 hours of admission. The accelerometer was worn 24 hours a day (except during bathing) (5-7). Anxiety was measured by the Beck Anxiety Inventory (Psychological Questionnaires). Daily caloric expenditure from anxiety was estimated from the score of the Beck Anxiety Inventory administered within 48 hours of admission. Subjects who demonstrated an anxiety score of 26 or greater are described as being “severe” on the Beck Anxiety Inventory. We were unable to find a method of converting the Beck Anxiety Inventory score into caloric expenditure. For simplicity, we estimated the caloric expenditure as equal to the anxiety score. The caloric intake of the meal plan just before discharge was used as the observed caloric requirement for refeeding. Every portion of every meal is specially ordered, observed, and any deviations recorded. The dietitian converts this into caloric intake. All patients are monitored during meals and for one hour after each meal activity.
Twenty-seven females aged 19 to 50 entered the study (Table 1). Ten were withdrawn because of premature discharge from hospital, intermittent unavailability of the triaxial accelerometer, or loss of data. Seventeen patients had complete data. Of these patients, ten had anorexia nervosa, restrictive type (ANR) and seven had anorexia nervosa, bingepurge type (AN-BP). The duration of illness ranged from one to twenty-three years with a mean of nine ± six years. The body mass index (BMI) on admission was 18.01±4.06 and after refeeding 18.91±3.66. Two patients had an extremely high muscle mass causing their BMI’s to be high. Table 1 shows the changes in BMI during the inpatient three-week admission for each subject. Caloric expenditure from exercise measured by the triaxial accelerometer ranged from 114.0 to 501.0 kcal per day with a mean value of 251.1±137.3 kcal per day. Five of the seventeen subjects were smokers. A mean of eleven cigarettes per day were smoked by these five. There was no clinically significant correlation between energy requirements for weight gain and anxiety, exercise or cigarette smoking (Table 2).
DISCUSSION The caloric requirement for weight gain varies greatly in patients with anorexia nervosa. It sometimes takes three weeks before the food plan is large enough for weight gain to occur. Traditionally, the caloric need is estimated by the previous history of caloric need for weight gain. If there is no previous history, the dietitian starts with a low number of calories and increases gradually. We know that exercise burns calories and that cigarette smoking causEating Weight Disord., Vol. 10: N. 1- 2005
e7
C.L. Birmingham, J. Hlynsky, L. Whiteside, et al.
TABLE 1 Patient data. Sex
Age (years)
Diagnosis
Anxiety score
Exercise calories
Cigarette calories
Observed calories ingested
BMI 1 (kg/m2)
BMI 2 (kg/m2)
BMI difference (kg/m2)
F
19
AN-R
50
177
0
2400
17.02
20.55
3.54
F
25
AN-R,B/P
50
488
150
1900
18.74
18.63
-0.11
F
34
AN-R,B/P
45
114
0
2300
11.62
11.69
0.07
F
25
AN-B/P
43
480
0
1600
18.78
18.52
-0.26
F
29
AN-R
39
211
100
1600
24.3
25.51
1.21
F
22
AN-R
31
193
50
1900
19.14
19.84
0.70
F
39
AN-B/P
31
210
0
1900
20.41
20.02
-0.40
F
40
AN-B/P
29
142
0
2000
13.71
14.42
0.71
F
26
AN-R
29
463
0
2100
15.56
16.93
1.38
F
36
AN-B/P
24
149
0
1800
17.87
18.67
0.80
F
25
AN-R
24
501
150
1900
25.68
25.13
-0.55
F
20
AN-B/P
22
197
0
1700
23.82
23.67
-0.15
F
20
AN-R
18
191
0
1900
17.85
18.51
0.66
F
36
AN-R
17
258
0
1800
19.23
20.08
0.85
F
23
AN-R
16
193
100
3500
12.5
17.89
5.39
F
27
AN-R
14
118
0
3300
13.16
14.06
0.90
F
29
AN-R
7
182
0
1900
16.77
17.42
0.65
F=female subjects; AN=anorexia nervosa; R=restrictive type; B/P = binge purge type; Anxiety scores are from the Beck Anxiety Inventory; Exercise Calories=calories expended by exercise measured by the triaxial accelerometer Cigarette Calories calculated by multiplying number of cigarettes smoked per day times 10 Ingested Calories (observed) refer to the calories prescribed by the dietitian to result in weight gain
TABLE 2 Correlational data.
Observed calories
HB, Anxiety
HB, Exercise
HB, Cigarettes
HB, Anxiety, exercise
HB, Anxiety, cigarettes
HB, Exercise, cigarettes
HB, Anxiety, exercise, cigarettes
-0.605*
-0.569*
-0.472
-0.576*
-0.487*
-0.495*
-0.501*
*Significant at the 0.05 level
es energy expenditure (9-11). It has previously been reported that the caloric requirement of patients with great anxiety also seems to be increased (12, 13). An earlier study by Kaye et al. (11) stressed the importance of reducing exercise in hospitalized patients in order to reduce the number of calories necessary for refeeding. Nevertheless, our findings suggest that taking into account anxiety, exercise, and cigarette smoking does not improve our estimate of caloric need for refeeding. Our study has a number of limitations. The subject population who may have smoked more cigarettes e8
Eating Weight Disord., Vol. 10: N. 1- 2005
or retained less food, the small sample size, and the indirect nature of the estimates of caloric expenditure from cigarette smoking and anxiety limit this conclusion. Previous studies have demonstrated that the triaxial accelerometer provides a reliable measurement of daily activity levels. However, the triaxial accelerometer is not watertight and therefore is removed during showers, when occult activity can occur. It may be necessary to correlate putative factors to measurements of metabolic rate performed repeatedly over the day (e.g. after showers ) to learn more.
Estimating caloric requirements
REFERENCES 1. Rodriguez G., Moreno L.A., Sarria A., Fleta J., Bueno M.: Resting energy expenditure in children and adolescents: agreement between calorimetry and prediction equations. Clin Nutr., 21, 255-260, 2002. 2. Marra M., Polito A., De Filippo E., Cuzzolaro M., Ciarapica D., Contaldo F., Scalfi L.: Are the general equations to predict BMR applicable to patients with anorexia nervosa? Eat. Weight Disord., 7, 53-59, 2002. 3. Wahrlich V., Anjos L.A.: Validation of predictive equations of basal metabolic rate of women living in Southern Brazil. Rev. Saude Publica, 35, 39-45, 2001. 4. Pauly R.P., Lear S.A., Hastings F.C., Birmingham C.L.: Resting energy expenditure and plasma leptin levels in anorexia nervosa during acute refeeding. Int. J. Eat. Disord., 28, 231-234, 2000. 5. Fehling P.C., Smith D.L., Warner S.E., Dalsky G.P.: Comparison of accelerometers with oxygen consumption in older adults during exercise. Med. Sci. Sports Exerc., 31, 171-175, 1999. 6. Fulton J.E., Masse L.C., Tortolero S.R., Watson K.B., Heesch K.C., Kohl H.W., Blair S.N., Caspersen C.J.: Field evaluation of energy expenditure from continu-
7.
8.
9.
10.
11.
12. 13.
ous and intermittent walking in women. Med. Sci. Sports Exerc., 33, 163-170, 2001. Leenders N., Sherman W.M., Nagaraja H.N.: Comparisons of four methods of estimating physical activity in adult women. Med. Sci. Sports Exerc., 32, 1320-1326, 2000. MacDonald A., Hildebrandt L.: Comparison of formulaic equations to determine energy expenditure in the critically ill patient. Nutrition, 19, 233-239, 2003. Hofstetter A., Schutz Y., Jequier E., Wahren J.: Increased 24-hour energy expenditure in cigarette smokers. N. Engl. J. Med., 314, 79-82, 1986. Brkljacic B., Korsic M., Delic D.: The effect of smoking on the metabolic rate and heart rate. Lijec Vjesn., 110, 252-254, 1988. Kaye W.H., Gwirtsman H.E., Obarzanek E., George D.T.: Relative importance of calorie intake needed to gain weight and level of physical activity in anorexia nervosa. Am. J. Clin. Nutr., 47, 989-994, 1988. Blaza S.E., Garrow J.S.: The effect of anxiety on metabolic rate. Proc. Nutr. Soc., 39, 13A, 1980. Schmidt W.D., O'Connor P.J., Cochrane J.B., Cantwell M.: Resting metabolic rate is influenced by anxiety in college men. J. Appl. Physiol., 80, 638-642, 1996.
Eating Weight Disord., Vol. 10: N. 1- 2005
e9
