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ORIGINAL ARTICLE

Acta Medica Indonesiana - The Indonesian Journal of Internal Medicine

Abdominal Circumference in Relation to Body Weight Gain/Loss in Patients on Chronic Hemodialysis

Parlindungan SiregarDepartment of Internal Medicine, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia.

Correspondence mail: Division of Nephrology and Hypertension, Department of Internal Medicine, Faculty of Medicine, Universitas Indonesia. Jl. Salemba 6, Jakarta 10430, Indonesia. email: sparlindungan@yahoo.com.

ABstRAkTujuan: untuk menentukan hubungan yang konstan antara perubahan lingkar perut (dalam satuan

sentimeter) dan berat badan (dalam satuan Kilogram) pada pasien penyakit ginjal kronik (PGK) yang menjalani hemodialisis kronik. Metode: penelitian ini merupakan studi analitik eksperimental yang dilakukan pada pasien PGK yang menjalani hemodialisis dengan menggunakan desain penelitian sebelum dan sesudah perlakuan (before and after treatment) di Unit Dialisis Rumah Sakit Cipto Mangunkusumo. Sampel penelitian dipilih secara berurutan (consecutive sampling). Pengukuran berat badan dan lingkar perut dilakukan pada hari yang sama sebelum dan setelah sesi hemodialisis. Pengukuran diulang pada hari yang berbeda untuk 104 subyek agar mencapai jumlah sampel target sebesar 676 subyek. Pemeriksaan kadar albumin juga dilakukan untuk subjek-subjek tersebut. Hasil: terdapat korelasi yang kuat (r=0,838) dan bermakna (p=0,000) antara berat badan rata-rata dan lingkar perut sebelum dan sesudah hemodialisis. Pada kalkulasi regresi untuk antara berat badan rata-rata sebelum maupun sesudah hemodialisis (X) dan lingkar perut rata-rata sebelum maupun sesudah hemodialisis (Y), didapatkan rumus regresi sebagai berikut: Y=34,94 + 0,84 X. Tidak terdapat korelasi yang bermakna antara kadar albumin (3,93 ±0,40 g/dL) dan lingkar perut sebelum hemodialisis, lingkar perut setelah hemodialisis, serta lingkar perut rata-rata sebelum dan sesudah hemodialisis. Kesimpulan: perkiraan perubahan berat badan pada pasien PGK yang menjalani hemodialisis dapat ditentukan dengan pengukuran lingkar perut sebelum dan sesudah hemodialisis.

Kata kunci: lingkar perut, pertambahan berat badan, hemodialisis.

ABstRACtAim: to determine a constant relationship between changes in abdominal circumference (in centimeter)

and body weight (in kilogram) in chronic kidney disease (CKD) patients undergoing chronic hemodialysis. Methods: experimental-analytical study in patients with CKD on hemodialysis, using before and after treatment design at the Dialysis Unit of Cipto Mangunkusumo Hospital, Jakarta. The sample were selected consecutively. Weighing and abdominal circumference measurements were done at the time of before and after hemodialysis session on the same day. Repeated measurements were performed on different days in 104 subjects to achieve the target sample size of 676. Serum albumin level were also measured on the patients. Results: there was a strong (r=0.838) and significant (p=0.000) correlation between mean body weight and mean abdominal circumferences before and after hemodialysis. In the calculation of the regression between the mean body weight before and after hemodialysis (X) with a mean abdominal circumference before and after hemodialysis (Y), regression formula: Y=34.94 + 0.84 X was obtained. There was no significant correlation between serum albumin levels (3.93±0.40 g/dL) and abdominal circumference before hemodialysis, abdominal circumference after hemodialysis, and the mean abdominal circumference before and after hemodialysis. Conclusion: prediction of weight changes in patients

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INtRODUCtIONWeighing procedure before and after

hemodialysis session of a patient is an essential procedure performed on every patient with chronic kidney disease (CKD).1-4 The importance of this weighing is to assess the status of the extracellular fluid volume. Increased intradialytic weight gain is independently associated with decreased survival of chronic kidney disease (CKD) patients treated with chronic hemodialysis.5 Extracellular fluid volume status in hemodialysis patients can be classified in three circumstances: 1) dry weight, 2) heavier than dry weight, and 3) lighter than dry weight. A more than 5% weight gain from the dry weight is categorized into excessive extracellular fluid volume status or hypervolemia, while the opposite condition classified into reduced extracellular fluid volume status or hypovolemia. Increase in extracellular fluid volume status can easily occur in patients with terminal stage of kidney disease due to a very low ability of the kidneys to excrete water.

Extracellular compartment is divided into two subcompartments which are intravascular and interstisium. Both subcompartments are bounded by a permeable membrane. The movement of water between this two subcompartments occur because of the difference in hydrostatic pressure or osmotic pressure difference between them.6-9 Increased hydrostatic pressure will cause the water move from the intravascular to interstitium under the skin, lung, and intraperitoneal, causing peripheral edema, pulmonary edema (central), and ascites consecutively.10-14

On the other hand, increased in intraperitoneal fluid or ascites is regularly less monitored in patients with CKD on hemodialysis. In the daily clinical practice, measurement of waist circumference can be used as a parameter that indicates the increase or decrease in volume of intraperitoneal fluid. Based on this condition, a study on chronic hemodialysis patients in order

to determine the relationship between increased extracellular fluid with abdominal circumference was conducted.

The objective of this study was to determine a constant relationship between changes in abdominal circumference (in centimeter) and body weight (in Kilogram) in CKD patients underwent chronic hemodialysis. A certain increment in weight, measured through the abdominal circumference, was specifically dedicated to CKD patients on hemodialysis who cannot perform weighing by themselves due to paralysis or other handicaps. Results of this study can be used by all hemodialysis units, particullarly those in terminal kidney disease undergoing hemodialysis, who are not able to do the weighing by themselves.

MEtHODsAn interventional study was conducted in

CKD patients underwent hemodialysis in Unit of Dialysis Division of Kidney-Hypertension Department of Internal Medicine in Faculty of Medicine Universitas Indonesia, using before and after treatment design. Sample size determination was preceded by doing a pilot study on 35 chronic hemodialysis patients in Dialysis unit of Siloam Hospital Lippo-Village Tangerang. A total of 676 sample was determined after the calculation was done. The patients chosen, were selected again in accordance with inclusion and exclusion criteria. The inclusion criteria are as follows: patients who has been undergoing hemodialysis for over than 3 months, capable of lying down in supine position without pillow, and weighing of body weight can be done alone by themselves. Those who were not willing to participate in research were excluded. For those who were selected, weighing was done before and after hemodialysis session using the same scale and clothes. After subjects laid down in supine position without pillow, measurement of abdominal circumference were performed

with CKD on chronic hemodialysis, can be measured through the abdominal circumference measurement before and after hemodialysis.

Key words: abdominal circumference, weight gain, hemodialysis.

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using gauges made of plastic through the navel of patients (gauges fit snugly against the skin of the patient). Measurement of body weight and abdominal circumferences were performed repeatedly on the same subjects in every different sessions until the desired sample size were reached. Serum albumin level examinations were also done on the subjects. Statistical analysis using paired T-test was performed in normal distribution, while Wilcoxon test was done when distribution of data was not normal in order to test the differences between weight and abdominal circumferences of the subjects before and after hemodialysis sessions. Pearson’s correlation test was performed if the distribution of data was normal, while Spearman’s correlative test was done in the opposite condition in order to test the correlation between body weight and abdominal circumference before and after hemodialysis sessions. Coefficient of regression was also assessed in order to calculate the predictor value of changes between abdominal circumferences and body weight. All of theres analysis were done using SPSS statistics-17 program. The Ethics Committee of the Faculty of Medicine, University of Indonesia had given the approval for this study.

REsULtsThere was a significant difference (p=0.000)

between weights before hemodialysis (median 59.95 Kg, ranged between 39-91.5 Kg), and body weight after hemodialysis (median 56.80 Kg, ranged between 38.10-87.50 Kg). A significant difference was also found (p=0.000) between abdominal circumference before hemodialysis (median 88 cm, ranged between 62-112 cm) and abdominal circumference after hemodialysis (median 85 cm, ranged between 57-110 cm). Furthermore, there was a strong and significant correlation between the weights before hemodialysis and abdominal circumference before hemodialysis (r=0.845; p=0.000). There was also a strong and significant correlation between body weight after hemodialysis and abdominal circumference after hemodialysis (r=0.839; p=0.000). In addition, there was a strong and significant correlation between the mean body weight before-after hemodialysis and a mean abdominal circumference before-after hemodialysis (r=0.848; p=0.000). In the calculation of the regression between body weight before hemodialysis (X) and abdominal circumference before hemodialysis (Y) a regression formula: Y = 35.120 + 0.825

body weight

Ab

do

min

al circu

mfe

ren

ce

Y = 35.120 + 0.825 X

Figure 1. Regression curve between body weight and abdominal circumference before hemodialysis.

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X was obtained (Figure 1), and the R Square was equivalent to 0.703. In the calculation of regression between body weight after hemodialysis (X) and abdominal circumference after hemodialysis (Y) a regression formula: Y = 34.032 + 0.854 X was obtained (Figure 2), and the R Square was equivalent to 0.694. Furthermore, In the calculation of the regression between the

mean body weight before-after hemodialysis (X) and mean abdominal circumference before-after hemodialysis (Y) a regression formula: Y = 34.94 + 0.84 X was obtained (Figure 3), the R Square was equivalent to 0.703. The mean albumin level of all patients were 3.93±0.40 g/dL. There was no significant correlation between serum albumin level and abdominal circumference

body weight

Ab

do

min

al circu

mfe

ren

ce

Y = 34.032 + 0.854 X

Figure 2. Regression curve between body weight and abdominal circumference after hemodialysis.

body weight

Ab

do

min

al circu

mfe

ren

ce

Y = 34.94 + 0.84 X

Figure 3. Regression curve between mean body weight and abdominal circumference before-after hemodialysis.

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before hemodialysis, abdominal circumference after hemodialysis, and mean abdominal circumference before-after hemodialysis.

DIsCUssIONIn this investigation, there was a strong and

significant correlation between body weight and abdominal circumference before-after hemodialysis. Similarly, there was a strong and significant correlation between mean body weight before-after hemodialysis and mean abdominal circumference before-after hemodialysis. In analysis that was performed on the calculation of regression between body weight before hemodialysis (X) and abdominal circumference before hemodialysis (Y), a 70.3% regression model from function of Y can be be explained by factor of X (R Square = 0.703). 33.587 ≤ β0 ≤ 38.652 was The interval confidence of 95%, 0 784 ≤ β1 ≤ 0.865 and also found, showed a considerable coefficient of regression. In the calculation of regression from ANOVA table, a value of F = 1593.395> (Fα,1,n-2 = F0,05.1.674 = 3,01), that revealed the regression model of Y = 36.120 + 0.825 X was relatively satisfying.

Furthermore, analysis that was performed on the calculation of regression between body weight after hemodialysis (X) and abdominal circumference after hemodialysis (Y), a 69.4% regression model from function of Y can be be explained by factor of X (R Square = 0.694). The interval confidence of 95%, 0.811 ≤ β1 ≤ 0.896 and 31.482 ≤ β0 ≤ 36.582, showed a significant coefficient of regression.

In the calculation of regression from ANOVA table, a value of F = 1526.684> (Fα,1,n-2 = F0,05.1.674 = 3,01), which showed the regression model of Y = 34.032 + 0.854 X was relatively satisfying as well. In addition, analysis that was done on calculation of regression between mean of body weight before-after hemodialysis (X) and mean abdominal circumference before-after hemodialysis (Y), a 70.3% regression model from function of Y can be be explained by factor of X (R Square = 0.703). Interval confidence of 95%, 0.812 ≤ β1 ≤ 0.870 and 33.164 ≤ β0 ≤ 36.721, showed a significant coefficient of regression. In the calculation of regression from ANOVA table, a value of F = 3195.766>

(Fα,1,n-2 = F0,05.1.1350 = 1.04), which shows the regression model of Y = 35 + 0,84 X was relatively satisfying.15

From the results of regression analysis above, it was revealed that the body weight of patients before and after hemodialysis could be predicted by their abdominal circumference. For example, there are patients who could not be weighed before a hemodialysis session because of certain conditions, then an abdominal circumference measurement is performed with the results of 70 cm. Thus, with the regression formula between mean of body weight before-after hemodialysis and mean abdominal circumference before-after hemodialysis (Y = 34.94 + 0.84 X), the body weight of this patient before hemodialysis could be predicted, which is 42 kg. If the targeted body weight after hemodialysis is 40 kg (X), then the expected abdominal circumference based on this regression formula such is 68.54 cm (Y), in which the waist circumference will be reduced about 1.46 cm. With this method, the prediction of weight loss after hemodialysis could be determined by measuring the abdominal circumference of the patient. In addition, albumin levels of 102 patients in this study it turned out to be relatively normal, which are 3.93±0.40 g/dL. However, there was no significant correlation between albumin levels and abdominal circumference before and after hemodialysis, as well as mean abdominal circumference before-after hemodialysis. Thus, there was no influence of serum albumin levels towards the changes in abdominal circumferences in this study.

CONCLUsIONThere is a strong correlation between the

mean body weight and abdominal circumference of patients on chronic hemodialysis.

There is a significant causal relationship between body weight and abdominal circumference of patients on chronic hemodialysis.

Prediction of the weight changes before-after hemodialysis in chronic hemodialysis patients can be performed through the abdominal circumference measurement.

In this study, the serum albumin levels had no influence on the changes of abdominal circumferences in chronic hemodialysis patients.

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