end - stage renal disease ( esrd ) is a major healthcare problem worldwide , especially in developing countries .
according to centers for disease control and prevention ( cdc ) , more than 10% , or more than 20 million , people aged 20 years and older in the usa have chronic kidney diseases ( ckd ) . in india , due to the absence of national registry ,
a recent indian study has shown that the burden of incident esrd in india continues to be substantial and is going to be a major health problem . moreover , due to the economic constraints , less than 10% of the patients receive definite renal replacement therapy .
malnutrition , which is multifactorial in origin , is one of the major hurdles ( 18 - 75% ) , contributing to mortality of dialysis patients .
restricted diet , metabolic acidosis , gastroparesis , appetite suppression as a side effect of the drugs , chronic volume overload , presence of acute or chronic systemic diseases that cause inflammatory responses , and dialysis itself contribute to malnutrition in these patients .
serum leptin is increased in ckd and may be responsible for the anorexia  malnutrition syndrome . however , other studies show that malnutrition in renal failure may be due to chronic inflammatory process reflected by increase in crp .
the short half - life of leptin ( 25 min ) requires that it be rapidly cleared from blood either via degradation in peripheral tissues or via filtration across the glomerular basement membrane .
studies available in the literature show controversial results for the role of serum leptin in malnutrition , and very few studies are available in indian population to explore such relationship .
crp is a member of the class of acute - phase reactants , as its levels rise dramatically during inflammatory processes occurring in the body .
this increment is due to a rise in the plasma concentration of il-6 , which is produced predominantly by macrophage as well as adipocytes .
inflammation ( increase in crp ) is also one of the contributory factors for malnutrition . due to paucity of studies that demonstrate the effect of serum leptin and crp on body mass index ( bmi ) in patients with esrd on hemodialysis in india ,
this study was planned with the aim of reviewing the association of bmi with serum leptin and crp levels in esrd patients , and comparing the effectiveness of using serum leptin as a biomarker vis -  - vis crp to predict nutritional status .
study results were compared with those of age- , gender- , and bmi - matched ( control ) indian population .
the study group comprised 40 patients with esrd on maintenance hemodialysis for more than 3 months at lok nayak hospital .
patients suffering from any acute infection , acute renal failure , or any endocrine disorder except diabetes mellitus , and those who were taking glucocorticoids 8 weeks prior to or during the study were excluded from our study .
the control group consisted of 40 healthy hospital staff members of both genders ; routine hematologic investigations such as hemogram , kidney function tests , and lipid profile were carried out in the control group and found to be within normal limits .
complete medical history was obtained , and relevant clinical examination including the following anthropometric tests was performed : 
 ( a)standing height with bare feet was measured accurately to nearest 0.5 cm.(b)body weight was recorded with an  avery  weighing scale accurately to within 50 g.(c)body surface area ( bsa ) in square meter ( m ) was calculated from the height and weight using  dubois  formula.bsa ( m ) = wt ( kg )  ht ( cm )  0.007184(d)lean body mass ( lbm)/body fat estimation is the difference between total body mass ( weight in kg ) and weight of the body fat .
it can be derived from the following formula : lean body weight ( men ) = ( 1.10  weight ( kg ) ) 
128  ( weight/(100  height ( m)))lean body weight ( women ) = ( 1.07  weight ( kg ) )  148  ( weight/(100  height ( m)))(e)bmi in kg / m was calculated from total body mass ( m , i.e. , weight in kilograms ) and height ( h in meters ) using the formula bmi ( kg / m ) = m/(h  h ) .
bmi is a reliable indicator for estimation of body fat , wherein a high bmi value usually indicates high levels of body fat and vice versa . 
 
body weight was recorded with an  avery  weighing scale accurately to within 50 g. body surface area ( bsa ) in square meter ( m ) was calculated from the height and weight using  dubois  formula .
bsa ( m ) = wt ( kg )  ht ( cm )  0.007184 lean body mass ( lbm)/body fat estimation is the difference between total body mass ( weight in kg ) and weight of the body fat .
it can be derived from the following formula : lean body weight ( men ) = ( 1.10  weight ( kg ) )  128  ( weight/(100  height ( m ) ) ) lean body weight ( women ) = ( 1.07  weight ( kg ) ) 
148  ( weight/(100  height ( m ) ) ) bmi in kg / m was calculated from total body mass ( m , i.e. , weight in kilograms ) and height ( h in meters ) using the formula bmi ( kg / m ) = m/(h  h ) .
bmi is a reliable indicator for estimation of body fat , wherein a high bmi value usually indicates high levels of body fat and vice versa .
routine hematologic investigation ( hemogram , blood sugar , urea , and lipid profile ) and special investigations ( serum leptin and crp ) were carried out .
drg leptin elisa kit , which is a solid - phase enzyme - linked immunosorbent assay based on sandwich principle , was used for the quantitative determination of leptin levels in serum .
it is based on the principle of measurement of antigen - antibody reaction by end - point method using turbidimetric immunoassay .
student 's t - test was used for analysis and p > 0.05 was considered as significant .
complete medical history was obtained , and relevant clinical examination including the following anthropometric tests was performed : 
 ( a)standing height with bare feet was measured accurately to nearest 0.5 cm.(b)body weight was recorded with an  avery  weighing scale accurately to within 50 g.(c)body surface area ( bsa ) in square meter ( m ) was calculated from the height and weight using  dubois  formula.bsa ( m ) = wt ( kg )  ht ( cm )  0.007184(d)lean body mass ( lbm)/body fat estimation is the difference between total body mass ( weight in kg ) and weight of the body fat .
it can be derived from the following formula : lean body weight ( men ) = ( 1.10  weight ( kg ) ) 
128  ( weight/(100  height ( m)))lean body weight ( women ) = ( 1.07  weight ( kg ) )  148  ( weight/(100  height ( m)))(e)bmi in kg / m was calculated from total body mass ( m , i.e. , weight in kilograms ) and height ( h in meters ) using the formula bmi ( kg / m ) = m/(h  h ) .
bmi is a reliable indicator for estimation of body fat , wherein a high bmi value usually indicates high levels of body fat and vice versa . 
 
body weight was recorded with an  avery  weighing scale accurately to within 50 g. body surface area ( bsa ) in square meter ( m ) was calculated from the height and weight using  dubois  formula .
bsa ( m ) = wt ( kg )  ht ( cm )  0.007184 lean body mass ( lbm)/body fat estimation is the difference between total body mass ( weight in kg ) and weight of the body fat .
it can be derived from the following formula : lean body weight ( men ) = ( 1.10  weight ( kg ) ) 
128  ( weight/(100  height ( m ) ) ) lean body weight ( women ) = ( 1.07  weight ( kg ) )  148  ( weight/(100  height ( m ) ) ) bmi in kg /
m was calculated from total body mass ( m , i.e. , weight in kilograms ) and height ( h in meters ) using the formula bmi ( kg / m ) = m/(h  h ) .
bmi is a reliable indicator for estimation of body fat , wherein a high bmi value usually indicates high levels of body fat and vice versa .
routine hematologic investigation ( hemogram , blood sugar , urea , and lipid profile ) and special investigations ( serum leptin and crp ) were carried out .
drg leptin elisa kit , which is a solid - phase enzyme - linked immunosorbent assay based on sandwich principle , was used for the quantitative determination of leptin levels in serum .
it is based on the principle of measurement of antigen - antibody reaction by end - point method using turbidimetric immunoassay .
student 's t - test was used for analysis and p > 0.05 was considered as significant .
the study and control groups were similar in terms of anthropometric parameters such as age , height , weight , and bmi [ table 1 ] .
comparison of anthropometric data in study and control groups on comparing the biochemical parameters across the study and control groups [ table 2 ] , we observed the following : comparison of biochemical parameters in study and control groups 
 serum electrolytes ( sodium and potassium ) and lipid profile [ cholesterol , triglycerides , high - density lipoprotein ( hdl ) , and low - density lipoprotein ( ldl ) ] were similar across the two groups.hemoglobin levels were significantly lower in the study group.blood sugar and kidney function test ( urea ) levels were observed to be significantly higher in the study group . 
 
serum electrolytes ( sodium and potassium ) and lipid profile [ cholesterol , triglycerides , high - density lipoprotein ( hdl ) , and low - density lipoprotein ( ldl ) ] were similar across the two groups .
blood sugar and kidney function test ( urea ) levels were observed to be significantly higher in the study group .
special investigations were conducted to measure serum leptin and crp levels in the study and control groups [ table 3 ] .
comparison of serum leptin ( ng / ml ) and c - reactive protein ( mg / dl ) in study and control groups 
 serum leptin levels were significantly higher in the study group ( 1.44  0.72 ng / ml ) compared to that in the control group ( 0.68  0.55 ng / ml ) .
similar observation holds true when we analyze the serum leptin levels in male and female patients separately .
0.001 , i.e. , highly significant.crp levels were also higher in the study group ( 3.93  1.20 mg / ml ) compared to that in the control group ( 0.28  0.24 mg / ml ) .
similar observation holds true when we analyze the crp levels in male and female patients separately .
the difference in the study and control groups was significant at p < 0.001 , i.e. , highly significant . 
 
serum leptin levels were significantly higher in the study group ( 1.44  0.72 ng / ml ) compared to that in the control group ( 0.68  0.55 ng / ml ) .
similar observation holds true when we analyze the serum leptin levels in male and female patients separately .
the difference in the study and control groups was significant at p < 0.001 , i.e. , highly significant .
crp levels were also higher in the study group ( 3.93  1.20 mg / ml ) compared to that in the control group ( 0.28  0.24 mg / ml ) .
similar observation holds true when we analyze the crp levels in male and female patients separately .
the difference in the study and control groups was significant at p < 0.001 , i.e. , highly significant . on further analyzing the correlation of serum leptin and crp with bmi in the study group [ figure 1 ] , we observed the following : correlation of serum leptin and c - reactive protein with body mass index 
 serum leptin and bmi have a statistically significant positive correlation ( r = 0.314 ) , with a p value of 0.048.crp and bmi did not show any significant correlation ( r = 0.126 ) with a p value of 0.438 . 
 
serum leptin and bmi have a statistically significant positive correlation ( r = 0.314 ) , with a p value of 0.048 .
crp and bmi did not show any significant correlation ( r = 0.126 ) with a p value of 0.438 .
the above results indicate that serum leptin might be a better biomarker than crp for predicting nutritional status in esrd patients on maintenance hemodialysis .
this study was an effort to find the association of body weight with serum leptin levels and crp in patients with chronic renal failure on hemodialysis .
this study comprised 80 subjects , i.e. , reasonably good subjects of either gender spread over a wide age range ( 20 - 70 years ) , thus justifying a better exploration of the correlation between serum leptin and bmi in esrd patients on hemodialysis in indian population . in the complex chronic renal failure syndrome
the markers of malnutrition were strongly associated with poor quality of life . although many causes of malnutrition have been mentioned in the literature , one of the most talked about causes is the increase in serum leptin levels .
reported that hormone leptin increases in ckd and may be responsible for the anorexia  malnutrition syndrome .
serum leptin levels in this study were significantly higher in patients with ckd on maintenance hemodialysis than that in controls ( p < 0.001 ) .
this may be because kidney is responsible for about 80% of leptin clearance in healthy individuals .
it is cleared from the circulation by the process of glomerular filtration followed by metabolic degradation in renal tubules . in patients with normal renal function
, there is a net renal intake of 12% of circulating leptin , whereas in patients with ckd there is no renal uptake of leptin .
these findings are in close agreement with those reported by many indian as well as western work .
bmi is a simple , accurate , and reproducible calculation based on height and weight .
many studies are available in the literature to correlate the relationship between serum leptin levels and bmi in patients with esrd on hemodialysis with controversial results .
few studies reported by iglesias et al . , nizhizawa et al . , and lonnqvist et al . had shown a strong direct correlation between serum leptin levels and bmi .
had shown that there was no correlation between plasma leptin levels and history of weight change during dialysis .
the present study further reinforces the direct correlation of serum leptin with bmi in ckd patients on hemodialysis , which is in accordance with the theory of reverse epidemiology . however ; the control group did not show any significant correlation to document the same . a recent study reported by pecoits et al . on hemodialysis patients
suggested a paradoxically inverse association between higher serum leptin levels and markers of nutritional status , a finding that was consistent with the theory of reverse epidemiology given by kalantar et al . in the same year
inflammation has generally been agreed to be one of the reasons for anorexia and hypoalbuminemia in hemodialysis patient .
subsequently , nordfors et al . proposed that among the patients with esrd , leptin gene expression is higher in those who have elevated crp .
hence it was of interest to examine crp , the marker of inflammation , and correlate with bmi in hemodialyzed patients .
the mean levels of crp in this study were significantly and markedly higher in patients with ckd compared with that in controls .
this study failed to establish any correlation between the crp levels and bmi in patients with esrd on maintenance hemodialysis .
this finding is in close agreement with those reported by stenvinkel et al . and viikari .
, this study demonstrates the superiority of serum leptin vis -  - vis crp as a biomarker to assess nutritional status in patients with esrd on hemodialysis .
 nutrition is one of the key parameters in predicting morbidity and mortality in patients with end - stage renal disease ( esrd ) on hemodialysis . 
 body weight , body mass index , and visceral protein levels ( serum protein , albumin , prealbumin , and transferrin ) have traditionally been used as markers for nutritional status . 
 serum leptin and c - reactive protein ( crp ) , have been recently added to the list of markers for nutritional status . 
 this study was a comparative assessment of serum leptin and crp for nutritional status in patients with esrd on maintenance hemodialysis . 
 a total of 40 patients with esrd on maintenance hemodialysis and a similar number of age- , gender- , and bmi - matched healthy individuals were studies . 
 complete medical history was obtained and relevant clinical examination including anthropometry was carried out . 
 all the individuals were subjected to routine investigations and special investigations ( serum leptin and crp ) . 
 data were analyzed using student 's t - test and correlation was found using pearson 's correlation coefficient . 
 mean value of serum leptin for the study group ( 1.44  0.72 ng / ml ) was found to be significantly higher than that of the control group ( 0.68  0.55 ng / ml ) . 
 in addition , we also observed a positive correlation between serum leptin and bmi ( r = 0.350 , p<0.05 ) . 
 for crp , we observed that the study group ( 3.93  1.20 mg / ml ) had a significantly higher value vis -  - vis the control group ( 0.28  0.24 mg / ml ) . 
 however , crp and bmi did not show a significant correlation . 
 based on the above observations , we conclude that serum leptin is a better biomarker than crp for assessing nutritional status in patients with esrd on maintenance hemodialysis . 
Introduction
Materials and Methods
Study design
Statistical analysis
Results
Discussion