***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Higher body mass index ( BMI ) appears paradoxically associated with better outcomes in patients with chronic kidney disease . Whereas higher BMI reflects both increased visceral and subcutaneous fat and /or muscle mass , a combined assessment of BMI and waist circumference may enable differentiation of visceral adiposity from muscle and /or nonvisceral fat mass . We examined the association of BMI and waist circumference with all‐cause mortality in a prospect i ve cohort of 993 kidney transplant recipients . Associations were examined in Cox models with adjustment for demographic and comorbid conditions and for inflammatory markers . Unadjusted death hazard ratios ( 95%CI ) associated with one st and ard deviation higher BMI and waist circumference were 0.94 ( 0.78 , 1.13 ) , p = 0.5 and 1.20 ( 1.00 , 1.45 ) , p = 0.05 , respectively . Higher BMI was associated with lower mortality after adjustment for waist circumference ( 0.48 [ 0.34 , 0.69 ] , p < 0.001 ) , and higher waist circumference was more strongly associated with higher mortality after adjustment for BMI ( 2.18 [ 1.55–3.08 ] , p < 0.001 ) . The associations of waist circumference with mortality remained significant after additional multivariable adjustments . Higher BMI and waist circumference display opposite associations with mortality in kidney transplant recipients . Waist circumference appears to be a better prognostic marker for obesity than BMI BACKGROUND Low body mass index ( BMI ) is associated with greater mortality in patients on dialysis therapy .  This relationship is less well characterized in patients with chronic kidney disease ( CKD ) who are not yet on dialysis therapy .  STUDY DESIGN Historic prospect i ve cohort . SETTING & PARTICIPANTS 521 male US veterans with CKD ( age , 68.8 + /- 10.4 years ; 21.3 % black ; estimated glomerular filtration rate , 37.5 + /- 16.8 mL/min/1.73 m(2 ) [ 0.62 + /- 0.28 mL/s/1.73 m(2 ) ] ) at a single medical center . PREDICTOR BMI . OUTCOMES & MEASUREMENTS Associations with all-cause mortality were explored in fixed-covariate and time-dependent Cox models and sequentially adjusted for demographic characteristics ( age and race ) , case-mix ( comorbidity index , smoking , blood pressure , estimated glomerular filtration rate , and medication use ) , and surrogates of malnutrition and inflammation ( serum albumin , cholesterol , and bicarbonate levels ; white blood cell count ; percentage of lymphocytes ; and hemoglobin level ) . RESULTS Patients were followed up for up to 5.5 years , and the mortality rate was 128.3 deaths/1,000 patient-years ( 95 % confidence interval [ CI ] , 110.5 to 149.0 ) . Higher BMI was associated with lower mortality in the fixed-covariate Cox models , including the fully adjusted model ( adjusted hazard ratios for mortality in the group with BMI in 10th to 50th , 50th to 90th , and > 90th versus < 10th percentiles , 0.75 [ 95 % CI , 0.46 to 1.22 ] , 0.56 [ 95 % CI , 0.33 to 0.94 ] , and 0.39 [ 95 % CI , 0.17 to 0.87 ] ; P(trend ) = 0.005 ) . Associations were similar in a time-dependent Cox model ( P(trend ) = 0.008 in the fully adjusted model ) . LIMITATIONS Results may not be generalizable . CONCLUSIONS Lower BMI is associated with greater mortality in patients with CKD not yet on dialysis therapy .  Adjustment for case-mix and surrogate markers of malnutrition and inflammation attenuated , but did not reverse , this relationship BACKGROUND AND OBJECTIVES Many studies show that obesity in dialysis patients is not strongly associated with mortality but not whether this modest association is constant over age . This study investigated the extent to which the relation of body mass index ( BMI ) and mortality differs between younger and older dialysis patients . DESIGN , SETTING , PARTICIPANTS , & MEASUREMENTS Adult dialysis patients were prospect ively followed from their first dialysis treatment for 7 years or until death or transplantation .  Patients were stratified by age ( < 65 or ≥65 years ) and baseline BMI ( < 20 , 20 - 24 [ reference ] , 25 - 29 , and ≥30 kg/m(2 ) ) . RESULTS The study sample included 984 patients younger than 65 years and 765 patients 65 years or older ; cumulative survival proportions at end of follow-up were 50 % and 16 % . Age-st and ardized mortality rate was 1.7 times higher in obese younger patients than those with normal BMI , corresponding to an excess rate of 5.2 deaths/100 patient-years . Mortality rates were almost equal between obese older patients and those with normal BMI . Excess rates of younger and older patients with low compared with normal BMI were 8.7 and 1.1 deaths/100 patient-years . After adjustment for age , sex , smoking , comorbidity , and treatment modality , hazard ratios by increasing BMI were 2.00 , 1 , 0.95 , and 1.57 for younger patients and 1.07 , 1 , 0.88 , and 0.91 for older patients , implying that obesity is a 1.7-fold ( 95 % confidence interval , 1.1- to 2.9-fold ) stronger risk factor in younger than older patients . CONCLUSIONS In contrast to older dialysis patients , younger patients with low or very high BMI had a substantially elevated risk for death BACKGROUND Obesity management requires underst and ing the mortality risks associated with different adiposity measures . STUDY DESIGN Prospect i ve cohort . SETTING & PARTICIPANTS 5,805 adults with body mass index ( BMI ) ≥18.5 kg/m(2 ) and stages 1 - 4 chronic kidney disease , defined as a spot urine albumin-creatinine ratio ≥30 mg/g and /or estimated glomerular filtration rate < 60 mL/min/1.73 m(2 ) , enrolled in the Reasons for Geographic and Racial Differences in Stroke ( REGARDS ) Study . PREDICTOR BMI categorized as 18.5 - 24.9 , 25.0 - 29.9 , 30.0 - 34.9 , 35.0 - 39.9 , and ≥40 kg/m(2 ) and waist circumference categorized as < 80 , 80 - 87.9 , 88 - 97.9 , 98 - 107.9 , and ≥108 cm in women and < 94 , 94 - 101.9 , 102 - 111.9 , 112 - 121.9 , and ≥122 cm in men . OUTCOMES All-cause mortality . MEASUREMENTS BMI and waist circumference were measured using a st and ardized protocol during the home visit . RESULTS 686 ( 11.8 % ) deaths occurred during a median follow-up of 4 years . Compared with the referent BMI category of 25 - 29.9 kg/m(2 ) , HRs for mortality were 1.27 ( 95 % CI , 0.96 - 1.69 ) for BMI < 25 kg/m(2 ) and 0.84 ( 95 % CI , 0.62 - 1.13 ) , 0.81 ( 95 % CI , 0.52 - 1.26 ) , and 0.95 ( 95 % CI , 0.54 - 1.65 ) for BMI categories 30 - 34.9 , 35 - 39.9 , and ≥40 kg/m(2 ) after adjustment for covariates including waist circumference , respectively . In contrast , after adjustment for covariates including BMI , higher mortality rates were noted for all waist circumference categories compared with the referent ( < 80 cm in women and < 94 cm in men ) , with HRs of 1.04 ( 95 % CI , 0.77 - 1.41 ) for waist circumference of 80 - 87.9 cm in women and 94 - 101.9 cm in men , 1.29 ( 95 % CI , 0.92 - 1.81 ) for waist circumference of 88 - 97.9 cm in women and 102 - 111.9 cm in men , 1.72 ( 95 % CI , 1.12 - 2.62 ) for waist circumference of 98 - 107.9 cm in women and 112 - 121.9 cm in men , and 2.09 ( 95 % CI , 1.26 - 3.46 ) for waist circumference ≥108 cm in women and ≥122 cm in men . LIMITATIONS BMI and waist circumference measured at baseline only . CONCLUSIONS Waist circumference should be considered in conjunction with BMI when assessing mortality risk associated with obesity in adults with chronic kidney disease BACKGROUND Mortality risk for people with chronic kidney disease is substantially greater than that for the general population , increasing to a 7-fold greater risk for those on dialysis therapy . Higher body mass index , generally due to higher energy intake , appears protective for people on dialysis therapy , but the relationship between energy intake and survival in those with reduced kidney function is unknown . STUDY DESIGN Prospect i ve cohort study with a median follow-up of 14.5 ( IQR , 11.2 - 15.2 ) years . SETTING & PARTICIPANTS Blue Mountains Area , west of Sydney , Australia . Participants in the general community enrolled in the Blue Mountains Eye Study ( n = 2,664 ) who underwent a detailed interview , food frequency question naire , and physical examination including body weight , height , blood pressure , and laboratory tests .  PREDICTORS Relative energy intake , food components ( carbohydrates , total sugars , fat , protein , and water ) , and estimated glomerular filtration rate ( eGFR ) . Relative energy intake was dichotomized at 100 % , and eGFR , at 60 mL/min/1.73 m(2 ) . OUTCOMES All-cause and cardiovascular mortality . MEASUREMENTS All-cause and cardiovascular mortality using unadjusted and adjusted Cox proportional regression models . RESULTS 949 people  died during follow-up , 318 of cardiovascular events . In people with eGFR<60 mL/min/1.73 m(2 ) ( n = 852 ) , there was an increased risk of all-cause mortality ( HR , 1.48 ; P = 0.03 ) , but no increased risk of cardiovascular mortality ( HR , 1.59 ; P = 0.1 ) among those with higher relative energy intake compared with those with lower relative energy intake . Increasing intake of carbohydrates ( HR per 100g/d , 1.50 ; P = 0.04 ) and total sugars ( HR per 100g/d , 1.62 ; P = 0.03 ) was associated significantly with increased risk of cardiovascular mortality . LIMITATIONS Under-reporting of energy intake , baseline laboratory and food intake values only , white population . CONCLUSIONS Increasing relative energy intake was associated with increased all-cause mortality in patients with eGFR<60 mL/min/1.73 m(2 ) . This effect may be mediated by increasing total sugars intake on subsequent cardiovascular events BACKGROUND Loss of residual renal function has a profound effect on the survival of  peritoneal dialysis patients . Less is known of the impact of peritoneal function . The purpose of this study was to investigate the influence of solute transport on clinical outcome in CAPD patients . METHODS Two hundred and ten consecutive patients commencing CAPD since 1990 were enrolled into a single centre prospect i ve longitudinal observational study of urea , protein , and peritoneal kinetics . On entry , and at 6-monthly intervals , estimations were made of weight , body mass index ( BMI ) , plasma albumin , Kt/V , residual renal function ( RRF ) , NPCR , low-molecular-weight solute transport ( D/Pcreat ) , and peritoneal protein losses . All patients were censored in 1996 , regardless of treatment modality . RESULTS During the 6-year follow up period ( median 22 months ) there were 51 deaths , and the actuarial survival was 58 % at 5 years . Urea , protein and peritoneal kinetics varied with time on dialysis : as anticipated there was a reduction in Kt/V , attributable to loss of RRF , whereas plasma albumin was stable for the first 2 years of treatment 
    Output:
    
There was no apparent association between obesity and mortality in transplanted patients or those on peritoneal dialysis .
Conclusions : Being obese may be protective for all‐cause mortality in the predialysis and hemodialysis population s , while being underweight suggests increased risk , but not in transplant recipients