Comparison of anthropometric equations for estimation of total body water in peritoneal dialysis patients.

BACKGROUND: Several formulae exist for estimating total body water (TBW). We aimed to assess their validity in peritoneal dialysis patients by comparison with TBW estimated by deuterium oxide dilution (TBW(D)). METHODS: We compared the equations of Chertow (TBW(Cher)), Chumlea (TBW(Chum)), Hume and Weyers (TBW(HW)), Johansson (TBW(J)), Lee (TBW(L)), Watson (TBW(W)) and TBW as 58% of body weight (TBW(0.58Wt)) with TBW(D) in 31 peritoneal dialysis (PD) patients and 32 controls. Estimates were compared with TBW(D) using Bland and Altman comparison. Extracellular water (ECW) was also estimated by sodium bromide dilution. RESULTS: In PD patients, mean TBW(D) was 35.04 (SD 7.84) l. Estimates were greater for TBW(Cher), TBW(Chum), TBW(HW), TBW(J) and TBW(0.58Wt). Mean TBW(L) and TBW(W) did not differ from TBW(D). Ninety-five percent limits of agreement (LOA) compared with TBW(D) (as a percentage of the mean) were similar for all of the different equations in PD patients (between +/-15.4 and +/-17.3%) except TBW(0.58Wt), which was far greater (+/-26.4%). In controls, mean TBW(D) was 37.03 (SD 6.63) l. Estimates were greater for TBW(Cher), TBW(Chum), TBW(HW), TBW(J) and TBW(0.58Wt). Mean TBW(L) and TBW(W) did not differ from TBW(D). Ninety-five percent LOA compared with TBW(D) (as a percentage of the mean) were similar for all equations in the controls, and closer than in PD patients (between +/-9.1 and +/-11.5%) except TBW(0.58Wt), which was again far greater than the other equations (+/-28.1%). TBW(HW) - TBW(D) correlated with mean TBW (r=-0.412, P<0.05 in PD and r=-0.383, P<0.05 in controls). TBW(W) - TBW(D) (r=-0.539, P<0.005) correlated with mean TBW in PD. TBW(0.58Wt) - TBW(D) correlated with body mass index (BMI) (r=0.624, P<0.0001 in PD and r=0.829, P<0.0001 in controls) and ECW/TBW (r=0.406, P<0.05 in PD and r=0.411, P<0.02 in controls). CONCLUSIONS: Predictive equations were less accurate in PD than controls. TBW(0.58Wt) was most inaccurate, with systematic overestimation of TBW with increasing BMI and ECW/TBW. There were no differences in LOA with TBW(D) for the other equations within each group.     

Determination of total body water in uraemic patients by bioelectrical impedance

The measurement of total body water by bioeiectrical impedancein a group of renal patients was evaluated against the tritiumdilution method. The effect of haemodialysis and the presenceof peritoneal dialysate on the impedance were also investigated.The correlation between the two methods is r = 0.90 with a residualstandard deviation of 3.7. The standard devi ation of the differencesbetween the two methods against the means was 3.66 which meansthat total body water (TBW) estimated by the bioelectrical impedance(BEI) method may be 6.181 (X ± 2 SD) above or 8.381 belowthe ³H₂O method. The BEI method overestimated the actual weightloss after haemodialysis (3.87±1.71 versus 2.43±1.81)but underestimated the volume of peritoneal dialysate in situThe BEI method would not be appropriate for use in assessingtotal body water and monitoring acute volume changes in patientswith renal failure who are on strict fluid restriction.     

Measurement of total body water with deuterium oxide in renal diseases

Total body water was measured by means of dilution technic with 99.8% deuterium oxide administration in normal subjects (controls), nephrotic (NS) patients with or without edema, and in longterm hemodialysis (HD) patients. Lean body mass (LBM) was calculated from height, body weight, and waist girth. Body fluid was evaluated according to the TBW/LBM ratio in HD patients. Effect of volume of body fluid on blood pressure was also investigated. Relationship among cardio-thoracic ratio (CTR), standard body weight (SW), and TBW were examined. SWTBW calculated from TBW and LBM, and SWCTR estimated mainly from CTR, blood pressure, were compared. The total body water to body weight ratios (TBW/BW) in controls, NS, and HD patients were 61.2 +/- 1.2%, 71.3 +/- 3.7% (with edema), 60.9 +/- 6.4% (without edema), 64.5 +/- 6.9% (pre-HD), 62.6 +/- 6.6% (post-HD) respectively. The mean TBW/BW of NS patients with edema was significantly greater than those of control, NS patients without edema, and post-HD patients. The TBM/LBM value above 0.78 was suggestive of overhydrated state in HD patients. The mean TBW/LBM in HD patients was 0.757, which was greater than that of controls. Hypotension during HD was seemingly induced by excess ultrafiltration regardless of the value of TBW/LBM. No relationship among CTR, SW, and TBW was observed in HD patients, but the mean TBW/LBM of patients with the CTR exceeding 55% was 0.786, which suggested as overhydrated state. It is useful to determine TBW/BW and TBW/LBM in order to evaluate of volume changes in body fluid of longterm HD patients.     

Perioperative monitoring of total body water by bio-electrical impedance in children undergoing open heart surgery

Knowledge of the changes in total body water (TBW) following cardiac surgery (OHS) in children would be of value in fluid therapy and in researching the causes and management of capillary leak. We have validated a bioelectrical impedance technique (BEI) for non-invasive estimation of TBW in children after OHS. We report the use of this method in a longitudinal study. Twenty patients (mean age 4.7 years +/- 3.5 (SD), mean weight (WT) 16.2 kg +/- 1 kg) undergoing a variety of complex OHS procedures were studied from 1 day preoperatively to 4 days postoperatively. Anaesthetic and basic bypass (CPB) techniques were uniform. Six patients underwent CPB at less than 20 degrees C, 10 at 20 degrees - 25 degrees C and 4 at 26 degrees - 33 degrees C. TBW (BEI), core (ctemp) and peripheral (ptemp) temperatures and fluid balance (TFB) were recorded at frequent intervals. TBW (by BEI) rose (P less than 0.001) following CPB in all patients from 62% +/- 9% (SD) body weight preoperatively to 73% +/- 13% in the ICU (an increase of 11% +/- 5%). TBW remained significantly elevated until the 3rd postoperative day. Multivariate analysis (MVA) confirmed that TBW was significantly related to TFB, but not to ctemp or ptemp. MVA also revealed smaller patient size (height and weight), younger age and longer CPB time as incremental risk factors for the rise in TBW. Conclusions: (1) BEI permits the non-invasive study of TBW in children after OHS, when TBW variation may be considerable. (2) The smaller the child and the longer the CPB, the greater the rise in TBW. (3) The technique should be a valuable tool in researching the major water fluxes associated with CPB in children.     

Quantifying acute changes in volume and nutritional status during haemodialysis using bioimpedance analysis

Aim: To determine the precision of multi‐frequency bioimpedance analysis (MFBIA) in quantifying acute changes in volume and nutritional status during haemodialysis, in patients with end‐stage renal disease (ESRD). Methods: Using whole‐body MFBIA, we prospectively studied changes in total body water (TBW), extracellular volume (ECV), intracellular volume (ICV), lean body mass (LBM), body cell mass (BCM) and fat mass (FM), pre‐ and post‐haemodialysis and tested the agreement of volume changes with corresponding acute weight change and ultrafiltration volume (UF) using Bland‐Altman analysis. Results: Forty‐four prevalent and 17 incident haemodialysis patients were studied (median age 55 years, 56% males). MFBIA‐derived TBW, ECV, ICV, LBM and BCM were significantly reduced after haemodialysis (P < 0.001), but FM remained constant. TBW change estimated weight change with mean bias of ?0.52 L, with 56/61 (91.8%) data points within limits of agreement (?2.74 L, 1.69 L). TBW change estimated UF with mean bias of ?0.62 L, with 55/61 (90.2%) data points within limits of agreement (?2.68 L, 1.43 L). ECV change underestimated weight change and UF with mean bias of ?1.17 L and ?1.27 L respectively. Similarly, ICV change underestimated both clinical measures with corresponding mean bias of ?1.34 L and ?1.44 L. Comparing incidents versus prevalent haemodialysis patients, TBW change estimated weight change with smaller mean bias (?0.10 L vs?0.69 L, respectively) and narrower limits of agreement. Conclusion: Multi‐frequency bioimpedance analysis‐derived TBW change has the best agreement with acute clinical volume change during haemodialysis compared to ECV or ICV change alone, but overall degree of precision remains poor. Nutritional assessment using LBM and BCM measurements is significantly confounded by hydration status.     

Increased risk of tooth loss is related to bone loss at the whole body,hip, and spine

Increased systemic bone loss may be a risk factor for tooth loss by contributing to the resorption of toothsupporting alveolar bone. Concurrent longitudinal associations between tooth loss and bone loss at the whole body, femoral neck, and spine were examined in 189 healthy, white, dentate, postmenopausal women who participated in three intervention trials conducted within a 7-year period. None of the subjects was taking estrogen. Bone mineral density (BMD) was measured by dual photon or dual energy X-ray absorptiometry. Teeth were counted at baseline; number and timing of teeth lost over the observation period were assessed by questionnaire. All analyses were controlled for years since menopause, body mass index, number of teeth at baseline, smoking status, and the assigned treatment during each study. These interventions were calcium (Ca) or placebo (P) in Study I, vitamin D+Ca or P+Ca in Study II, and 1 of 2 doses of vitamin D+Ca in Study III. Age at baseline (mean±SD) was 59±6 years and the number of teeth remaining was 23±7. Women who lost teeth during the 7-year follow-up (n=45) experienced less favorable changes in BMD at all sites compared with 144 women who lost no teeth (whole body mean±SE, -0.35±0.08%/year versus -0.11±0.05, P<0.01; femoral neck -0.48±0.38%/year versus -0.14±0.35, P<0.05; and spine, +0.05±0.21%/year versus +0.45±0.16, P<0.05). For each 1%/year decrement in BMD, relative risks (and 95% CI) of losing a tooth were significantly elevated at the whole body (RR=relative risks, CI=confidence interval) (RR=4.83, CI=1.72–13.52, n=180), femoral neck (1.50, 1.02 to 2.22, n=189), and spine (1.45, 1.00 to 2.11, n=167). These results provide support for a role of systemic bone loss in the development of tooth loss among postmenopausal women.     

IgG glycation and function during continuous ambulatory peritoneal dialysis

IgG in dialysate may have an important role in anti-infection mechanisms during continuous ambulatory peritoneal dialysis (CAPD). As Fc fragment oligosaccharidic chains are crucial for IgG effector functions, we have tested the hypothesis that IgG glycation might occur during CAPD and modify IgG properties. Purified normal IgG was incubated with glucose solutions of different concentrations and pH. Separation of glycated IgG was performed by affinity chromatography. Complement activation (C3c deposition) and phagocytosis by polymorphonuclear leucocytes (PMN) were studied in vitro using Staphylococcus aureus Wood (STAW) as antigen. In addition, we compared the percentages of glycated IgG in IgG purified from sera and dialysates of 12 CAPD patients. The percentage of glycated IgG after in vitro incubation of normal IgG with glucose solutions was directly proportional to glucose concentrations, incubation time and pH. Glycated IgG anti-STAW induced a higher C3c deposition than non-glycated IgG anti-STAW (C3c/IgG (mean±SD) 0.96±0.06 vs 0.79±0.08; P=0.027). PMN phagocytosis was not affected by IgG glycation. The percentages of glycated IgG in dialysates of CAPD patients were greater than those in corresponding sera (5.38±2.36% vs 4.56±2.47% P=0.006). It is concluded that IgG glycation may take place in the peritoneal cavity during CAPD and lead to enhanced complement activation. This could explain the high degree of complement activation previously described in dialysate of CAPD patients and might theoretically result in a reduction of complement factors available in dialysate for adequate anti-infection mechanisms.     

Low-density lipoprotein subfraction profiles in chronic renal failure

Background: Small low-density lipoprotein (LDL) particle size, a newly recognized risk factor for cardiovascular disease in the general population, is frequently associated with hypertriglyceridaemia, the predominant plasma lipid abnormality present in uraemia. Methods: Plasma lipids and LDL subfraction profiles were examined in 33 non-dialysed patients with chronic renal failure (predial), 40 patients on continuous ambulatory peritoneal dialysis (CAPD), 42 haemodialysis patients (HD), 47 renal transplant recipients (RTR), and 44 controls. LDL subfractions separated by gel electrophoresis were scored by densitometric analysis (higher scores indicate profiles comprising smaller particles). Results: All groups with renal failure had significantly elevated (mean±SD) LDL scores (predial 1.36±0.6, CAPD 1.71±0.9, HD 1.68±0.9, RTR 1.92±0.8 vs control 0.87±0.4, all P<0.001), this being the only lipid abnormality detected in the predialysis patients. In CAPD and HD patients, LDL scores were associated with serum triglyceride (r=0.81, P<0.0001 and r=0.70, P<0.01 respectively), cholesterol (r=0.55, P<0.001 and r=0.49, P<0.01) and HDL-cholesterol (r=-0.43, P<0.01 and r=-0.51, P<0.01), whilst no such relationship was seen in the predialysis and RTR groups, suggesting that other factors were important. Conclusions: The presence of small LDL particles appears to be an early and unexplained feature of the uraemic dyslipidaemia. This abnormality persists after renal transplantation and may represent an important atherogenic risk factor. Key words: LD subfractions; renal failure; transplants      

A study of association between lean body mass and serum insulin-like growth factor-1 in continuous ambulatory peritoneal dialysis patients

Malnutrition is one of the major issues associated with high mortality and morbidity in chronic dialysis patients. Several methods to evaluate the nutritional status of these patients have been attempted for example anthropometric measurement and biochemical parameters. Recently, it was reported that insulin-like growth factor-1 (IGF-1) has been valuable for estimating nutritional status. In this study, we measured lean body mass (LBM) by dual energy X-ray absorptiometry (DXA), IGF-1 and other biochemical parameters in 35 patients on CAPD. Two years later, the second measurement of LBM was performed, and we assessed the percent changes of LBM and biochemical parameters. There was negative correlation between the percent changes of LBM and the duration of CAPD. In patients treated with CAPD for less than 36 months (group I) LBM increased, however, it decreased significantly in those treated for more than 36 months (group II). On the other hand, in group I there was a positive correlation between the percent changes of LBM and IGF-1. In group II there was no correlation between the percent changes of LBM and any other biochemical parameters. It could be concluded that IGF-1 is one of the predisposing factors for improving LBM of patients on CAPD for a limited duration.     

Relationship between different body size indicators and hernia development in CAPD patients

AIMS: A small body size may increase the risk for hernia development in patients on continuous ambulatory peritoneal dialysis (CAPD). The present study investigates whether there is a relationship between body size and hernia development in CAPD patients. MATERIAL AND METHODS: The records of 78 patients on CAPD were reviewed retrospectively. Body mass index (BMI), body surface area (BSA) and total body water (TBW) were calculated in all patients. Correlations between different body size indicators (BMI, BSA and TBW) and hernia development were assessed using analysis of covariance in which we adjusted for sex. RESULTS: A total of 14 patients (17.9%) with no physical evidence of hernia before catheter insertion developed hernias. Body size was significantly lower in CAPD patients with hernias than those without hernias when adjusted for sex. CONCLUSIONS: We conclude that patients with small body size tend to have an increased risk for hernia development. A simple estimation of patients' height, weight, body surface area and total body water would be helpful to predict development of hernias or other complications related to increased intraperitoneal pressure in CAPD patients.     

Measuring total body water in peritoneal dialysis patients using an ethanol dilution technique

Measuring total body water in peritoneal dialysis patients using an ethanol dilution technique. BACKGROUND: The accuracy with which total body water (TBW) is estimated is a direct determinant of the reliability of Kt/V urea measurements in peritoneal dialysis (PD) patients. Ethanol dilution has been previously shown to be a reliable measure of TBW. Advances in breath alcohol technology make this a feasible clinical tool. METHODS: We gave 19 fasting chronic PD patients 0.3 g/kg of ethanol (EtOH) orally on two separate occasions. Breath alcohol concentrations (BrACs), determined by dual-beam infrared analysis, were recorded at baseline and periodically thereafter until BrACs were less than 0.01%. The TBW was then determined by standard pharmacokinetic techniques. RESULTS: TBW measurements were reproducible, with a mean between-run difference of -0.004 liter/kg (95% limits of agreement -0.040 to 0. 032 by Bland-Altman). The Watson equations tended to underestimate TBW, with a mean difference (EtOH - Watson) of +3.0 liters (SD 4.0 liters, P = 0.004) and a mean absolute difference of 4.1 liters (SD 2.7 liters, range -4.4 to 9.5 liters). Kt/V was calculated from dialysate and urine collection, using V as determined from TBW estimates from EtOH and Watson. The mean Kt/V(EtOH) was 2.31 (SD 0. 50) compared with 2.46 (SD 0.52) using Watson. The mean absolute difference between the two Kt/V estimates was 0.26 (SD 0.20, range -0.87 to 0.57), with Kt/V overestimated by Watson in 14 patients. EtOH was well tolerated, and the procedure was completed in about four hours. CONCLUSIONS: Measuring V by the BrAC technique does not require blood sampling, is reliable, and is reproducible. It is a potentially useful method for a periodic determination of volume that may allow for more accurate Kt/V measurement in PD patients.     

Continuous Ambulatory Peritoneal Dialysis (CAPD) Adequacy Influences Serum Free Carnitine Level

Objective: An evaluation of serum free carnitine level in CAPD patients in relation to dietary intake, nutritional status and CAPD adequacy and duration. Study design: Food diaries, nutritional (total body mass, lean body mass, serum level of proteins, carnitine, cholesterol) and adequacy (Kt/V, PCR, tCcr, EN) parameters were obtained in 23 CAPD patients. Results: Normal carnitine level (41.8±6.7 µmol/l) was found in 17 patients being on CAPD through 11.1±9.6 months, whereas in 6 persons treated with CAPD through 9.7±4.1 months carnitine level was 25.4±5.7 µmol/l. Significant differences between low and normal carnitine groups were in tCcr (82.7±16.7 v. 65.9±13.2 l/wk/1.73 m² BSA), effluent volume (10.9±0.8 v. 9.9±1.5 l/day), effluent glucose concentration (729=167 v. 530±220 mg/dl) and serum globulin level (22.6±6.4 v. 29.3±4.4 g/l). Significant correlation coefficients (for n=23) were found between serum carnitine level and effluent volume (r=–0.509) or plasma globulin level (r=+0.522). Conclusion: Patients with higher CAPD adequacy show lower serum free carnitine levels and this is related to higher effluent volumes.     

The impact of residual renal function and total body water volume on achieving adequate dialysis in CAPD.

AIMS: The objective is to evaluate the impact of residual renal function (RRF) and total body water (TBW) on achieving adequate dialysis. METHODS: Sixty three CAPD patients performing four 2 liter exchanges daily were evaluated for RRF, total weekly Kt/V (TWKt/V), total weekly creatinine clearance (TWCC) and TBW. RESULTS: In patients with residual renal function (N = 41), TWKt/V and TWCC were 2.2 +/- 0.8 and 77.4 +/- 24.5 L, respectively. In patients without RRF (N = 22), TWKt/V was 1.6 +/- 0.4 and TWCC 42.6 +/- 9.2 L. TBW correlated negatively with TWKt/V in the group without RRF (r = -0.75, P<0.001). CONCLUSION: It is not possible for larger patients without RRF treated with CAPD (2L x 4 exchanges) to achieve the acceptable targets for TWKt/V and TWCC due to TBW.     

Is Lean Body Mass Decreased after Obesity Treatment by Adjustable Gastric Banding?

Background There is concern that surgically-induced weight loss in obese subjects is associated with a disproportionate decrease in lean body mass (LBM) and in skeletal muscle mass (SMM), a major constituent of LBM. To address this issue, 1) we measured total and regional body composition following gastric banding in a group of obese subjects, and 2) we compared these data to those of a non-surgical control group of similar age and body size. Methods Body composition was assessed by dualenergy X-ray absorptiometry (DEXA) before and after laparoscopic adjustable silicone gastric banding (LAGB) in 32 women (after 1 year: age 43.7 ± 8.4 years, BMI 36.4 ± 5.9 kg/m², mean ± SD), and in 117 control women (age 44.5 ± 7.5 years; BMI 36.7 ± 5.5 kg/m²) referred for non-surgical weight management, prior to weight loss. SMM was estimated using a published equation based on LBM of the extremities (appendicular LBM). Results 1 year after LAGB, body weight loss (−23.7 ± 11.6 kg, P < 10⁻⁶) was mainly due to decreased fat mass (−21.2 ± 11.2 kg, P < 10⁻⁶), and total LBM was modestly, although significantly, decreased (−2.1 ± 4.2 kg, P = 0.01). Appendicular LBM (−0.7 ± 2.7 kg) and total SMM (−0.9 ± 3.0 kg) were not significantly modified. None of the body composition variables was significantly decreased in weight-reduced subjects compared to the control group, especially appendicular LBM and total SMM. Conclusions Results provide no evidence for a decrease in appendicular LBM and total SMM with weight loss following LAGB. Follow-up of these obese patients revealed a very favorable pattern of change in total and regional body composition, with preservation of muscle mass.     

Anthropometric and body composition assessment in dialysis patients

Anthropometric and body composition assessments provide important information about the nutritional status of dialysis patients. Anthropometric measurements describe body size, fatness, and leanness in dialysis patients and have been collected in the Modification of Diet in Renal Disease (MDRD) and HEMO studies. Dialysis patients present special problems for anthropometry, including decreased functional status and increased comorbidity, that challenge nutrition assessment methodology. Recumbent anthropometric techniques are recommended and stature is estimated from knee height. Measures of weight, stature, calf circumference, arm circumference, and triceps and subscapular skinfolds have recently been reported for dialysis patients, who tend to be shorter, lighter, and have less adipose tissue than healthy persons of the same age. The HEMO study anthropometric data provide a clinical reference for assessing the nutritional status of dialysis patients. The most common body composition methods used with dialysis patients are dual energy X-ray absorptiometry (DEXA), bioelectrical impedance, total body water (TBW), and prediction equations, but they are not recommended for assessment of predialysis patients, as estimates are best obtained postdialysis. The TBW volume used in calculating the dose of dialysis has commonly been predicted from the limited, out-of-date equations of Watson, based on nonrepresentative samples. New prediction equations are available for white, black, and Mexican American children and adults. Watson's data are not representative of the TBW of U.S. men and women. The greater TBW in non-Hispanic black men and women and Mexican American women reflects the greater levels of obesity in the U.S. population.     

The influence of peritoneal dialysis and the use of subcutaneous and intraperitoneal insulin on glucose metabolism and serum lipids in type 1 diabetic patients

Background. Intraperitoneally administered insulin is regarded as the most physiological replacement therapy, leading to lower peripheral insulin concentrations and equal or better glycaemic control than subcutaneous insulin. This two-part study was undertaken to evaluate the effect of CAPD, as well as the use of subcutaneous vs. intraperitoneal insulin on insulin sensitivity, glycaemic control and serum lipids in type 1 diabetes. Methods. Eleven patients with type 1 diabetes mellitus and chronic renal failure participated the studies. Glycated haemoglobin (HbA1c), euglycaemic hyperinsulinaemic clamp, serum lipids, and patient well-being were measured. During CAPD all patients were first treated with subcutaneous insulin and then with intraperitoneal insulin. The metabolic studies were repeated after both treatment periods for at least 3 months. Metabolic studies were performed on six of the patients also before initiation of CAPD. Results. HbA1c rose after the initiation of CAPD (from 8.85±0.54% to 9.58±0.66%, NS) and improved after changing from subcutaneous to intraperitoneally administered insulin (from 9.49±0.43% to 8.13±0.39%, P<0.01). Insulin dose increased by 15% after initiation of CAPD and 128% after switching for subcutaneous to intraperitoneal insulin. Glucose disposal rate enhanced by 39% (P=0.05) and 14% respectively (P <0.01). Initiation of CAPD had no significant effects on serum lipids but intraperitoneally administered insulin reduced HDL cholesterol and increased LDL/HDL ratio significantly. Conclusions. Intraperitoneal insulin therapy offers better glycaemic control and insulin sensitivity than subcutaneous insulin. Deterioration of HbA1c after initiation of CAPD while patients remained on subcutaneous insulin may be partly due to absorbed energy from the dialysate. Intraperitoneal insulin therapy seems to have detrimental effects on serum lipids. The clinical significance in modifying the risk of atherosclerosis remains unclear.     

Influence of variation at the apolipoprotein E locus on lipid and lipoprotein levels in CAPD patients

Background. Variation at the apolipoprotein E (apo E) locus influence lipid and lipoprotein levels in the normal population, and is associated with premature coronary artery disease. Patients with end-stage kidney disease or undergoing dialysis treatment are particularly prone to develop accelerated atherosclerosis. Methods. To evaluate the influence of genetic variation at the apo E locus, apo E genotypes and serum lipid and lipoprotein levels were measured in 51 subjects undergoing continuous ambulatory peritoneal dialysis (CAPD). Results. The distribution of apo E phenotypes and apo E allelic frequency among the CAPD subjects (&egr;2 0.049; &egr;3 0.745; &egr;4 0.206) corresponded to the healthy Swedish population. In the CAPD subjects, total serum and LDL cholesterol levels were high (6.7±1.5 mmol/l and 4.2±1.3 mmol/l respectively) and HDL cholesterol levels were low (1.2±0.5 mmol/l). When directly comparing the two major apo E groups, E 3/3 subjects (n=30) and E4/3 and 4/4 subjects, &egr;4-carriers, (n=16), LDL cholesterol levels were significantly higher among &egr;4-carriers (4,8±1.1 vs 4.0±1.2 mmol/l, P<0.03), but total serum cholesterol levels was not higher among the &egr;4-carriers (7.3±1.3 vs 6.5±1.5 mmol/l, P<0.08). Serum triglycerides or HDL cholesterol levels did not differ significantly between &agr;3-homozygotes and &egr;4-carriers. Conclusions. The results demonstrate a strong effect of variation of the apo E locus on LDL cholesterol levels in CAPD subjects, suggesting that &egr;4-carriers may be more susceptible to accelerated development of atherosclerosis in this condition.     

Extracellular fluid volume determined by bioelectric impedance and serum albumin in CAPD patients

Aim. To investigate the relationship between serum albumin and extracellular fluid volume, as measured by multifrequency bioelectrical impedance, in stable patients treated by CAPD.Method. Fifty-nine stable CAPD patients were assessed. Serum albumin (bromocresol green) and CRP, age, dialysate to plasma (D/P) creatinine ratio, normalized protein catabolic rate (nPCR), daily urine and peritoneal protein losses, and extracellular fluid volume (Vecf) were measured in each patient. Vecf was calculated as a percentage of actual body weight (Vecf% ABW), of lean body mass derived from anthropometry (Vecf% LBM) and of total body water (Vecf% Vtbw). Comparisons between those with a normal serum albumin (⩾37 g/l) and those with a low serum albumin (<37 g/l) were made by Mann-Whitney U test. Correlations with serum albumin were sought by Pearson's test. Results. The D/P creatinine ratio, daily peritoneal and urine protein losses, and extracellular fluid volume (Vecf% LBM and Vecf% Btbw) were all significantly greater in patients with serum albumin (lt;37 g/l as compared to those ⩾37 g/l; P<0.05. Age, CRP, and nPCR were not different. Serum albumin was negatively correlated with Vecf% LBM, r=-0.25; P=0.05, Vecf% Vtbs, r=-0.39; P=0.002, and daily urinary albumin loss, r=-0.25, P=0.06. Conclusion. Hypoalbuminaemia is partly dependent on subclinical overhydrationin CAPD patients. Serum albumin is negatively correlated with increased extracellular fluid volume and the proportion of Vecf to Vtbw is increased in hypoalbuminaemic patients. Multifrequency bioelectrical impedance is able to identify these abnormalities.     

Comparison of the Non-Invasive Methods Estimating Dry Weight in Hemodialysis Patients

Background. The treatment of deranged water homeostasis of hemodialysis (HD) patients needs focusing on an accurate assessment of dry weight (DW). However, the correct estimation of postdialysis DW is still a problem. Echocardiography of inferior caval vein diameter (ICVD) was recently considered as a reliable technique to estimate DWs of HD patients, whereas conductivity measurements and biochemical parameters remain controversial. In this study, we aimed to compare the noninvasive methods estimating DW in HD patients. Methods. We enrolled 60 patients: 30 hypervolemic (HV) (12 M, 18 F, with a mean age of 41.9 ± 13.6 years, mean HD duration of 38 ± 45 months) and 30 normovolemic (NV) patients (19 M, 11 F, with a mean age of 42.2 ± 14 years, mean HD duration of 62 ± 51.5 months) according to clinical sign and symptoms as well as the findings on chest x-ray. Furthermore, the DWs of patients were evaluated in post-HD period in terms of echocardiography parameters [ICVD and collapse index (CI) determined by Cheriex], plasma ANP (pANP) levels (RIA), and total body water (TBW) by bioelectrical impedance (BEI). Results. Forty-one of 60 patients had hypervolemic findings (68%) and 19 patients had normovolemia (32%) according to echocardiography parameters. Determination of “hypervolemia” by clinical acumen and pANP levels were not reliable, especially negative predictive values were lower as follows: sensitivity, specificity, positive predictive value, negative predictive values of clinical acumen and pANP levels: 63%, 69%, 87%, 50%, and 67%, 59%, 79%, 43%, respectively. TBW established by BEI did not correlate with ICVD and CI after HD (p > 0.05). The TBW of HV group according to echocardiography parameters was greater than NV group, but the difference was not statistically significant (27.4 ± 6.6 kg versus 26.4 ± 5.8 kg, respectively, p > 0.05). However, there was not any difference in the divided BSA values (1.58 ± 0.2 kg/m² versus 1.60 ± 0.2 kg/m², respectively, p > 0.05). Hypertension was seen in 37 (90%) of the echocardiographically hypervolemic patients, and the blood pressure was kept under control by previously given medication in only 7 (19%) patients. After the dry weight of the patients was corrected echocardiographically to normal limits, the blood pressure of 31 patients (86%) was normalized without antihypertensive treatment, but only in 6 patients remained the necessity of antihypertensive treatment. In addition, in 8 of 11 normotensive patients using antihypertensive drugs, assessment of their clinical and radiological findings showed normovolemia but ICVD > 11.5 mm/m²; however, the need for antihypertensive drugs disappeared when the ICVD reduced to 8–11.5/m². Conclusions. Clinical and radiological assessment, pANP levels, and TBW established by BEI appeared to be less valuable in interpreting DW's of HD patients. In accordance with the literature, echocardiography findings have proven to be reliable, and they are important noninvasive tools that can establish an effective and rational antihypertensive treatment.