Usefulness of waist circumference as a marker of abdominal adiposity in peritoneal dialysis: a cross-sectional and prospective analysis.

BACKGROUND: Waist circumference (WC) has been well recognized as a surrogate marker of abdominal adiposity. In peritoneal dialysis (PD) patients, however, aspects related to this dialysis modality, such as abdominal distension, presence of catheter and frequent hernia, raise questions regarding the reliability of WC measurements. Herein, we investigated for the first time whether WC is a reliable marker of abdominal adiposity in PD population. METHODS: This study included 107 prevalent PD patients [56% male, age 52 ± 17 years, 35% diabetics, body mass index (BMI) 24.8 ± 3.9 kg/m(2)]. WC measured at umbilicus level was evaluated against the trunk fat assessed by dual-energy x-ray absorptiometry at baseline and after 6 months. All measurements were taken with the empty abdominal cavity. RESULTS: At baseline, a strong correlation of WC with trunk fat (r = 0.81; P < 0.001) was observed. Adjusting for gender, age, dialysis vintage and BMI, WC was independently associated with trunk fat (ß = 0.30; P < 0.001; R(2) = 0.77). The agreement between WC and trunk fat was 0.59 (kappa statistic) and the area under the curve was 0.90. In the prospective evaluation, we observed that changes in WC correlated with changes in trunk fat as well (r = 0.49; P < 0.001). The kappa statistic of 0.48 remained indicative of a moderate agreement between the methods. The receiver operating characteristic curve analysis showed that WC was sensitive to detect changes in trunk fat (area under the curve 0.76). In the logistic regression analysis adjusting for gender, age and BMI, changes in WC were independently associated with changes in trunk fat. CONCLUSION: The simple anthropometric method of WC is a reliable marker of abdominal adiposity in PD patients.

Risk factors for hypovitaminosis D in nondialyzed chronic kidney disease patients.

BACKGROUND: Hypovitaminosis D is highly prevalent among patients with chronic kidney disease and has been associated with worse outcome even in the earlier stages of the disease. OBJECTIVE: This study aimed to investigate the risk factors for hypovitaminosis D in nondialyzed patients with chronic kidney disease. DESIGN: This cross-sectional study included 120 patients with chronic kidney disease at stages 2 to 5 (62% male, age: 55.4 ± 11.3 year, estimated glomerular filtration rate: 35.1 ± 15 mL/minute, body mass index [BMI]: 27.1 ± 5.2 kg/m(2), 31% diabetics). Serum 25-hydroxivitamin D [25(OH)D] was measured by chemiluminescence. Subjective global assessment, total body fat (dual-energy X-ray absorptiometry), visceral and subcutaneous abdominal fat (computed tomography), and several laboratory parameters were assessed. RESULTS: Insufficiency of 25(OH)D (15 to 30 ng/mL) was observed in 55% and deficiency (<15 ng/mL) in 20% of the patients. Patients with diabetes, BMI ≥30 kg/m(2), and who had the blood collection during the winter or spring had lower levels of 25(OH)D. Serum 25(OH)D correlated inversely with parathyroid hormone, proteinuria, insulin resistance, leptin, and subcutaneous abdominal fat. The risk factors for hypovitaminosis D were diabetes (odds ratio: 3.8; 95% CI: 1.2 to 11.7; P = .022) and BMI ≥30 kg/m(2) (odds ratio: 4.3; 95% CI: 1.2 to 15.3; P = .018). In the logistic regression analysis adjusting for gender, skin color, and season of the year, diabetes and BMI ≥30 kg/m(2) were independently associated with hypovitaminosis D. CONCLUSIONS: Diabetes and obesity were the risk factors for hypovitaminosis D in nondialyzed patients with chronic kidney disease. Effective interventional protocols of vitamin D supplementation taking into account these risk factors are warranted for this population.

Activity-related energy expenditure of patients undergoing hemodialysis.

OBJECTIVES: The aim of this study was to evaluate the activity-related energy expenditure (AEE) of patients undergoing hemodialysis (HD) and to compare it with that of healthy controls. DESIGN: This was a cross-sectional study. SETTING: This was an in-center study conducted at the Dialysis Unit, Nephrology Division, Federal University of São Paulo-Oswaldo Ramos Foundation, Brazil. PATIENTS AND METHODS: AEE was evaluated in 32 patients undergoing HD (20 men, aged: 46.3 ± 12.2 years). A subgroup consisting of 22 patients was pair-matched by gender and age with 22 sedentary, healthy individuals. AEE was measured over a period of 5 days using a portable physical activity monitor. Body fat and lean body mass were assessed by dual energy X-ray absorptiometry and body cell mass by bioelectrical impedance analysis. RESULTS: AEE correlated positively with lean body mass and body cell mass, and negatively with age, body fat, and body mass index. From the multiple regression analysis, it was found that age and lean body mass (r(2) = 0.32) or body cell mass (r(2) = 0.30) were the best among the variables that explained variations in AEE. AEE of HD patients in comparison with healthy controls was found to be lower on dialysis days (234 [9.5 to 1,145] kcal/day vs. 565 [214 to 1,319] kcal/day, median [range]; P < .01) as well as on nondialysis days (369 [89.5 to 1,242] kcal/day vs. 565 [214 to 1,319] kcal/day; P = .02). Total energy expenditure of the HD patients on dialysis days (2,051 ± 289 kcal/day) as well as nondialysis days (2,202 ± 283 kcal/day) was also found to be lower in comparison with controls (2,514 ± 307 kcal/day; P < .01). The average contribution of the AEE toward total energy expenditure in HD patients was 15%, whereas in controls it was 24% (P = .03). CONCLUSION: As compared with sedentary, healthy individuals, AEE was reported to be considerably lower in HD patients.

Underreporting of energy intake in peritoneal dialysis patients.

OBJECTIVES: This study aimed to assess the prevalence of underreporting among patients treated by peritoneal dialysis (PD), and to investigate whether the reported energy intake is influenced by overweight status in this population. DESIGN: This was a prospective, observational study. SETTING: This study took place at the Dialysis Unit of the Nephrology Division, Federal University of São Paulo-Oswaldo Ramos Foundation, São Paulo, Brazil. PATIENTS: Forty adult patients were recruited: 24 men and 16 women; age, 53.4+/-16.5 years; body mass index (BMI), 25.1+/-3.8 kg/m(2) (x+/-SD); median duration of dialysis, 19 months (range, 3 to 101 months). Only patients on PD >3 months, free of peritonitis for at least 3 months, without catabolic conditions and with normal thyroid function, were included. METHODS: Energy intake was evaluated using a 3-day food record. Resting energy expenditure (REE) was measured by indirect calorimetry. Body composition was assessed using dual-energy x-ray absorptiometry. The total energy (TE) offered was considered the sum of energy intake plus energy provided by glucose absorption. All measurements were collected at baseline and after 6 months. Underreporting of energy intake was considered to have occurred when the TE/REE ratio was <1.40. RESULTS: The TE/REE ratio was 1.35+/-0.31. Twenty-one patients (52.5%) had a TE/REE ratio <1.40. The TE/REE ratio correlated negatively with BMI (r=-0.52, P < .01), and positively with duration of dialysis (r=0.44, P < .01). No correlation was found between TE/REE ratio and any other variables. Patients were divided into two groups according to BMI <25 kg/m(2) and BMI > or =25 kg/m(2). The majority of patients (83.3%) in the higher BMI group had a TE/REE ratio <1.40. In a logistic regression analysis, using TE/REE ratio <1.40 or > or =1.40 as the dependent variable, BMI> or =25 kg/m2 was the only determinant of energy underreporting. After 6 months of follow-up, no change in either body weight or BMI was evident. CONCLUSIONS: This study showed that a significant number of PD patients underreported the energy intake evaluated by 3-day food diaries. This finding was evidenced particularly in overweight patients.

[Hemoglobin levels in hemodialysis patients treated with epoetin: a Brazilian experience]. / Variação dos níveis de hemoglobina de pacientes em hemodiálise tratados com eritropoetina: uma experiência brasileira.

OBJECTIVE: Correction of anemia using epoetin decreases morbidity and increases survival and quality of life in end-stage renal disease. Maintaining hemoglobin levels within the range proposed by guidelines has become a major challenge, with hemoglobin cycling affecting more than 90% of patients undergoing hemodialysis. The variability of hemoglobin levels over time was assessed in our patients. METHODS: Data were retrospectively collected on 249 patients undergoing hemodialysis over a 3-year period at seven centers in Brazil. Hemoglobin was measured at least monthly, and target levels were those between 10.5 g/dL and 12.5 g/dL. Patients were grouped into six categories of variability consistently low (<10.5 g/dL), consistently target range (10.5 to 12.5 g/dL), consistently high (>12.5 g/dL), low amplitude fluctuation with low hemoglobin levels, low amplitude fluctuation with high hemoglobin levels and high amplitude fluctuation. None of the patients maintained stable hemoglobin levels for the entire 36-month period. RESULTS: The mean monthly proportion of patients that had hemoglobin levels within the target range was 50% (range, 42% to 61%). Mean levels above the target (30%) were more frequent than those below it (20%). During 6, 12, and 36 months, proportions of patients with consistently low levels of hemoglobin decreased from 3.6% to 0%, from 31.7% to 2.8% for those with consistently high, from 7.6% to 0% for those with low amplitude fluctuation with low hemoglobin levels and from 41.3% to 8.3% for those with low amplitude fluctuation with high hemoglobin levels. However, the proportions of patients with high amplitude fluctuation increased from 21.5% to 88.9%. CONCLUSION: Maintaining hemoglobin levels within the target range is difficult, especially for longer periods of time. Missing the target seems more often due to levels above it, but high-amplitude fluctuations eventually occur in the majority of patients.

Clinical outcomes of incident peritoneal dialysis patients coming from kidney transplantation program: A case-control study.

INTRODUCTION: Brazil ranks second in the absolute number of transplantations in the world. Despite improvements in graft survival, many patients will progress to graft loss and return to dialysis. Concerns exist regarding adverse clinical outcomes in this population when undergone peritoneal dialysis (PD). OBJECTIVE: To compare the occurrence of mortality, technique failure, and peritonitis among incident patients in PD coming from either Tx or pre-dialysis treatment. METHODOLOGY: A retrospective study in which 47 adult patients with Tx failure (Tx group) were matched for age, gender, diabetes mellitus (DM), modality and start year of PD, with 1:1 predialysis patient (nTx group). The Fine-Gray competing risk model was used to analyze mortality and technique failure. RESULTS: Compared to nTx, the Tx group had a lower body mass index, serum potassium, and albumin concentrations. A higher ferritin level, transferrin saturation and the number of patients with positive serology for viral hepatitis were also observed in the Tx group. In the multivariate analysis, patients of the Tx group had 4.4-times higher risk of death (p = 0.007), with infection as the main cause. Technique failure and peritonitis were similar in both groups. CONCLUSION: Previous Tx is a risk factor for mortality but not for technique failure or peritonitis in incident patients on a PD program.

Associated factors related to chronic kidney disease progression in elderly patients.

BACKGROUND: Chronic Kidney Disease (CKD) is a worldwide public health problem. The prevalence of CKD is rising especially in elderly, as consequence of population-ageing related to socioeconomic development and better life expectancy. There are scarce studies evaluating CKD progression and its associated factors in elderly patients. METHODS: This is a retrospective observational study including 340 patients (≥ 65 years old) CKD stages 3a-5 non-dialysis, incidents in an outpatient CKD clinic, followed by 2.1 years. CKD progression was assessed by the slope of eGFR calculated by CKD-EPI and BIS 1 equations. The patients were divided in progressor and non-progressor groups (eGFR slope < or ≥ 0 mL/min/1.73 m2/year, respectively). RESULTS: Kidney function declined in 193 (57%) patients. In this group, the progression rate was -2.83 (-5.1 / -1.1) mL /min /1.73 m2 /year. Compared to non progressor, the progressor patients were younger [72 (69-78) vs. 76 (69-80) years; p = 0.02]; had higher proportion of diabetic nephropathy, higher serum phosphorus [3.8 (3.3-4.1) vs. 3.5 (3.9-4.1) mg/dL; p = 0.04] and proteinuria [0.10 (0-0.9 vs. 0 (0-0.3)] g/L; p = 0.007)] at the admission. In the logistic regression analysis adjusted for gender and eGFR, proteinuria was independently associated with CKD progression [OR (Odds Ratio) (1.83; 95% CI, 1.17-2.86; p < 0.01)]. CONCLUSION: CKD progression was observed in the majority of elderly CKD patients and proteinuria was the most important factor associated to the decline of kidney function in this population.

Association of changes in bone remodeling and coronary calcification in hemodialysis patients: a prospective study.

BACKGROUND: Vascular calcification is common and constitutes a prognostic marker of mortality in the hemodialysis population. Derangements of mineral metabolism may influence its development. The aim of this study is to prospectively evaluate the association between bone remodeling disorders and progression of coronary artery calcification (CAC) in hemodialysis patients. STUDY DESIGN: Cohort study nested within a randomized controlled trial. SETTING & PARTICIPANTS: 64 stable hemodialysis patients. PREDICTOR: Bone-related laboratory parameters and bone histomorphometric characteristics at baseline and after 1 year of follow-up. OUTCOMES: Progression of CAC assessed by means of coronary multislice tomography at baseline and after 1 year of follow-up. Baseline calcification score of 30 Agatston units or greater was defined as calcification. Change in calcification score of 15% or greater was defined as progression. RESULTS: Of 64 patients, 38 (60%) of the patients had CAC and 26 (40%) did not [corrected]. Participants without CAC at baseline were younger (P < 0.001), mainly men (P = 0.03) and nonwhite (P = 0.003), and had lower serum osteoprotegerin levels (P = 0.003) and higher trabecular bone volume (P = 0.001). Age (P = 0.003; beta coefficient = 1.107; 95% confidence interval [CI], 1.036 to 1.183) and trabecular bone volume (P = 0.006; beta coefficient = 0.828; 95% CI, 0.723 to 0.948) were predictors for CAC development. Of 38 participants who had calcification at baseline, 26 (68%) had CAC progression in 1 year. Progressors had lower bone-specific alkaline phosphatase (P = 0.03) and deoxypyridinoline levels (P = 0.02) on follow-up, and low turnover was mainly diagnosed at the 12-month bone biopsy (P = 0.04). Low-turnover bone status at the 12-month bone biopsy was the only independent predictor for CAC progression (P = 0.04; beta coefficient = 4.5; 95% CI, 1.04 to 19.39). According to bone histological examination, nonprogressors with initially high turnover (n = 5) subsequently had decreased bone formation rate (P = 0.03), and those initially with low turnover (n = 7) subsequently had increased bone formation rate (P = 0.003) and osteoid volume (P = 0.001). LIMITATIONS: Relatively small population, absence of patients with severe hyperparathyroidism, short observational period. CONCLUSIONS: Lower trabecular bone volume was associated with CAC development, whereas improvement in bone turnover was associated with lower CAC progression in patients with high- and low-turnover bone disorders. Because CAC is implicated in cardiovascular mortality, bone derangements may constitute a modifiable mortality risk factor in hemodialysis patients.

Phosphate binder impact on bone remodeling and coronary calcification--results from the BRiC study.

BACKGROUND AND AIMS: Calcium-containing phosphate binders have been shown to increase the progression of vascular calcification in hemodialysis patients. This is a prospective study that compares the effects of calcium acetate and sevelamer on coronary calcification (CAC) and bone histology. METHODS: 101 hemodialysis patients were randomized for each phosphate binder and submitted to multislice coronary tomographies and bone biopsies at entry and 12 months. RESULTS: The 71 patients who concluded the study had similar baseline characteristics. On follow-up, the sevelamer group had higher levels of intact parathyroid hormone (498 +/- 352 vs. 326 +/- 236 pg/ml, p = 0.017), bone alkaline phosphatase (38 +/- 24 vs. 28 +/- 15 U/l, p = 0.03) and deoxypyridinoline (135 +/- 107 vs. 89 +/- 71 nmol/l, p = 0.03) and lower LDL cholesterol (74 +/- 21 vs. 91 +/- 28 mg/dl, p = 0.015). Phosphorus (5.8 +/- 1.0 vs. 6 +/- 1.0 mg/dl, p = 0.47) and calcium (1.27 +/- 0.07 vs. 1.23 +/- 0.08 mmol/l, p = 0.68) levels did not differ between groups. CAC progression (35 vs. 24%, p = 0.94) and bone histological diagnosis at baseline and 12 months were similar in both groups. Patients of the sevelamer group with a high turnover at baseline had an increase in bone resorption (eroded surface, ES/BS = 9.0 +/- 5.9 vs. 13.1 +/- 9.5%, p = 0.05), whereas patients of both groups with low turnover at baseline had an improvement in bone formation rate (BFR/BS = 0.015 +/- 0.016 vs. 0.062 +/- 0.078, p = 0.003 for calcium and 0.017 +/- 0.016 vs. 0.071 +/- 0.084 microm(3)/microm(2)/day, p = 0.010 for sevelamer). CONCLUSIONS: There was no difference in CAC progression or changes in bone remodeling between the calcium and the sevelamer groups.

Is UCP2 gene polymorphism associated with decreased resting energy expenditure in nondialyzed chronic kidney disease patients?

OBJECTIVE: The deletion/deletion (del/del) polymorphism of uncoupling protein 2 (UCP2) was associated with decreased energy expenditure in diabetic and obese patients. There is evidence of decreased resting energy expenditure (REE) in chronic kidney disease (CKD) patients not yet on dialysis. However, whether REE is associated with the UCP2 polymorphism was not previously investigated in this population. This study evaluated whether the del/del polymorphism of the UCP2 gene is associated with lower REE in nondialyzed CKD patients. DESIGN: This was a cross-sectional study. PATIENTS AND METHODS: Forty-four nondialyzed CKD patients (29 male; aged 52 +/- 12 years; creatinine clearance, 37 +/- 13 mL/min/1.73 m(2) [values are mean +/- SD unless otherwise noted]) were included. Their REE was assessed by indirect calorimetry, and body composition by bioelectrical impedance. High-sensitivity C-reactive protein (hs-CRP) was also evaluated. The insertion/deletion (ins/del) polymorphism of the UCP2 gene was determined in all participants. To test whether the deletion/deletion (del/del) polymorphism of the UCP2 gene was associated with lower REE, the REE of carriers of the del/del genotype (n = 24; group Del) was compared with that of carriers of the insertion and ins/del genotype (n = 20; group Ins). MAIN OUTCOME MEASURE: The main outcome measure was REE. RESULTS: The REE of group Del was similar to that of the group Ins (1379 +/- 239 kcal/day vs. 1360 +/- 289 kcal/day, respectively, P = NS). This result was maintained even after the REE was adjusted for lean body mass by analysis of covariance. In addition, in a multiple-regression analysis using REE as the dependent variable, only lean body mass and hs-CRP were significant predictors of REE. CONCLUSION: The results suggest that the del/del polymorphism of the UCP2 gene is not associated with lower REE in nondialyzed CKD patients.

Factors associated with body-fat changes in prevalent peritoneal dialysis patients.

BACKGROUND: Changes in body fat (BF) were shown to occur over time in peritoneal dialysis (PD) patients. However, the factors associated with BF changes have not been fully investigated in this population. METHODS: We studied 45 patients (25 were male; age, 53, SD +/- 15 years; 21 continuous ambulatory peritoneal dialysis/24 automated peritoneal dialysis; PD vintage, 14 ([range, 3 to 104] months; 40% were diabetic; 31% were previously treated by hemodialysis). Body composition was assessed by dual-energy X-ray absorptiometry and bioelectric impedance analysis, nutritional status was assessed by subjective global assessment, energy intake was assessed by 3-day food records, and resting energy expenditure (REE) was assessed by indirect calorimetry. Glucose absorption, serum bicarbonate, and C-reactive protein were also evaluated. All measurements were performed at baseline and after 12 months. RESULTS: Large variability in BF changes was observed among patients: 53% gained BF (+3.0 +/- 2.8), whereas 47% lost BF (-2.3, SD +/- 1.4). At baseline, groups were similar regarding sex, age, percent diabetics, DP modality, characteristics of peritoneal transport, residual renal function, energy intake, glucose absorption, and REE. However, patients who gained BF had lower BF (16.3, SD +/- 6.9 kg, versus 20.9, SD +/- 6.5 kg; P = .03), had a higher ratio of total energy offered (intake plus absorbed glucose) to REE (1.45, SD +/- 0.39, versus 1.26, SD +/- 0.24; P = .04), and were on PD for a shorter time (10 [range, 3 to 104] versus 20 [range, 4 to 76] months; P = .03). This group also had a higher proportion of malnourished patients (50% versus 19%; P = .03) and of patients previously treated by hemodialysis (46% versus 14%; P = .03). After 12 months, a reduction in the frequency of malnutrition (50% to 25%; P = .02) was observed in the group of patients with increased BF. Patients who lost BF reduced their body cell mass (from 21.7 [SD +/- 5.1 kg] to 20.7 [SD +/- 5.0 kg]; P < .01) and level of serum bicarbonate (from 22.7 [SD +/- 3.7 mmol/L] to 20.9 [SD +/- 3.1 mmol/L]; P < .01). Moreover, this group had an increase in frequency of malnutrition (from 19% to 38%; P = .02), a reduction in the proportion of patients with residual renal function (from 62% to 43%; P = .03), and a higher number of hospitalizations (from 25% to 4%; P = .02) during follow-up. Glucose absorption and C-reactive protein were not associated with BF changes. A regression analysis showed that baseline body mass index was independently associated with a gain of BF (-0.19, SE = 0.09, P = .04), and that hospitalization during follow-up was associated with a loss of BF (2.35, SE = 1.19, P = .04). CONCLUSIONS: Prevalent PD patients exhibited a large variability in BF changes. Baseline body mass index and hospitalizations during follow-up were the most important factors associated with these changes.

Divergences in antihypertensive therapy in special situations in nephrology.

CONTEXT AND OBJECTIVE: The choice of an antihypertensive drug is based on several criteria and specific situations give rise to doubt and controversy. The aim here was to evaluate physicians approaches towards treatment with antihypertensive agents in specific situations. DESIGN AND SETTING: Cross-sectional study, at Universidade Federal de São Paulo, São Paulo. METHODS: A questionnaire was applied during a nephrology meeting to evaluate individual approaches towards each hypothetical clinical situation. The questionnaire consisted of five multiple-choice questions (clinical cases) concerning controversial aspects of antihypertensive therapy. RESULTS: A total of 165 questionnaires were analyzed. Most participants were nephrologists (93.2%). There was a preference for angiotensin-converting enzyme (ACE) inhibitors in at least two of the cases. Only 57.2% of the physicians were correct in choosing beta-blockers as the first-line drugs for patients with ischemic coronary disease. Moreover, 66.2% chose ACE inhibitors as the first-line drugs for patients with chronic kidney disease and proteinuria. About 5% of the physicians did not follow the current recommendations for the use of ACE inhibitors in diabetic patients with microalbuminuria. The most controversial question concerned the first-line drug for advanced chronic kidney disease. Most physicians were correct in choosing calcium channel blockers and avoiding ACE inhibitors in renovascular hypertension in the case of a patient with a single functioning kidney. CONCLUSIONS: Most physicians adopted the correct approach, but some had an alternative strategy for the same situations that was not based on evidence.

The progression and impact of vascular calcification in peritoneal dialysis patients.

BACKGROUND: Progression of coronary artery calcification (CAC) has been described in hemodialysis patients, and severe CAC has been associated with the occurrence of cardiovascular events in this population. Little information is available regarding peritoneal patients. AIM: To prospectively evaluate peritoneal dialysis patients in order to identify the variables associated with the rate of CAC progression, as well as to determine the impact that baseline CAC has on clinical outcomes over a 1-year follow-up period. METHODS: Using multislice coronary tomography, calcium scores were estimated at baseline and after 12 months in 49 peritoneal dialysis patients. Patients with and without CAC progression were compared with respect to clinical characteristics and biochemical variables, including lipid profile, parameters of mineral metabolism, and markers of inflammation. Cardiovascular events, hospitalizations, and all-cause mortality were recorded. RESULTS: At baseline, 29 patients (59%) presented CAC and a median calcium score of 234.7 (range 10.3-2351) Agatston units. Progression of CAC was observed in 13 patients (43%) who, in comparison with those presenting no CAC progression, were older, presented higher baseline calcium scores, and had higher mean glucose levels, lower mean high density lipoprotein cholesterol levels, and more months using low calcium peritoneal solution. We also observed a trend toward more often presenting with a history of hypertension, exhibiting more hyperphosphatemic and hyperglycemic events, and having lower albumin levels. In multiple logistic regression, only baseline calcium score was independently associated with progression of CAC. A shorter cardiovascular event-free time and a trend toward lower survival rates were observed in the group with CAC. Hospitalization event-free time did not differ between the groups. CONCLUSION: Determining CAC provides important prognostic data in peritoneal dialysis patients. Baseline calcium score and disturbances in glucose, mineral, and lipid metabolism were indicative of higher risk of CAC progression in this population.

Homocysteine and its determinants in nondialyzed chronic kidney disease patients.

This cross-sectional study aimed to investigate the prevalence of hyperhomocysteinemia, the determinants of plasma total homocysteine concentrations, and the relationship of total homocysteine with nutritional parameters in a sample of patients with chronic kidney disease (CKD) and not yet on dialysis. The study was done with outpatients from the Nephrology Division of the Federal University of São Paulo and Oswaldo Ramos Foundation. Sixty-six patients with CKD (70% male; age 58.6+/-15.6 years [mean+/-standard deviation]) with moderate to severe renal impairment (creatinine clearance=29.8+/-14.3 mL/min [0.5+/-0.24 mL/sec]), clinically stable, and older than 18 years were included. A group of 20 healthy subjects from the clinic staff was also studied for reference values for plasma homocysteine, folate, and vitamin B-12 concentration. Fasting blood samples were collected to determine plasma total homocysteine, folate, vitamin B-12, and creatinine. To calculate creatinine clearance, a 24-hour urine collection sample was obtained. The assessment of nutritional status included anthropometric parameters. Pearson correlation, Mann-Whitney test, and multiple linear regression analysis were used for statistical analyses. The main results showed that the concentration of total homocysteine in the patients was significantly increased compared with the healthy subjects (3.4+/-1.7 vs 1.41+/-0.42 mg/L [25.4+/-12.2 vs 10.4+/-3.1 micromol/L]; P<0.001). Plasma folate and plasma vitamin B-12 were in the normal range and did not differ between patients and healthy individuals. A high prevalence of hyperhomocysteinemia (total homocysteine >1.89 mg/L [14 micromol/L]) was found in the patients (89%). Plasma total homocysteine did not correlate with any of the nutritional parameters studied and did not differ between patients in terms of whether they were using or not using folic acid supplementation (3.07+/-1.09 vs 3.55+/-1.78 mg/L [22.7+/-8.1 vs 26.3+/-13.2 micromol/L]; P=0.47), although plasma folate was significantly higher in the supplemented group (12.6+/-3.0 vs 8.0+/-3.6 ng/mL [28.5+/-6.8 nmol/L vs 18.1+/-8.2 nmol/L]; P<0.001). According to the multiple regression analysis, the determinants of total homocysteine were only plasma folate, plasma vitamin B-12, and creatinine clearance (r2=0.20). In conclusion, a high prevalence of hyperhomocysteinemia was found in our sample of nondialyzed patients with CKD. The determinants of total homocysteine levels were plasma folate, plasma vitamin B-12, and creatinine clearance. No association between nutritional parameters and total homocysteine was observed.

Coronary artery calcification, systemic inflammation markers and mineral metabolism in a peritoneal dialysis population.

AIMS: To assess the prevalence of coronary artery calcification (CAC) in peritoneal dialysis (PD) patients and to determine whether comorbidities such as inflammation, dyslipidemia and mineral metabolism disorders correlate with its development. METHODS: Forty-nine PD patients (45% male; median age, 52 years) were submitted to multislice computed tomography. Inflammatory markers, anti-oxidized LDL antibody, calcium-phosphate balance and lipid profiles were assessed. RESULTS: Twenty-nine patients (59.2%) presented CAC (median calcium score, 234.7 Agatston units). Patients with CAC were older than those without, more frequently presented a history of coronary artery disease or hypertension and had lower HDL cholesterol levels, as well as presenting higher levels of osteoprotegerin and LDL oxidation. The logistic regression revealed that the independent determinants of CAC were age (odds ratio = 1.12; p = 0.006) and number of prescribed anti-hypertensive drugs (odds ratio = 2.38; p = 0.048). When the population was stratified by calcium score quartile, soluble Fas levels were significantly higher in patients with severe calcification. In patients younger than 45, CAC correlated positively with phosphorus levels (r = 0.52; p = 0.04). CONCLUSION: In PD patients, CAC is highly prevalent. Our results indicate that conditions such as inflammation and mineral disturbances are associated with its development.

Nutritional parameters and mortality in incident hemodialysis patients.

OBJECTIVE: To evaluate the impact of nutritional parameters at the time of initiation of hemodialysis (HD) on mortality. DESIGN: Retrospective study. SETTING: Dialysis Unit of the Federal University of Sao Paulo, Oswaldo Ramos Foundation. PATIENTS: Three hundred forty-four incident HD patients (60.5% male, 26% diabetic) with the first nutritional evaluation performed before completing 3 months of onset of HD were included. METHODS: The study consisted of baseline measurements of several nutritional parameters (triceps skinfold thickness [TSF], midarm muscle circumference [MAMC], body mass index [BMI], serum albumin, serum creatinine, and protein and energy intake assessed by 3-day food diary) and records of outcome (death) over a period of 10 years. RESULTS: Muscle and/or fat depletion was observed in 51% of the studied patients, according to the percent standard of MAMC and TSF, respectively. Presence of diabetes, age over 60 years, serum albumin < 3.5 g/dL, MAMC adequacy < 90%, protein intake < 1.0 g/kg/d, and energy intake < 25 kcal/kg/d were associated with worse survival. When patients were analyzed according to tertiles of dialysis vintage, BMI > or = 25 (calculated as kg/m2) had a negative impact on survival only in the highest tertile (> 2.45 years). Patients with BMI < 25 and MAMC adequacy > or = 90% showed the best survival over the study period, and those with BMI > or = 25 but MAMC adequacy < 90% had the worst survival (P = .004). In the multivariate survival analysis adjusting for diabetes, advanced age, and hypoalbuminemia, the reduced MAMC (P = .008) and the low energy intake (P = .03) were independent predictors of death in incident HD patients. CONCLUSIONS: Reduced MAMC and low energy intake at the beginning of chronic dialysis are risk factors for mortality. A negative effect of high BMI on survival was associated with reduced MAMC and longer dialysis vintage.

Is energy intake underestimated in nondialyzed chronic kidney disease patients?

OBJECTIVE: To evaluate whether energy intake of nondialyzed chronic kidney disease (CKD) patients is underestimated. DESIGN: Cross-sectional study. SETTING: Outpatient clinic of the Federal University of Sao Paulo, Oswaldo Ramos Foundation. PATIENTS: One hundred and thirty-one nondialyzed CKD patients (86 male, 66%; body mass index [BMI] 26 +/- 4.21, mean +/- standard deviation) were included. Body weight change was evaluated after 6 to 12 months in 59 patients of the entire group. METHODS: Energy intake was evaluated using 4-day food diaries (3 weekdays and 1 weekend day), and resting energy expenditure (REE) was measured by indirect calorimetry. The ratio of energy intake to REE (EI/REE) was used to evaluate the accuracy of the recorded energy intake. An EI/REE ratio below 1.27 was used to identify patients who were underreporting their current energy intake. RESULTS: The majority of the patients reported an energy intake substantially below the recommendation (22.4 +/- 7.15 kcal/kg/d) and had an EI/REE ratio lower than 1.27. In patients with a BMI >or= 25, the mean EI/REE ratio was significantly lower than that of patients with a BMI < 25 (1.01 +/- 0.28 versus 1.27 +/- 0.42, P < .01, respectively). In addition, only in the group with higher BMI was the mean ratio indicative of underreporting. When the body weight of a subgroup of patients (n = 59) was evaluated after 7.9 +/- 2.4 months, it was observed that the subgroup of patients who maintained or gained body weight had a mean EI/REE not compatible with this condition (1.13 +/- 0.38). The low ratio, despite increasing or maintaining body weight, is highly suggestive of underreported energy intake. CONCLUSION: Energy intake of nondialyzed CKD patients seemed to be underestimated and was more pronounced in overweight and obese patients.

Resting energy expenditure of chronic kidney disease patients: influence of renal function and subclinical inflammation.

BACKGROUND: The resting energy expenditure (REE) of patients with chronic kidney disease (CKD) might be influenced by the degree of renal function and by a subclinical inflammatory condition. The aim of this study is to evaluate the impact of these 2 variables on the REE of patients with CKD. METHODS: A cross-sectional study was performed on 91 nondialyzed and nondiabetic patients with CKD with no clinical signs of inflammation. Patients were divided into quartiles of creatinine clearance (CrCl) and tertiles of C-reactive protein (CRP) level. REE was measured by means of indirect calorimetry, and the presence of a subclinical inflammatory condition was assessed by means of serum CRP concentration. RESULTS: CrCl interquartile ranges calculated were: quartile 1 (CrCl < or = 18 mL/min [< or =0.30 mL/s]; n = 24); quartile 2 (CrCl, 19 to 29 mL/min [0.31 to 0.48 mL/s]; n = 22); quartile 3 (CrCl, 30 to 42 mL/min [0.49 to 0.70 mL/s]; n = 23), and quartile 4 (CrCl > or = 43 mL/min [> or =0.71 mL/s]; n = 22). Nonadjusted REE and REE adjusted for sex, age, and lean body mass did not differ among the 4 CrCl quartiles. The following ranges were calculated for CRP tertiles: tertile 1 (CRP < or = 0.14 mg/dL; n = 30), tertile 2 (CRP, 0.15 to 0.49 mg/dL; n = 31), and tertile 3 (CRP > or = 0.50 mg/dL; n = 30). The nonadjusted REE in CRP tertile 3 was significantly greater than those in tertiles 1 and 2. REE adjusted for sex, age, and lean body mass was greater in CRP tertile 3 than tertile 1, a difference equivalent to 123.7 kcal/d (P = 0.003; 95% confidence interval, 42.9 to 204.5). A borderline difference was observed between CRP tertiles 3 and 2. When analyzing the entire group, REE did not correlate with either serum creatinine level or CrCl, and a borderline correlation between REE and log of CRP was observed (r = 0.19; P = 0.07). CONCLUSION: This study suggests that REE is not influenced by degree of renal function, but it may be elevated during a condition of subclinical inflammation.

Comparison of three methods for the determination of body fat in patients on long-term hemodialysis therapy.

OBJECTIVE: To compare three simple methods of body composition analysis for the assessment of body fat in patients on long-term hemodialysis therapy. DESIGN: Cross-sectional study using the skinfold thickness, bioelectrical impedance analysis, and near-infrared interactance techniques after a hemodialysis session. SUBJECTS/SETTING: Ninety clinically stable patients (57 male/33 female) undergoing hemodialysis at the Dialysis Unit of the Federal University of São Paulo. STATISTICAL ANALYSIS: Analysis of variance, intraclass correlation coefficient, and Bland-Altman plot analysis were used for the comparative analysis between the methods. RESULTS: Body fat measurements obtained by skinfold thickness (13.5+/-6.2 kg) and bioelectrical impedance analysis (13.7+/-6.7 kg) were similar, whereas those measured by near-infrared interactance (11.3+/-5.1 kg) were significantly lower in comparison with skinfold thickness and bioelectrical impedance analysis (P<.001). The strongest intraclass correlation coefficient was found between bioelectrical impedance analysis and skinfold thickness (r=0.87), and near-infrared interactance vs skinfold thickness and bioelectrical impedance analysis methods yielded r=0.78 and r=0.76, respectively. Near-infrared interactance showed a progressive underestimation of body fat values in comparison with the bioelectrical impedance analysis technique in patients with higher amount of adiposity. CONCLUSION: In our study, we cannot consider that one method of body composition analysis is more accurate than the other because we did not apply a gold standard method. However, the most simple, long-established, and inexpensive method of skinfold thickness seems to be still very useful to the dietitians' routine for assessing body fat in patients on long-term hemodialysis therapy.

A model for improving quality in nephrology settings.

Continuous quality improvement (CQI) programs have been instituted in many health care organizations over the last decade. PDCA, a tool composed of planning (P), doing (D), checking (C), and acting (A), has proved to be very useful in the CQI problem-solving process. The use of the PDCA tool described in this article resulted in the successful resolution of a hepatitis B outbreak in a Brazilian hemodialysis population and can serve as a model methodology for improving care in nephrology settings.