Dietary Patterns, Dietary Adequacy and Nutrient Intake in Adults Commencing Peritoneal Dialysis: Outcomes from a Longitudinal Cohort Study

(1) Background: Optimal dietary intake is integral to good health in people receiving peritoneal dialysis (PD). We investigated how dietary patterns, dietary adequacy and nutrient intake may change over time in people commencing PD. (2) Methods: Participants were attending the PD training unit for the commencement of peritoneal dialysis, aged ≥18 years and willing to complete food records. Misreporters were excluded from the analysis. Dietary intake was compared at PD commencement and at 12 months. Intake was also compared to reference standards. Dietary patterns were derived using principal component analysis. (3) Results: There were no significant changes between baseline and 12 months for grains, fruit, vegetables and meat. Dairy and added sugar intake was significantly lower (p = 0.01). The intake of energy and protein was adequate and did not change. There was a significant reduction in dietary phosphorus and calcium, and increased vitamin C intake. Three dietary patterns were identified: the 'Bread and Cereal' pattern; 'Milk and Potatoes' pattern; and the 'Semi Vegetarian' pattern. (4) Conclusions: In this longitudinal cohort study, the diet quality was suboptimal and there were limited changes in intake after the commencement of PD. Further exploration of how dietary patterns may impact outcomes and quality of life is warranted.

Serotonergic regulation of appetite and sodium appetite

Serotonin is a neurotransmitter that is synthesized and released from the brainstem raphe nuclei to affect many brain functions. It is well known that the activity of raphe serotonergic neurons is changed in response to the changes in feeding status to regulate appetite via the serotonin receptors. Likewise, changes in volume status are known to alter the activity of raphe serotonergic neurons and drugs targeting serotonin receptors were shown to affect sodium appetite. Therefore, the central serotonin system appears to regulate ingestion of both food and salt, although neural mechanisms that induce appetite in response to hunger and sodium appetite in response to volume depletion are largely distinct from each other. In this review, we discuss our current knowledge regarding the regulation of ingestion - appetite and sodium appetite - by the central serotonin system.

Reduced phosphorus is associated with older age and hypoalbuminemia. Risk factors for all-cause mortality in peritoneal dialysis patients

Introduction/aim

Hyperphosphatemia is a mortality risk factor in dialysis patients; however, low phosphorus levels too. Diabetes and malnutrition are strongly associated with mortality and with reduced serum phosphorus. This study analyzed the pattern of serum phosphorus in patients on Peritoneal Dialysis (PD) and its association with mortality.

Methods

A Secondary analysis was performed on a multicenter cohort study in peritoneal dialysis patients from two previous studies done by our group.

Results

Six hundred fifty-four patients were included. Serum phosphorus was <3.6 mg/dL in 28.29% of patients, 3.6 to 5.2 mg/dL in 48.16%, and >5.2 mg/dL in 23.55%. In logistic regression analysis; education, age, and hypoalbuminemia were risk factors for low P levels. In multivariate Cox analysis P < 3.6 mg/dL, age, and low albumin were predictors for all-cause mortality. When lower P and lower albumin were combined, this group had the highest risk for all cause and cardiovascular mortality.

Conclusion

The frequency of patients with reduced serum phosphorus was higher in the Mexican population than in Europe or Asia. Low serum phosphorus levels, older age and hypoalbuminemia were risk factors for all-cause mortality. Low phosphorus combined with low albumin levels were the highest risk factor for all-cause and cardiovascular mortality.

Prevalence and determinants of low plasma zinc levels in adult peritoneal dialysis patients

OBJECTIVE

Zinc is an essential trace element, being a cofactor for almost 300 enzymes. As zinc is widely available in the diet, the European Best Practice Guidelines do not recommend routine supplementation in dialysis patients. However, some medicines prescribed to dialysis patients may potentially reduce absorption, and there may be increased losses with dialysis. As older and co-morbid patients are now treated by peritoneal dialysis (PD) we wished to determine the prevalence of patients with low plasma zinc levels.

DESIGN AND METHODS

We prospectively measured plasma zinc in 550 PD patients attending for their first peritoneal membrane assessment using atomic absorption spectroscopy. Body composition was determined by bioimpedance.

RESULTS

Plasma zinc was measured in 550 patients, mean age 58.7 years, 60.6% male, mean value 10.8 ± 2.2 umol/L, with 66.5% having low zinc levels (<11.5 umol/L). Normal plasma zinc was associated with haemoglobin (odds ratio (OR) 1.41 (95% confidence limits (95%CL) 1.22-1.63), serum albumin (OR 1.04 (95%CL 1.002-1.087), higher glucose dialysates L/day (OR 1.06 (1.001-1.129), and negatively with 24-hour urinary protein losses (OR 0.786 (95%CL 0.673-0.918) and age (OR 0.985 (95%CL 0.972-1.0). There was no association with dialysis adequacy, original renal disease or dietary protein estimation. Prescription of phosphate binders had no effect on zinc levels (10.7 ± 2.2 vs 10.8 ± 2.3 umol/L).

CONCLUSIONS

Most PD patients had low plasma zinc levels, associated with older age, probably reflecting reduced intake, urinary protein losses, and lower albumin and haemoglobin most likely linked to greater co-morbidity, low grade inflammation and volume expansion requiring higher glucose dialysates.

Frailty, appendicular lean mass, osteoporosis and osteosarcopenia in peritoneal dialysis patients

INTRODUCTION

The pattern of chronic kidney disease mineral bone disorder (CKD-MBD) is changing with increasing numbers of elderly patients now treated by dialysis. The risk of falls and bone fractures increases with frailty and sarcopenia. As such we wished to review the association between osteoporosis and frailty and loss of appendicular lean mass (ALM).

METHODS

Dual-energy X-ray absorptiometry (DXA) was used to measure lumbar spine and femoral neck bone mineral density (BMD) and body composition. Osteoporosis and osteopenia were defined according to T scores. ALM was indexed to height (ALMI). Frailty was classified using the clinical frailty scale (CFS).

RESULTS

DXA scans from 573 patients, 57.8% male, 36.8% diabetic, mean age 61.0 ± 15.8 years, with a median 6.0 (2-20) months of treatment with PD were reviewed. Forty-two (7.3%) were classified as clinically frail, 115 (20%) osteoporotic, and 198 (34.6%) ALMI meeting sarcopenic criteria, with 43% of osteoporotic patients being osteosarcopenic. In a multivariable model, femoral neck BMD was associated with weight, standardised β (St β) 0.29, p = 0.004, ALM St β 0.11, p = 0.03 and Black vs other ethnicities St β 0.19, p = 0.02, and negatively with age St β -0.24, p < 0.001, and frailty St β -2.1, p = 0.04. Z scores (adjusted for gender and age) were associated with ALMI (r = 0.18, p < 0.001).

DISCUSSION

Osteoporosis is increasing with the numbers of elderly dialysis patients. As frailty and sarcopenia increase with age, then the risk of falls and bone fractures increases with osteosarcopenia. Whether interventions with exercise and nutrition can improve bone heath remains to be determined.

Blood Levels of Endocannabinoids, Oxylipins, and Metabolites Are Altered in Hemodialysis Patients

Hemodialysis patients (HDPs) have higher blood pressure, higher levels of inflammation, a higher risk of cardiovascular disease, and unusually low plasma n-3 polyunsaturated fatty acid (PUFA) levels compared to healthy subjects. The objective of our investigation was to examine the levels of endocannabinoids (eCBs) and oxylipins (OxLs) in female HDPs compared to healthy matched female controls, with the underlying hypothesis that differences in specific PUFA levels in hemodialysis patients would result in changes in eCBs and OxLs. Plasma phospholipid fatty acids were analyzed by gas chromatography. Plasma was extracted and analyzed using ultra-performance liquid chromatography followed by electrospray ionization and tandem MS for eCBs and OxLs. The global untargeted metabolite profiling of plasma was performed by GCTOF MS. Compared to the controls, HDPs showed lower levels of plasma EPA and the associated OxL metabolites 5- and 12-HEPE, 14,15-DiHETE, as well as DHA derived 19(20)-EpDPE. Meanwhile, no changes in arachidonylethanolamide or 2-arachidonylglycerol in the open circulation were detected. Higher levels of multiple N-acylethanolamides, monoacylglycerols, biomarkers of progressive kidney disease, the nitric oxide metabolism-linked citrulline, and the uremic toxins kynurenine and creatine were observed in HDP. These metabolic differences in cCBs and OxLs help explain the severe inflammatory and cardiovascular disease manifested by HDPs, and they should be explored in future studies.

A 6-Month clinical practice pilot study of sucroferric oxyhydroxide on nutritional status in patients on peritoneal dialysis

Background

Hyperphosphatemia is common in patients on peritoneal dialysis (PD). Restricting dietary phosphorus often leads to a decrease in protein intake, which may result in hypoalbuminemia. The high pill burden of phosphate binders may also contribute to compromised appetite and dietary intake. Hypoalbuminemia is associated with an increased risk of morbidity and mortality in PD patients. The goal of this study was to determine if sucroferric oxyhydroxide improves albumin and self-reported measures of appetite in PD patients.

Methods

We performed a prospective, open-label, 6-month, pilot study of 17 adult PD patients from the Denver Metro Area. Patients had to use automated peritoneal dialysis for ≥ 3 months, have a serum albumin ≤ 3.8 g/dL, and have serum phosphate ≥ 5.5 mg/dL or ≤ 5.5 mg/dL on a binder other than SO. SO was titrated to a goal serum phosphate of < 5.5 mg/dL. The primary outcome was change in serum phosphate, albumin, and phosphorus-attuned albumin (defined as albumin divided by phosphorus) over 6 months.

Results

The mean (SD) age and dialysis vintage was 55 ± 13 years and 3.8 ± 2.7 years, respectively. Participants’ serum phosphate significantly decreased with fewer phosphate binder pills/day after switching to SO. There was no change in serum albumin, appetite, or dietary intake. However, participants had significant improvements in phosphorus-attuned albumin.

Conclusion

The transition to SO improved phosphorus control, phosphorus-attuned albumin, and pill burden. There were no significant changes in self-reported appetite or dietary intake during the study. These findings suggest that PD patients maintained nutritional status with SO therapy.

Trial registration

First registered at ClinicalTrials.gov (NCT04046263) on 06/08/2019.

Glucose absorption from peritoneal dialysate is associated with a gain in fat mass and a reduction in lean body mass in prevalent peritoneal dialysis patients

The majority of peritoneal dialysates use glucose to generate an osmotic gradient for the convective removal of water and Na. Although glucose can potentially be absorbed, previous studies have failed to establish whether this leads to increased fat weight gain. We measured body composition using bioimpedance in peritoneal dialysis (PD) patients, electively starting PD, attending for their first assessment of peritoneal membrane function after 2-3 months, and then after 12 months. We studied 143 patients: eighty-nine (62·2 %) males, fifty-three (37·1 %) diabetics, mean age 61·3 (SD 14·9) years, with ninety (62·1 %) patients treated by automated PD cyclers with a daytime icodextrin exchange and thirty-seven (25·9 %) by continuous ambulatory PD. Median fat mass increased by 1·8 (-0·5 to 4·1) kg, whereas fat-free mass fell -1·3 (-2·9 to 1·0) kg, and the increase in fat mass was negatively associated with the fall in soft lean mass (r -0·41, P < 0·001). Increased fat mass was associated with measured peritoneal glucose absorption (r 0·69, P < 0·001), and glucose absorption was associated with the amount of 22·7 g/l glucose dialysate (OR 2·0, 95 % CI 1·5, 2·5, P < 0·001), peritoneal urea clearance (OR 9·5, 95 % CI 2·4, 37·1, P = 0·001) and male sex (OR 4·8, 95 % CI 1·5, 14·9, P = 0·008). We report an observational study in prevalent PD patients following body composition from their first assessment of PD membrane function for approximately 12 months, and despite the majority of patients prescribed icodextrin, we have demonstrated not only an association between intra-peritoneal glucose absorption and fat weight gain but also loss of fat-free mass.

Sodium loss, extracellular volume overload and hypertension in peritoneal dialysis patients treated by automated peritoneal dialysis cyclers

INTRODUCTION

Achieving sodium balance is important for peritoneal dialysis patients, as sodium excess may lead to hypertension and extracellular water expansion. We wished to determine whether greater sodium removal had adverse consequences.

METHODS

We calculated 24-h urinary and peritoneal sodium losses in peritoneal dialysis patients treated by automated cyclers, when attending for peritoneal membrane and bioimpedance assessments.

RESULTS

We reviewed 439 peritoneal dialysis patients, 56.7% male, average age 54.6 years, median sodium loss 110 (68-155) mmol/day. Sodium loss was strongly associated with urine volume, r = 0.37, protein nitrogen appearance rate, r = 0.29, and body cell mass, r = 0.21, all p < 0.001. We found no association with blood pressure or anti-hypertensive medication prescription, or extracellular water. On multivariable logistic regression analysis, sodium loss was associated with greater urine output, odds ratio 1.001, 95% confidence interval 1.00-1.001, p < 0.001, and protein nitrogen appearance (odds ratio 1.023, confidence interval 1.006-1.04), p = 0.008. Adjusting for body weight, sodium loss was associated with urine output (odds ratio 1.001, confidence interval 1.001-1.002, p < 0.001), and negatively with body fat index (odds ratio 0.96, confidence interval 0.93-0.99, p = 0.008) and co-morbidity grade (odds ratio 0.58, confidence interval 0.36-0.39, p = 0.023).

CONCLUSION

Heavier peritoneal dialysis patients with greater estimated dietary protein intake (protein nitrogen appearance), those with greater residual renal function and peritoneal clearances, along with lower co-morbidity, had greater daily sodium losses. Adjusting for body weight, then sodium losses were greater with higher daily urine output, and lower in patients with proportionately more body fat and co-morbidity. Sodium losses would appear to primarily determined by body size and not associated with hypertension or extracellular water expansion.

Age modifies the association between serum obestatin, appetite and nutritional status in maintenance hemodialysis patients

BACKGROUND/OBJECTIVES

Increased age is strongly associated with anorexia and protein-energy wasting (PEW) in maintenance hemodialysis (MHD) population. We hypothesized that the association of obestatin, a recently discovered anorexigenic gut hormone, with appetite and nutritional status differs by age groups.

SUBJECTS/METHODS

We performed a cross-sectional study on 261MHD patients. Obestatin, acyl-ghrelin, markers of inflammation (CRP, IL-6, TNF-α) and nutrition (self-reported appetite, dietary intake, biochemical nutritional parameters, and body composition) were measured.

RESULTS

Obestatin was associated with appetite in multivariate analyses even after controlling for such confounders as lean body mass (LBM), IL-6 and acyl-ghrelin in patients younger than 71 years. For each ng/ml increase in obestatin levels, the odds for diminished appetite was 0.75 (95% CI: 0.59-0.96). However, these associations were not observed in patients 71 years and older. Multivariable logistic regression models (including appetite) also showed increasing odds for PEW (defined by ESPEN consensus-based criteria for the diagnosis of malnutrition) across increasing serum obestatin levels (OR: 1.51, 95% CI: 1.05-2.18) in patients 71 years and older. However, after lean body mass (LBM) was added to this model, the association between obestatin and malnutrition was abolished (OR: 1.26, 95% CI: 0.83-1.91).

CONCLUSIONS

The association between serum obestatin, appetite and PEW differs depending on age in MHD patients. A positive link with appetite exists in patients younger than 71 years, whereas this relationship disappears by the age of 71. In older MHD patients, obestatin is associated with PEW through mechanisms related to LBM, but not to appetite.

A patient with CKD and poor nutritional status

Protein energy wasting is common in patients with CKD and ESRD and is associated with adverse clinical outcomes, such as increased rates of hospitalization and death, in these patients. A multitude of factors can affect the nutritional and metabolic status of patients with CKD, including decreased dietary nutrient intake, catabolic effects of renal replacement therapy, systemic inflammation, metabolic and hormonal derangements, and comorbid conditions (such as diabetes and depression). Unique aspects of CKD also confound reliable assessment of nutritional status, further complicating management of this comorbid condition. In patients in whom preventive measures and oral dietary intake from regular meals cannot help them maintain adequate nutritional status, nutritional supplementation, administered orally, enterally, or parenterally, is effective in replenishing protein and energy stores. The advantages of oral nutritional supplements include proven efficacy, safety, and compliance. Anabolic steroids and exercise, with nutritional supplementation or alone, improve protein stores and represent potential additional approaches for the treatment of PEW. There are several emerging novel therapies, such as appetite stimulants, anti-inflammatory interventions, and anabolic agents.

Prevention and treatment of protein energy wasting in chronic kidney disease patients: a consensus statement by the International Society of Renal Nutrition and Metabolism

Protein energy wasting (PEW) is common in patients with chronic kidney disease (CKD) and is associated with adverse clinical outcomes, especially in individuals receiving maintenance dialysis therapy. A multitude of factors can affect the nutritional and metabolic status of CKD patients requiring a combination of therapeutic maneuvers to prevent or reverse protein and energy depletion. These include optimizing dietary nutrient intake, appropriate treatment of metabolic disturbances such as metabolic acidosis, systemic inflammation, and hormonal deficiencies, and prescribing optimized dialytic regimens. In patients where oral dietary intake from regular meals cannot maintain adequate nutritional status, nutritional supplementation, administered orally, enterally, or parenterally, is shown to be effective in replenishing protein and energy stores. In clinical practice, the advantages of oral nutritional supplements include proven efficacy, safety, and compliance. Anabolic strategies such as anabolic steroids, growth hormone, and exercise, in combination with nutritional supplementation or alone, have been shown to improve protein stores and represent potential additional approaches for the treatment of PEW. Appetite stimulants, anti-inflammatory interventions, and newer anabolic agents are emerging as novel therapies. While numerous epidemiological data suggest that an improvement in biomarkers of nutritional status is associated with improved survival, there are no large randomized clinical trials that have tested the effectiveness of nutritional interventions on mortality and morbidity.

Peritoneal dialysis patients have higher prevalence of gastrointestinal symptoms than hemodialysis patients

OBJECTIVE

Malnutrition is common in dialysis patients and is attributed to decreased food intake, and/or chronic systemic inflammation linked to dialysis-related comorbidities and complications. This study aimed to determine the prevalence of gastrointestinal (GI) symptoms in dialysis patients and whether this impacts food intake.

DESIGN

Cross-sectional study.

SETTING

Tertiary teaching hospital.

PARTICIPANTS

All consenting hospital peritoneal dialysis (PD) and hemodialysis (HD) patients.

METHODS

Patients were interviewed by a dietitian regarding the prevalence and impact of GI symptoms (nausea, vomiting, bloating, early satiety, diarrhea, heartburn, fatigue, and weight changes). Serum levels of albumin were measured, and the use of medication known to cause GI symptoms was recorded.

MAIN OUTCOME MEASURE

Presence of GI symptoms.

RESULTS

The PD (n = 122) and HD (n = 172) groups were similar in age, gender, and presence of diabetes. Serum albumin levels were lower for those on PD compared with HD (3.2 vs. 3.5 g/dL, P < .001). Eighty-five percent of the patients on PD reported at least 1 GI symptom, compared with 51% on HD. Compared with HD, more PD patients reported that GI symptoms were related to the onset of dialysis (55% vs. 12%, P < .001). A greater number of PD patients (compared with HD patients) reported a decrease in food intake (53% vs. 14%, P < .001) and that they had attempted dietary changes to alleviate symptoms (34% vs. 9%, P < .001).

CONCLUSION

These results should influence dietetic educational practice. In addition to the provision of adequate protein and energy, dialysis patients should be counselled regarding the management of GI symptoms and monitored for the prevalence and severity of these symptoms.

Appetite and gastrointestinal symptoms in chronic hemodialysis patients

OBJECTIVE

The aim of the present cross-sectional study was to assess the association between self-reported appetite and gastrointestinal symptoms in chronic hemodialysis patients.

DESIGN

A cross-sectional study was carried out.

SETTING

The study was carried out at an outpatient hemodialysis service center.

PATIENTS

A total of 110 patients were included in this study.

INTERVENTION

The first question of the Hemodialysis Study Appetite questionnaire was used to assess the appetite of the HD patients. The multiple-choice answers for the first question "During the past week, how would you rate your appetite?" were as follows: (1) very good, (2) good, (3) fair, (4) poor, or (5) very poor. At the same time, each patient was invited to answer the following questions: Did you have any of the following symptoms (hiccups, feeling full after a few bites of food, nausea, vomiting, indigestion, abdominal pain, bloating, and constipation) in the last 2 weeks? Are there particular foods that you used to like but now do not? Did you have changes in smell in the last 2 weeks? Did you have taste changes in the last 2 weeks?

MAIN OUTCOME MEASURE

Possible associations between appetite and gastrointestinal symptoms were assessed in this study.

RESULTS

In 52 (47.2%) HD patients, the appetite was very good or good (group A), in 28 (25.4%) fair (group B), and in 30 (27.3) poor or very poor (group C). The most frequent symptoms were bloating and constipation. The frequency of food aversion and early satiety were 23.6% and 18.2%, respectively. The frequency of changes in smell and taste were 3.6% and 7.2%, respectively. The frequency of early satiety, food aversion, changes in smell and taste was significantly higher in group C as compared with group A. Similarly, the frequency of early satiety, food aversion, and changes in taste were higher in group B than in group A. The other frequencies did not differ significantly among group A, B, and C.

CONCLUSION

Food aversion, early satiety, changes in taste and smell were significantly more frequent in HD patients with poor or very poor appetite as compared with those with good or very good appetite.

Nutritional Intake in Adult Hemodialysis Patients

BACKGROUND

Research pertaining to the nutritional intake of hemodialysis patients is limited.

PURPOSE

Describe the nutritional quality of foods consumed by hemodialysis patients and variation by day of the week.

METHODS

Dietary recalls were obtained from 22 hemodialysis patients and analyzed using the Nutrition Data System for Research.

RESULTS

Few statistically significant differences were found by day of the week, but several dietary deficits were noted.

CONCLUSION

The data suggest poor intake of calories, protein, and several vitamins and minerals, as well as excess sodium consumption, but little variation by day of the week. Additional research is needed.

Bicarbonate-Based Peritoneal Dialysis Solution has Less Effect on Ingestive Behavior than Lactate-Based Peritoneal Dialysis Solution

Objective

The anorexia seen in peritoneal dialysis (PD) patients may be due partially to factors of dialysis solutions, such as pH and buffering agent. We tested the effects of different PD solutions in an experimental rat model for appetite.

Design

The intraoral intake of a sucrose solution from an implanted intraoral cannula in freely moving male Wistar rats was used to evaluate appetite at 30 minutes and 120 minutes after intraperitoneal (IP) infusion of bicarbonate (25 mmol/L)/lactate (15 mmol/L)-based PD solution (P) and conventional lactate (40 mmol/L)-based PD solution (D) with different concentrations of glucose. We also tested different buffer solutions containing lactate and bicarbonate with different pH but with no glucose.

Results

The IP infusion as such and the 30 mL volume did not inhibit appetite; however, appetite was significantly less inhibited by P than by D in the 1.36%, 2.27%, and 3.86% solutions ( p < 0.05). Furthermore, intraoral intake was significantly higher in rats receiving IP solution with bicarbonate buffer (pH 7.4) than with lactate buffer ( p < 0.05), whereas there was no significant difference in intraoral intake for lactate with pH 5.5, pH 6.6, or pH 7.4.

Conclusions

The bicarbonate/lactate solution inhibited appetite less than the lactate solution; this was due partially to the use of bicarbonate. The results show possible benefit on appetite of reducing the lactate concentration in PD solutions.

Assessment of subjective appetite sensations in hemodialysis patients. Agreement and feasibility between traditional paper and pen and a novel electronic appetite rating system

The aim of this study was to assess the agreement between a novel Electronic Appetite Rating System (EARS) and traditional paper and pen visual analog scales (VASs) in a clinical population. 28 hemodialysis patients (mean age 61+/-17 years, 50% male, median dialysis vintage 19.5(4-101) months) were asked to rate their subjective sensations of hunger, fullness and desire to eat on VAS using both methods. The mean (S.D.) bias ranged from 2.6(16.6)mm to 6.2(15.7)mm which indicated that the two methods did not agree. Patients preferred the paper and pen method compared with the EARS. Either method would be suitable to use in a clinical population; however, it would be inappropriate to use the methods interchangeably.

Single meal food intake characteristics reliably predict nutrition status and body composition in patients undergoing continuous peritoneal dialysis

AIM

This study aimed to determine whether single meal food intake characteristics measured via visual analogue scales (VAS) predict appetite and have a clinical impact on continuous ambulatory peritoneal dialysis (PD) patients.

METHODS

The nutritional status of 50 continuous ambulatory PD patients (30 men, mean age 44.26 +/- 13.53 years, and 20 women, mean age 48.70 +/- 12.53 years) at a single tertiary referral hospital was evaluated via subjective global assessment and VAS questionnaires. The Spearman correlation coefficient was used to evaluate the linear association between continuous variables, while the two-sample Student's t-test was performed to compare ghrelin levels between the two groups. P-values less than 0.05 were considered to be of statistical significance.

RESULTS

Subjective global assessment was correlated with VAS scores in each single patient. VAS score for fullness sensation was significantly positively correlated with age (r = 0.41, P = 0.02), triceps skin fold (r = 0.46, P = 0.01), waist-hip ratio (r = 0.50, P = 0.005) and fat content (r = 0.37, P = 0.04), and significantly negatively correlated with daily energy (r = -0.36, P = 0.04) and protein intake (r = -0.52, P = 0.003). By contrast, serum ghrelin level and the four VAS scores were not correlated.

CONCLUSION

Single meal food intake characteristics can reliably estimate nutrition status and predict body composition in patients undergoing continuous PD.

Polydipsia: a feature of peritoneal dialysis

BACKGROUND

Some dialysis patients fail to comply with their fluid restriction causing problems due to volume overload. These patients sometimes blame excessive thirst. There has been little work in this area and no work documenting polydipsia among peritoneal dialysis (PD) patients.

METHODS

We measured motivation to drink and fluid consumption in 46 haemodialysis patients (HD), 39 PD patients and 42 healthy controls (HC) using a modified palmtop computer to collect visual analogue scores at hourly intervals.

RESULTS

Mean thirst scores were markedly depressed on the dialysis day (day 1) for HD (P<0.0001). The profile for day 2 was similar to that of HC. PD generated consistently higher scores than HD day 1 and HC (P = 0.01 vs. HC and P<0.0001 vs HD day 1). Reported mean daily water consumption was similar for HD and PD with both significantly less than HC (P<0.001 for both). However, measured fluid losses were similar for PD and HC whilst HD were lower (P<0.001 for both) suggesting that the PD group may have underestimated their fluid intake.

CONCLUSION

Our results indicate that HD causes a protracted period of reduced thirst but that the population's thirst perception is similar to HC on the interdialytic day despite a reduced fluid intake. In contrast, the PD group recorded high thirst scores throughout the day and were apparently less compliant with their fluid restriction. This is potentially important because the volume status of PD patients influences their survival.