Using Bioimpedance Spectroscopy for Diagnosis of Malnutrition in Chronic Kidney Disease Stage 5-Is It Useful?

OBJECTIVE: Malnutrition is common in chronic kidney disease stage 5 (CKD5) and has negative clinical impacts. The aim of the present study is to evaluate bioimpedance spectroscopy (BIS) in diagnosing malnutrition in CKD5 including hemodialysis and peritoneal dialysis patients (CKD5D) using cutoff values for fat-free mass index (FFMI) according to the Global Leadership Initiative on Malnutrition criteria. Dual-energy X-ray absorptiometry (DXA) was used as a reference method. DESIGN AND METHODS: We performed a single-center cross-sectional diagnostic study of 90 patients with CKD5 or CKD5D. RESULTS: BIS-derived FFMI estimates were significantly higher compared with those obtained by DXA (18.5 ± 2.6 vs.17.8 ± 2.0, P < .05). The mean difference in FFMI estimates between the methods (DXA-BIS) and Bland-Altman 95% limits of agreements is -0.38 (2.76, -3.52) kg/m2. Overhydration (B = 0.67, P < .001), age (B = 0.02, P = .037), and interactions between overhydration and CKD5 subgroups (P = .034) independently predicted bias in BIS-derived FFMI. BIS-derived FFMI showed poor sensitivity (64%) and positive predictive value (48%) in diagnosing malnutrition in the present study population. CONCLUSION: The present study showed a limited agreement between estimates of FFMI derived by BIS and DXA due to a large interindividual variation. Using BIS as a clinical tool for assessing FFMI has limited accuracy and poor sensitivity in diagnosing malnutrition in patients with CKD5 and CKD5D.

A practical approach to low protein diets in Sweden- 45 years of clinical use.

This review provides an overview of the development, implementation and practise of low protein diets (LPD) in Sweden. While the current practice is discussed in general terms emphasizing the interplay between nephrologists and dieticians, the "self-selected" LPD model is explained as a practical approach to facilitated patient's adherence to the nutritional therapy. This model is currently implemented in most clinics of the country and gives considerable flexibility regarding variation in meal planning, food selection, amounts consumed, cooking methods as well as adaptations to day-to-day changes. Current LPD use in Sweden is presented through analysis of the Swedish Renal Registry. Finally two patient cases are illustrated, with examples on their diets, attempts to reduce the protein content to the desired thresholds and their clinical course.

Positive effects of protein restriction in patients with chronic kidney disease.

OBJECTIVES: The potential benefit or harm of low-protein diets (LPDs) for patients with chronic kidney disease has been debated. This study sought to investigate the effects of treatment with LPDs on nutritional markers, morbidity, and survival during subsequent dialysis. A second objective was to evaluate the effect of LPDs on renal function and the start of dialysis. DESIGN: This was a retrospective study of medical records. SETTING: The setting was an outpatient nephrology and dialysis clinic. PATIENTS: One-hundred twenty-two renal patients were recruited from the central dialysis registry of one clinic. The patients had been followed by a nephrologist for > or =6 months before dialysis. Sixty-one patients were treated with LPDs, and an equal number of control patients not treated with LPDs were matched for sex, age, dialysis modality, diabetes, and start of dialysis. MAIN OUTCOME MEASURES: Main outcome measures included weight and weight change, serum albumin, glomerular filtration rate, morbidity, and mortality. RESULTS: There was less mean weight loss in the LPD group the year before dialysis (0.14 kg/month, compared with the control group at 0.36 kg/month, P < .05). The level of serum albumin was higher in the LPD group at the start of dialysis (P < .01). The mean rate of progression during the 6 months before dialysis was lower in the LPD group (4.1 mL/min/year) than in the control group (13.4 mL/min/year) (P < .001). The LPD group had fewer days of hospitalization at the start of dialysis than the control group (8.2 vs 15.4 days, respectively, P < .01). There was no difference in mortality between groups 1, 2, or 5 years after starting dialysis. CONCLUSIONS: Low-protein diets can reduce patient morbidity, preserve renal function, relieve uremic symptoms and improve nutritional status. The results suggest that LPDs can postpone the start of dialysis for 6 months, and entail substantial cost-savings. Low-protein diets should be used more generally in the renal community.

Protein restriction and body composition in renal disease.

OBJECTIVE: To study the effect of low-protein diet (LPD) on body composition (BC). STUDY DESIGN: A systematic review of the literature investigating BC during LPD treatment using total body potassium, dual energy X-ray absorptiometry, bioelectrical impedance analysis, and anthropometry. PATIENTS: Studies reporting data of patients treated with LPD 0.3-0.75 g/kg/day and a renal function of glomerular filtration rate (GFR) < or =20 mL/min, creatinine clearance < or =25 mL/min, on serum creatinine > or =500 micromol/L were included in the review. Fourteen studies with a total number of 666 subjects were found eligible. RESULTS: All studies except two concluded that treatment with LPD does not affect BC negatively. However, LPD should not be introduced in patients with a complicating disease, e.g., acidosis, septicaemia, and surgical treatment; neither should it be continued in patients who are unable to adhere to a diet prescription. Furthermore, LPD should be introduced with great caution in patients with an expected time to dialysis of < or =4 months due to an initial reduction of body weight and/or fat-free mass. Monitoring of treatment with LPD must be emphasized, including BC measurements and evaluation of protein and energy intake. These conclusions do not apply to patients with diabetes mellitus, because this diagnosis was excluded in a majority of reviewed studies. CONCLUSION: There is no strong evidence that LPD impairs BC in patients with GFR < or =20 mL/min.