Effects of Keto Acid Supplements on Chinese Patients Receiving Maintenance Hemodialysis: A Prospective, Randomized, Controlled, Single-Center Clinical Study
Introduction
Chronic kidney disease (CKD) is a global health concern, with dietary management playing a critical role in mitigating complications and improving patient outcomes. Among CKD patients, those undergoing maintenance hemodialysis (MHD) are particularly vulnerable to protein-energy malnutrition, which is associated with increased morbidity, mortality, and reduced quality of life. The National Kidney Foundation’s Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines recommend a dietary protein intake (DPI) of 1.2 g/kg/day and a total energy intake (TEI) of 35 kcal/kg/day for MHD patients. However, adherence to these recommendations is often challenging due to dietary restrictions, anorexia, and socioeconomic factors.
In recent years, low-protein diets supplemented with keto analogs of essential amino acids (KAs) have gained attention for their potential to ameliorate metabolic disturbances in CKD patients and delay dialysis initiation. However, the efficacy of KA supplementation in MHD patients, particularly in Chinese populations with distinct dietary habits and lifestyles, remains unclear. This study aimed to evaluate the effects of KA supplementation on nutritional status, inflammatory markers, and body composition in Chinese MHD patients without malnutrition.
Methods
This prospective, randomized, controlled, single-center clinical study was conducted between 2011 and 2014 at Peking Union Medical College Hospital. Twenty-nine MHD patients were enrolled and randomly assigned to either a control group (n = 14) or a KA group (n = 15). The control group maintained a DPI of 0.9 g/kg/day, while the KA group received an additional KA supplement of 0.1 g/kg/day (Ketosteril®; Fresenius Kabi AG, Germany). Both groups had a TEI of approximately 28 kcal/kg/day.
Nutritional status was assessed using bioelectric impedance analysis (BIA) to measure lean tissue mass (LTM), adipose tissue mass (ATM), and body cell mass. Other parameters included anthropometric measurements (e.g., triceps skin-fold thickness and hand-grip strength), biochemical markers (e.g., albumin, pre-albumin, hemoglobin), inflammatory markers (e.g., high-sensitivity C-reactive protein), and serum amino acid profiles. Dialysis adequacy was evaluated using the Kt/V formula, where K represents dialyzer clearance of urea, t is dialysis time, and V is the volume of urea distribution.
Patients were followed up monthly, and dietary compliance was monitored using 3-day diet diaries. Data were analyzed using Keto Nutritional Assessment software (Fresenius Kabi AG). Statistical analyses were performed using JMP® Pro software, with a significance level set at p < 0.05.
Results
Baseline Characteristics
The study included 15 male and 14 female patients, with no significant differences in age, gender, body mass index (BMI), or dialysis duration between the control and KA groups. Primary diseases leading to CKD included chronic glomerulonephritis, diabetic nephropathy, lupus nephritis, polycystic kidney disease, and drug-induced nephropathy.
Dietary Compliance and Dialysis Adequacy
Both groups maintained similar TEIs (control: 28.04 ± 6.63 kcal/kg/day; KA: 27.68 ± 3.52 kcal/kg/day) and DPIs (control: 0.95 ± 0.26 g/kg/day; KA: 0.96 ± 0.30 g/kg/day) throughout the study. The KA group consumed an additional 0.1 g/kg/day of KAs. Dialysis adequacy, as measured by Kt/V, was comparable between the groups at baseline (control: 1.32 ± 0.22; KA: 1.35 ± 0.17) and after 6 months (control: 1.34 ± 0.25; KA: 1.33 ± 0.25).
Nutritional Assessment
No significant differences were observed in anthropometric parameters, including triceps skin-fold thickness (control: 9.00 mm; KA: 12.00 mm) and hand-grip strength (control: 25.65 kg; KA: 21.10 kg). Biochemical markers such as plasma albumin (control: 40.50 ± 3.70 g/L; KA: 39.07 ± 3.31 g/L), pre-albumin (control: 357.29 ± 95.68 mg/L; KA: 321.67 ± 59.34 mg/L), and hemoglobin (control: 113.64 ± 13.85 g/L; KA: 106.20 ± 17.64 g/L) remained stable in both groups.
Calcium and Phosphorus Metabolism
Serum calcium (control: 2.28 ± 0.23 mmol/L; KA: 2.41 ± 0.17 mmol/L), phosphorus (control: 1.90 ± 0.69 mmol/L; KA: 1.74 ± 0.51 mmol/L), and parathyroid hormone levels (control: 362.00 ng/L; KA: 236.00 ng/L) showed no significant differences between the groups.
Inflammatory Parameters and Lipid Profiles
High-sensitivity C-reactive protein (control: 2.04 mg/L; KA: 3.35 mg/L), low-density lipoprotein cholesterol (control: 2.52 ± 0.79 mmol/L; KA: 2.30 ± 0.75 mmol/L), and lipoprotein(a) levels (control: 133.50 mg/L; KA: 150.00 mg/L) were similar in both groups.
Bioelectric Impedance Analysis
BIA parameters, including LTM (control: 35.60 ± 10.28 kg; KA: 32.76 ± 8.82 kg), ATM (control: 28.86 ± 11.41 kg; KA: 32.09 ± 11.48 kg), and body cell mass (control: 19.31 ± 7.10 kg; KA: 17.31 ± 5.78 kg), showed no significant changes over the study period.
Amino Acid Profiles
The essential amino acid/non-essential amino acid ratio did not differ significantly between the groups at baseline (control: 0.73; KA: 0.76), after 3 months (control: 0.81; KA: 0.65), or after 6 months (control: 0.77; KA: 0.71).
Discussion
This study demonstrated that Chinese MHD patients with a DPI of 0.9 g/kg/day and a TEI of approximately 28 kcal/kg/day maintained stable nutritional status over a 6-month period. The addition of KA supplements (0.1 g/kg/day) did not significantly improve nutritional parameters, inflammatory markers, or body composition. These findings suggest that the recommended DPI and TEI in current guidelines may not be universally applicable, particularly for Asian populations with distinct dietary habits.
The lack of significant benefits from KA supplementation may be attributed to the relatively low dose administered, the short study duration, or the small sample size. Additionally, the absence of changes in amino acid profiles and inflammatory markers indicates that KA supplementation at this dosage may not be sufficient to influence metabolic pathways or inflammatory responses in MHD patients.
Limitations
This study has several limitations. The sample size was relatively small, and the study duration was short for observing long-term nutritional outcomes. Dietary compliance was monitored using 3-day diet diaries, which may not fully capture daily variations in intake. Furthermore, the study did not assess the impact of KA supplementation on residual renal function, which could provide additional insights into its potential benefits.
Conclusion
In conclusion, Chinese MHD patients with a DPI of 0.9 g/kg/day and a TEI of approximately 28 kcal/kg/day maintained stable nutritional status over a 6-month period. The addition of KA supplements (0.1 g/kg/day) did not provide significant benefits in terms of nutritional parameters, inflammatory markers, or body composition. These findings highlight the need for individualized dietary recommendations based on patient-specific factors, including lifestyle, dietary preferences, and comorbidities. Further research with larger sample sizes and longer follow-up periods is needed to evaluate the potential benefits of KA supplementation in MHD patients.
doi.org/10.1097/CM9.0000000000000578
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