Levocarnitine and Dialysis: A Review

Peritoneal dialysis fluids

There have been significant advances in the understanding of peritoneal dialysis (PD) in the last 40 years, and uptake of PD as a modality of kidney replacement therapy is increasing worldwide. PD fluids, therefore, remains the lifeline for patients on this treatment. Developing these fluids to be efficacious in solute clearance and ultrafiltration, with minimal adverse consequences to peritoneal membrane health and systemic effects is a key requirement. Since the first PD fluid produced in 1959, modifications to PD fluids have been made. Nonetheless, the search for that ideal PD fluid remains elusive. Understanding the components of PD fluids is a key aspect of optimizing the successful delivery of PD, allowing for individualized PD prescription. Glucose remains an integral component of PD fluids; however, its deleterious effects continue to be the impetus for the search of an alternative osmotic agent, and icodextrin remains the main alternative. More biocompatible PD fluids have been developed and have shown benefits in preserving residual kidney function. However, high cost and reduced accessibility remain deterrents to its widespread clinical use in many countries. Large-scale clinical trials are necessary and very much awaited to improve the narrow spectrum of PD fluids available for clinical use.

Acetyl-L-carnitine and Amyotrophic Lateral Sclerosis: Current Evidence and Potential use

BACKGROUND

The management of neurodegenerative diseases can be frustrating for clinicians, given the limited progress of conventional medicine in this context.

AIM

For this reason, a more comprehensive, integrative approach is urgently needed. Among various emerging focuses for intervention, the modulation of central nervous system energetics, oxidative stress, and inflammation is becoming more and more promising.

METHODS

In particular, electrons leakage involved in the mitochondrial energetics can generate reactive oxygen-free radical-related mitochondrial dysfunction that would contribute to the etiopathology of many disorders, such as Alzheimer's and other dementias, Parkinson's disease, multiple sclerosis, stroke, and amyotrophic lateral sclerosis (ALS).

RESULTS

In this context, using agents, like acetyl L-carnitine (ALCAR), provides mitochondrial support, reduces oxidative stress, and improves synaptic transmission.

CONCLUSION

This narrative review aims to update the existing literature on ALCAR molecular profile, tolerability, and translational clinical potential use in neurodegeneration, focusing on ALS.

Interventions for fatigue in people with kidney failure requiring dialysis

BACKGROUND

Fatigue is a common and debilitating symptom in people receiving dialysis that is associated with an increased risk of death, cardiovascular disease and depression. Fatigue can also impair quality of life (QoL) and the ability to participate in daily activities. Fatigue has been established by patients, caregivers and health professionals as a core outcome for haemodialysis (HD).

OBJECTIVES

We aimed to evaluate the effects of pharmacological and non-pharmacological interventions on fatigue in people with kidney failure receiving dialysis, including HD and peritoneal dialysis (PD), including any setting and frequency of the dialysis treatment.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 18 October 2022 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Studies evaluating pharmacological and non-pharmacological interventions affecting levels of fatigue or fatigue-related outcomes in people receiving dialysis were included. Studies were eligible if fatigue or fatigue-related outcomes were reported as a primary or secondary outcome. Any mode, frequency, prescription, and duration of therapy were considered.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted data and assessed the risk of bias. Treatment estimates were summarised using random effects meta-analysis and expressed as a risk ratio (RR) or mean difference (MD), with a corresponding 95% confidence interval (CI) or standardised MD (SMD) if different scales were used. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Ninety-four studies involving 8191 randomised participants were eligible. Pharmacological and non-pharmacological interventions were compared either to placebo or control, or to another pharmacological or non-pharmacological intervention. In the majority of domains, risks of bias in the included studies were unclear or high. In low certainty evidence, when compared to control, exercise may improve fatigue (4 studies, 217 participants (Iowa Fatigue Scale, Modified Fatigue Impact Scale, Piper Fatigue Scale (PFS), or Haemodialysis-Related Fatigue scale score): SMD -1.18, 95% CI -2.04 to -0.31; I2 = 87%) in HD. In low certainty evidence, when compared to placebo or standard care, aromatherapy may improve fatigue (7 studies, 542 participants (Fatigue Severity Scale (FSS), Rhoten Fatigue Scale (RFS), PFS or Brief Fatigue Inventory score): SMD -1.23, 95% CI -1.96 to -0.50; I2 = 93%) in HD. In low certainty evidence, when compared to no intervention, massage may improve fatigue (7 studies, 657 participants (FSS, RFS, PFS or Visual Analogue Scale (VAS) score): SMD -1.06, 95% CI -1.47, -0.65; I2 = 81%) and increase energy (2 studies, 152 participants (VAS score): MD 4.87, 95% CI 1.69 to 8.06, I2 = 59%) in HD. In low certainty evidence, when compared to placebo or control, acupressure may reduce fatigue (6 studies, 459 participants (PFS score, revised PFS, or Fatigue Index): SMD -0.64, 95% CI -1.03 to -0.25; I2 = 75%) in HD. A wide range of heterogenous interventions and fatigue-related outcomes were reported for exercise, aromatherapy, massage and acupressure, preventing our capability to pool and analyse the data. Due to the paucity of studies, the effects of pharmacological and other non-pharmacological interventions on fatigue or fatigue-related outcomes, including non-physiological neutral amino acid, relaxation with or without music therapy, meditation, exercise with nandrolone, nutritional supplementation, cognitive-behavioural therapy, ESAs, frequent HD sections, home blood pressure monitoring, blood flow rate reduction, serotonin reuptake inhibitor, beta-blockers, anabolic steroids, glucose-enriched dialysate, or light therapy, were very uncertain. The effects of pharmacological and non-pharmacological treatments on death, cardiovascular diseases, vascular access, QoL, depression, anxiety, hypertension or diabetes were sparse. No studies assessed tiredness, exhaustion or asthenia. Adverse events were rarely and inconsistently reported.

AUTHORS' CONCLUSIONS

Exercise, aromatherapy, massage and acupressure may improve fatigue compared to placebo, standard care or no intervention. Pharmacological and other non-pharmacological interventions had uncertain effects on fatigue or fatigue-related outcomes in people receiving dialysis. Future adequately powered, high-quality studies are likely to change the estimated effects of interventions for fatigue and fatigue-related outcomes in people receiving dialysis.

Xanthine-derived reactive oxygen species exacerbates adipose tissue disorders in male db/db mice induced by real-ambient PM2.5 exposure

Epidemiological and experimental data have associated exposure to fine particulate matter (PM2.5) with various metabolic dysfunctions and diseases, including overweight and type 2 diabetes. Adipose tissue is an energy pool for storing lipids, a necessary regulator of glucose homeostasis, and an active endocrine organ, playing an essential role in developing various related diseases such as diabetes and obesity. However, the molecular mechanisms underlying PM2.5-impaired functions in adipose tissue have rarely been explored. In this work, metabolomics based on liquid chromatography-mass spectrometry was performed to study the adverse impacts of PM2.5 exposure on brown adipose tissue (BAT) and white adipose tissue (WAT) in the diabetic mouse model. We found the effects of PM2.5 exposure by comparing the different metabolites in both adipose tissues of male db/db mice using real-ambient PM2.5 exposure. The results showed that PM2.5 exposure changed the purine metabolism in mice, especially the dramatic increase of xanthine content in both WAT and BAT. These changes led to significant oxidative stress. Then the results from real-time quantitative polymerase chain reaction showed that PM2.5 exposure could cause the production of inflammatory factors in both adipose tissues. Moreover, the increased reactive oxygen species (ROS) promoted triglyceride accumulation in WAT and inhibited its decomposition, causing increased WAT content in db/db mice. In addition, PM2.5 exposure significantly suppressed thermogenesis and affected energy metabolism in the BAT of male db/db mice, which may deteriorate insulin sensitivity and blood glucose regulation. This research demonstrated the impact of PM2.5 on the adipose tissue of male db/db mice, which may be necessary for public health.

Comparison of Local Metabolic Changes in Diabetic Rodent Kidneys Using Mass Spectrometry Imaging

Understanding the renal region-specific metabolic alteration in different animal models of diabetic nephropathy (DN) is critical for uncovering the underlying mechanisms and for developing effective treatments. In the present study, spatially resolved metabolomics based on air flow-assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI) was used to compare the local metabolic changes in the kidneys of HFD/STZ-induced diabetic rats and db/db mice. As a result, a total of 67 and 59 discriminating metabolites were identified and visualized in the kidneys of the HFD/STZ-induced diabetic rats and db/db mice, respectively. The result showed that there were significant region-specific changes in the glycolysis, TCA cycle, lipid metabolism, carnitine metabolism, choline metabolism, and purine metabolism in both DN models. However, the regional levels of the ten metabolites, including glucose, AMP, eicosenoic acid, eicosapentaenoic acid, Phosphatidylserine (36:1), Phosphatidylserine (36:4), Phosphatidylethanolamine (34:1), Phosphatidylethanolamine (36:4), Phosphatidylcholine (34:2), Phosphatidylinositol (38:5) were changed in reversed directions, indicating significant differences in the local metabolic phenotypes of these two commonly used DN animal models. This study provides comprehensive and in-depth analysis of the differences in the tissue and molecular pathological features in diabetic kidney injury in HFD/STZ-induced diabetic rats and db/db mice.

Carnitine supplements for people with chronic kidney disease requiring dialysis

BACKGROUND

Carnitine deficiency is common in patients with chronic kidney disease (CKD) who require dialysis. Several clinical studies have suggested that carnitine supplementation is beneficial for dialysis-related symptoms. However, the clinical effectiveness and potential adverse effects of carnitine supplementation in dialysis patients have not been determined.

OBJECTIVES

This review aimed to evaluate the effectiveness and safety of carnitine supplementation for the treatment of dialysis-related complications in CKD patients requiring dialysis.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 16 August 2022 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) and quasi-RCTs (RCTs in which allocation to treatment was obtained by alternation, use of alternate medical records, date of birth, or other predictable methods) that compared carnitine supplements with placebo or standard care in people with CKD requiring dialysis.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted study data and assessed study quality. We used a random-effects model to perform a quantitative synthesis of the data.  We used the I² statistic to measure heterogeneity amongst the studies in each analysis. We indicated summary estimates as a risk ratio (RR) for dichotomous outcomes, mean difference (MD) for continuous outcomes, or standardised mean differences (SMD) if different scales were used, with 95% confidence intervals (CI). We assessed the certainty of the evidence for each of the main outcomes using the GRADE (Grades of Recommendation, Assessment, Development, and Evaluation) approach.

MAIN RESULTS

We included 52 studies (47 parallel RCTs and five cross-over RCTs) (3398 randomised participants). All studies compared L-carnitine with a placebo, other treatment, or no treatment. Standard care was continued as co-interventions in each group. Most studies were judged to have an unclear or high risk of bias. L-carnitine may have little or no effect on the quality of life (QoL) SF-36 physical component score (PCS) (4 studies, 134 participants: SMD 0.57, 95% CI -0.15 to 1.28; I² = 73%; low certainty of evidence), and the total QoL score (Kidney Disease Quality of Life (KDQOL), VAS (general well-being), or PedsQL) (3 studies, 230 participants: SMD -0.02, 95% CI -0.29 to 0.25; I² = 0%; low certainty of evidence). L-carnitine may improve SF-36 mental component score (MCS) (4 studies, 134 participants: SMD 0.70, 95% CI 0.22 to 1.18; I² = 42%; low certainty of evidence). L-carnitine may have little or no effect on fatigue score (2 studies, 353 participants: SMD 0.01, 95% CI -0.20 to 0.23; I² = 0%; low certainty of evidence), adverse events (12 studies, 1041 participants: RR, 1.14, 95% CI 0.86 to 1.51; I² = 0%; low certainty of evidence), muscle cramps (2 studies, 102 participants: RR, 0.44, 95% CI 0.18 to 1.09; I² = 23%; low certainty of evidence), and intradialytic hypotension (3 studies, 128 participants: RR, 0.76, 95% CI 0.34 to 1.69; I² = 0%; low certainty of evidence). L-carnitine may improve haemoglobin levels (26 studies, 1795 participants: MD 0.46 g/dL, 95% CI 0.18 to 0.74; I² = 86%; low certainty of evidence) and haematocrit values (14 studies, 950 participants: MD 1.78%, 95% CI 0.38 to 3.18; I² = 84%; low certainty of evidence).

AUTHORS' CONCLUSIONS

The available evidence does not currently support the use of carnitine supplementation in the treatment of dialysis-related carnitine deficiency. Although carnitine supplementation may slightly improve anaemia-related markers, carnitine supplementation makes little or no difference to adverse events. However, these conclusions are based on limited data and, therefore, should be interpreted with caution.

Carnitine Deficiency after Long-Term Continuous Renal Replacement Therapy

A 60-year-old man was admitted in the intensive care unit (ICU) for a rapidly progressive respiratory failure due to SARS-CoV-2 infection. He developed numerous complications including acute kidney injury (AKI) requiring prolonged continuous renal replacement therapy (CRRT). Enteral feeding was initiated on day 8. Despite nutritional management, there was a remarkable amyotrophy and weight loss. On day 85 in the ICU, the patient became progressively unresponsive. An extensive metabolic workup was performed, and blood results showed hyperammoniemia and hypertriglyceridemia. Plasma free carnitine level was low, as was also copper. After carnitine supplementation, the neurological condition rapidly improved, and metabolic perturbations regressed. Prolonged CRRT may be complicated by clinically significant deficiency in micronutrients and trace elements.

The effect of levocarnitine supplementation on dialysis-related hypotension: A systematic review, meta-analysis, and trial sequential analysis

BACKGROUND

Dialysis patients have been shown to have low serum carnitine due to poor nutrition, deprivation of endogenous synthesis from kidneys, and removal by hemodialysis. Carnitine deficiency leads to impaired cardiac function and dialysis-related hypotension which are associated with increased mortality. Supplementing with levocarnitine among hemodialysis patients may diminish incidence of intradialytic hypotension. Data on this topic, however, lacks consensus.

METHODS

We conducted electronic searches in PubMed, Embase and Cochrane Central Register of Controlled Trials from January 1960 to 19th November 2021 to identify randomized controlled studies (RCTs), which examined the effects of oral or intravenous levocarnitine (L-carnitine) on dialysis-related hypotension among hemodialysis patients. The secondary outcome was muscle cramps. Study results were pooled and analyzed utilizing the random-effects model. Trial sequential analysis (TSA) was performed to assess the strength of current evidence.

RESULTS

Eight trials with 224 participants were included in our meta-analysis. Compared to control group, L-carnitine reduced the incidence of dialysis-related hypotension among hemodialysis patients (pooled OR = 0.26, 95% CI [0.10-0.72], p = 0.01, I2 = 76.0%). TSA demonstrated that the evidence was sufficient to conclude the finding. Five studies with 147 participants showed a reduction in the incidence of muscle cramps with L-carnitine group (pooled OR = 0.22, 95% CI [0.06-0.81], p = 0.02, I2 = 74.7%). However, TSA suggested that further high-quality studies were required. Subgroup analysis on the route of supplementation revealed that only oral but not intravenous L-carnitine significantly reduced dialysis-related hypotension. Regarding dose and duration of L-carnitine supplementation, the dose > 4,200 mg/week and duration of at least 12 weeks appeared to prevent dialysis-related hypotension.

CONCLUSION

Supplementing oral L-carnitine for at least three months above 4,200 mg/week helps prevent dialysis-related hypotension. L-carnitine supplementation may ameliorate muscle cramps. Further well-powered studies are required to conclude this benefit.

Levocarnitine supplementation for management of hypertriglyceridemia in patients receiving parenteral nutrition

BACKGROUND

Levocarnitine deficiency has been observed in patients receiving parenteral nutrition (PN) and can cause or worsen hypertriglyceridemia. The objective was to characterize use of levocarnitine supplementation in PN and evaluate its effect on triglyceride levels in hospitalized adults.

METHODS

This retrospective, single-center study included patients with triglyceride levels ≥175 mg/dl while receiving PN who had a subsequent reduction in lipid injectable emulsion dose. A piecewise linear regression was used to evaluate trends in triglyceride levels before and after the intervention, defined as initiation of levocarnitine in PN for the levocarnitine group, or reduction in lipid injectable emulsion alone for the control group.

RESULTS

Two hundred sixty-one patients who received PN had an elevated triglyceride level and lipid injectable emulsion dose reduction, of which 97 (37.2%) received levocarnitine in PN. The median (IQR) levocarnitine dose added to PN was 8.0 (5.7-9.9) mg/kg. Triglyceride levels at 30 days post-intervention did not differ between groups (125 vs 176 mg/dl, P = .345). The addition of levocarnitine to PN was associated with a significantly greater rate of reduction in triglyceride levels pre-intervention to post-intervention compared with a reduction in lipid injectable emulsion alone (-11 vs -3 mg/dl per day; 95% CI, -15 to -2; P = .012).

CONCLUSION

In hospitalized adults with hypertriglyceridemia who had a lipid injectable emulsion dose reduction, the addition of levocarnitine in PN was not associated with a difference in triglyceride levels at 30 days; however, a greater rate of improvement in pre-intervention to post-intervention triglyceride levels was observed.

Nutrients and micronutrients at risk during renal replacement therapy: a scoping review

PURPOSE OF REVIEW

Malnutrition is frequent in patients with acute kidney injury. Nutrient clearance during renal replacement therapy (RRT) potentially contributes to this complication. Although losses of amino acid, trace elements and vitamins have been described, there is no clear guidance regarding the role of micronutrient supplementation.

RECENT FINDINGS

A scoping review was conducted with the aim to review the existing literature on micronutrients status during RRT: 35 publications including data on effluent losses and blood concentrations were considered relevant and analysed. For completeness, we also included data on amino acids. Among trace elements, negative balances have been shown for copper and selenium: low blood levels seem to indicate potential deficiency. Smaller size water soluble vitamins were found in the effluent, but not larger size liposoluble vitamins. Low blood values were frequently reported for thiamine, folate and vitamin C, as well as for carnitine. All amino acids were detectable in effluent fluid. Duration of RRT was associated with decreasing blood values.

SUMMARY

Losses of several micronutrients and amino acids associated with low blood levels represent a real risk of deficiency for vitamins B1 and C, copper and selenium: they should be monitored in prolonged RRT. Further Research is urgently required as the data are insufficient to generate strong conclusions and prescription recommendations for clinical practice.

Spatially Resolved Metabolomics Based on Air-Flow-Assisted Desorption Electrospray Ionization-Mass Spectrometry Imaging Reveals Region-Specific Metabolic Alterations in Diabetic Encephalopathy

Spatially resolved metabolic profiling of brain is vital for elucidating tissue-specific molecular histology and pathology underlying diabetic encephalopathy (DE). In this study, a spatially resolved metabolomic method based on air-flow-assisted desorption electrospray ionization-mass spectrometry imaging (AFADESI-MSI) was developed for investigating the region-specific metabolic disturbances in the brain of DE model rats induced by a high-fat diet in combination with streptozotocin administration. A total of 19 discriminating metabolites associated with glycolysis and the pentose phosphate pathway (PPP); the glutamate/gamma aminobutyric acid-glutamine cycle and tricarboxylic acid cycle; nucleotide metabolism; lipid metabolism; carnitine homeostasis; and taurine, ascorbic acid, histidine, and choline metabolism were identified and located in the brains of the diabetic rats simultaneously for the first time. The results indicated that increased glycolytic and PPP activity; dysfunction of mitochondrial metabolism; dysregulation of adenosinergic, glutamatergic, dopaminergic, cholinergic, and histaminergic systems; disorder of osmotic regulation and antioxidant system; and disorder of lipid metabolism occur in a region-specific fashion in the brains of DE rats. Thus, this study provides valuable information regarding the molecular pathological signature of DE. These findings also underline the high potential of AFADESI-MSI for applications in various central nervous system diseases.

Effect of levocarnitine supplementation on myocardial strain in children with acute kidney injury receiving continuous kidney replacement therapy: a pilot study

BACKGROUND

Carnitine plays a key role in energy production in the myocardium and is efficiently removed by continuous kidney replacement therapy (CKRT). Effects of levocarnitine supplementation on myocardial function in children receiving CKRT have not been investigated.

METHODS

This controlled pilot cohort study of 48 children investigated effects of levocarnitine supplementation on myocardial strain in children receiving CKRT for acute kidney injury (AKI). Children (n = 9) with AKI had total (TC) and free plasma carnitine (FC) measurements and echocardiogram for longitudinal and circumferential strain at baseline (prior to CKRT) and follow-up (on CKRT for > 1 week with intravenous levocarnitine supplementation, 20 mg/kg/day). Intervention group was compared with three controls: (1) CKRT controls (n = 10) received CKRT > 1 week (+AKI, no levocarnitine), (2) ICU controls (n = 9) were parenteral nutrition-dependent for > 1 week (no AKI, no levocarnitine), and (3) healthy controls (n = 20).

RESULTS

In the Intervention group, TC and FC increased from 36.0 and 18 μmol/L to 93.5 and 74.5 μmol/L after supplementation. TC and FC of unsupplemented CKRT controls declined from 27.2 and 18.6 μmol/L to 12.4 and 6.6 μmol/L, which was lower vs. ICU controls (TC 32.0, FC 26.0 μmol/L), p < 0.05. Longitudinal and circumferential strain of the Intervention group improved from - 18.5% and - 18.3% to - 21.1% and - 27.6% after levocarnitine supplementation; strain of CKRT controls (-14.4%, -20%) remained impaired and was lower vs. Intervention and Healthy Control groups at follow-up, p < 0.05.

CONCLUSIONS

Levocarnitine supplementation is associated with repletion of plasma carnitine and improvement in myocardial strain and may benefit pediatric patients undergoing prolonged CKRT.

Significance of Levocarnitine Treatment in Dialysis Patients

Carnitine is a naturally occurring amino acid derivative that is involved in the transport of long-chain fatty acids to the mitochondrial matrix. There, these substrates undergo β-oxidation, producing energy. The major sources of carnitine are dietary intake, although carnitine is also endogenously synthesized in the liver and kidney. However, in patients on dialysis, serum carnitine levels progressively fall due to restricted dietary intake and deprivation of endogenous synthesis in the kidney. Furthermore, serum-free carnitine is removed by hemodialysis treatment because the molecular weight of carnitine is small (161 Da) and its protein binding rates are very low. Therefore, the dialysis procedure is a major cause of carnitine deficiency in patients undergoing hemodialysis. This deficiency may contribute to several clinical disorders in such patients. Symptoms of dialysis-related carnitine deficiency include erythropoiesis-stimulating agent-resistant anemia, myopathy, muscle weakness, and intradialytic muscle cramps and hypotension. However, levocarnitine administration might replenish the free carnitine and help to increase carnitine levels in muscle. This article reviews the previous research into levocarnitine therapy in patients on maintenance dialysis for the treatment of renal anemia, cardiac dysfunction, dyslipidemia, and muscle and dialytic symptoms, and it examines the efficacy of the therapeutic approach and related issues.

Effects of L-Carnitine Supplementation in Patients Receiving Hemodialysis or Peritoneal Dialysis

L-carnitine is an important factor in fatty acid metabolism, and carnitine deficiency is common in dialysis patients. This study evaluated whether L-carnitine supplementation improved muscle spasm, cardiac function, and renal anemia in dialysis patients. Eighty Japanese outpatients (62 hemodialysis (HD) patients and 18 peritoneal dialysis (PD) patients) received oral L-carnitine (600 mg/day) for 12 months; the HD patients further received intravenous L-carnitine injections (1000 mg three times/week) for 12 months, amounting to 24 months of treatment. Muscle spasm incidence was assessed using a questionnaire, and cardiac function was assessed using echocardiography. Baseline free carnitine concentrations were relatively low in patients who underwent dialysis for >4 years. Total carnitine serum concentration, free carnitine, and acylcarnitine significantly increased after oral L-carnitine treatment for 12 months, and after intravenous L-carnitine injection. There was no significant improvement in muscle spasms, although decreased muscle cramping after L-carnitine treatment was reported by 31% of patients who had undergone HD for >4 years. Hemoglobin concentrations increased significantly at 12 and 24 months in the HD group. Therefore, L-carnitine may be effective for reducing muscle cramping and improving hemoglobin levels in dialysis patients, especially those who have been undergoing dialysis for >4 years.

Skeletal muscle volume loss among liver cirrhosis patients receiving levocarnitine predicts poor prognosis

Sarcopenia has a negative impact on the prognosis of patients with liver cirrhosis (LC). We investigated the significance of skeletal muscle volume and its changes in LC patients taking levocarnitine (L-carnitine).We retrospectively analyzed 51 LC patients taking L-carnitine from December 2012 to March 2019. Skeletal mass index was calculated as the left-right sum of the major × minor axis of psoas muscle at the third lumbar vertebra, divided by height squared (psoas muscle index [PMI]). Patients were classified into 2 groups (low and normal PMI) depending on PMI < 6.0 and < 3.4 cm/m for men and women, respectively. Changes in PMI per month during L-carnitine administration (ΔPMI/m) were calculated, and we classified the patients into 2 groups (severe and mild muscle atrophy) depending on ΔPMI/m below the lower quartile. We assessed overall survival (OS).At the start of L-carnitine administration, there were no significant differences in OS between groups with low and normal PMI. Multivariate analysis showed that ΔPMI/m (hazard ratio [HR], 0.007; P = .005) and L-carnitine administration period (HR, 0.956; P = .021) were significantly associated with OS. Patients with severe muscle atrophy had a significantly lower OS than those with mild muscle atrophy. There was the positive correlation relationship between ΔPMI/m and L-carnitine administration period.Among LC patients taking L-carnitine, progressive muscle volume loss was a predictor of poor prognosis. L-carnitine administration for longer may be able to prevent muscle volume loss and lead to a better prognosis in LC patients.

Kidney disease and organ transplantation in methylmalonic acidaemia

OBJECTIVES

MMA is associated with chronic tubulointerstitial nephritis and a progressive decline in GFR. Optimal management of these children is uncertain. Our objectives were to document the pre-, peri-, and post-transplant course of all children with MMA who underwent liver or combined liver-kidney transplant in our centers.

DESIGN AND METHODS

Retrospective chart review of all cases of MMA who underwent organ transplantation over the last 10 years.

RESULTS

Five children with MMA underwent liver transplant (4/5) and combined liver-kidney transplant (1/5). Three were Mut⁰ and two had a cobalamin B disorder. Four of five were transplanted between ages 3 and 5 years. Renal dysfunction prior to transplant was seen in 2/5 patients. Post-transplant (one liver transplant and one combined transplant) renal function improved slightly when using creatinine-based GFR formula. We noticed in 2 patients a big discrepancy between creatinine- and cystatin C-based GFR calculations. One patient with no renal disease developed renal failure post-liver transplantation. Serum MMA levels have decreased in all to <300 μmol/L. Four patients remain on low protein diet, carnitine, coenzyme Q, and vitamin E post-transplant.

CONCLUSIONS

MMA is a complex metabolic disorder. Renal disease can continue to progress post-liver transplant and close follow-up is warranted. More research is needed to clarify best screening GFR method in patients with MMA. Whether liver transplant alone, continued protein restriction, or the addition of antioxidants post-transplant can halt the progression of renal disease remains unclear.

Efficacy of L-carnitine supplementation for improving lean body mass and physical function in patients on hemodialysis: a randomized controlled trial

BACKGROUND

Carnitine deficiency is common in patients on hemodialysis. However, the efficacy of L-carnitine supplementation for improving lean body mass (LBM) and physical function has not yet been evaluated.

METHODS

In this multicenter, prospective, parallel, randomized, controlled trial, 91 patients on hemodialysis who developed carnitine deficiency were randomly assigned to receive injections of 1,000 mg L-carnitine 3 times per week after each hemodialysis session (L-carnitine group) or no injections (control group) with monitoring for 12 months.

RESULTS

The data for 84 of the 91 patients were available for analysis (L-carnitine group, n = 42; control group, n = 42). Dry weight and body mass index did not significantly change in the L-carnitine group, but significantly decreased in the control group. Arm muscle area (AMA) did not change significantly in the L-carnitine group but decreased significantly in the control group; the difference in mean AMA between the groups was 6.22% (95% confidence interval [CI] 1.90-10.5; P = 0.037). Hand grip strength did not change significantly in the L-carnitine group, but decreased significantly in the control group. The difference in change in hand grip strength between the groups was 4.27% (95% CI 0.42-8.12; P = 0.030). Furthermore, LBM did not change significantly in the L-carnitine group but decreased significantly in the control group; the difference in mean LBM between the groups was 2.92 % (95% CI 1.28-4.61; P = 0.0007).

CONCLUSIONS

L-carnitine supplementation is useful in patients who develop carnitine deficiency on hemodialysis because it maintains physical function and LBM.

Effects of levocarnitine on cardiac function, urinary albumin, hs-CRP, BNP, and troponin in patients with coronary heart disease and heart failure

OBJECTIVE

To investigate the effects of levocarnitine on cardiac function, urinary albumin (ALB), high-sensitivity C-reactive protein (hs-CRP), brain natriuretic peptide (BNP), and troponin in patients with coronary heart disease (CHD) and heart failure (HF).

METHODS

In total, 246 patients with CHD-caused HF were selected and randomly divided into Group A and Group B. A fully automatic biochemical analyzer was used to measure the levels of ALB, hs-CRP, BNP, and troponin in both groups of patients, and the expression levels of LVDD and LVEF were detected by cardiac color ultrasonography. Patients in Group B were intravenously injected with 3.0 g of levocarnitine, once per day. After 14 days, changes in levels of ALB, hs-CRP, BNP, troponin, LVDD, and LVEF in Group A patients were detected.

RESULTS

The effective cure rates of patients in both groups were 65.8% and 81.3%, respectively, and there was a statistically significant difference between the two groups (p < 0.05). After administration of levocarnitine, all indicators showed decreasing trends, but the LVEF level increased. Among them, patients treated with levocarnitine showed the most evident decrease in LVEF. Decrease in BNP was the largest (p < 0.05). Additionally, there was no statistical difference in incidence rate between the two groups (5.8% vs. 2.5%, p = 0.222).

CONCLUSION

Levocarnitine can effectively improve ALB, hs-CRP, BNP, troponin, and LVDD levels to improve cardiac function rating and thus improve cardiac function.

Association between 4-year all-cause mortality and carnitine profile in maintenance hemodialysis patients

Background

Patients on dialysis are in a chronic carnitine-deficient state. This condition may be associated with abnormalities of the fatty acid and organic acid metabolisms. Carnitine is required for β-oxidation of the long-chain fatty acids; therefore, carnitine deficiency decreases the efficiency of ATP synthesis and may incur death. However, the details of this association remain unknown. We examined the relationship between β-oxidation efficiency represented by the carnitine profile and 4-year all-cause mortality in hemodialysis patients.

Methods

The carnitine profiles of 122 hemodialysis patients were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The associations between the 4-year all-cause mortality and carnitine profile as well as the clinical backgrounds of the patients were investigated. A survival analysis was conducted by the Kaplan–Meier survival method and multivariable Cox proportional hazard analysis. The bootstrap method was performed to confirm the stability and robustness of our model.

Results

Of the 122 subjects analyzed, 111 were selected and 24 died during the observation period. Stepwise multivariable Cox regression demonstrated that diabetes state [Hazard ratio (95% confidence interval), 4.981 (2.107–11.77)], age [HR (95% CI), 1.052 (1.014–1.091)], and the acetylcarnitine/(palmitoylcarnitine+octadecenoylcarnitine) [C2/(C16+C18:1)] ratio [HR (95% CI), 0.937 (0.904–0.971)] were independent significant factors of 4-year all-cause mortality. The bootstrap method confirmed the significance of these three factors.

Conclusion

The 4-year all-cause mortality negatively correlated with the C2/(C16+C18:1) ratio. Improvement of the impaired β-oxidation state after L-carnitine administration may ameliorate prognosis.

Role of carnitine and its derivatives in the development and management of type 2 diabetes

Type 2 diabetes is a highly prevalent chronic metabolic disorder characterized by hyperglycemia and associated with several complications such as retinopathy, hyperlipidemia and polyneuropathy. The dysregulated fatty acid metabolism along with tissue lipid accumulation is generally assumed to be associated in the development of insulin resistance and T2D. Moreover, several studies suggest a central role for oxidative stress in the pathogenesis of the disease. Since L-carnitine (LC) has an indispensable role in lipid metabolism via its involvement in the β-oxidation of long-chain fatty acids and it has antioxidant properties as well, carnitine supplementation may prove to be an effective tool in the management of the clinical course of T2D. In this review we summarize the results from animal and clinical studies demonstrating the effects of supplementation with LC or LC derivatives (acetyl-LC, propionyl-LC) on various metabolic and clinical parameters associated with T2D.

"Biocompatible" Neutral pH Low-GDP Peritoneal Dialysis Solutions: Much Ado About Nothing?

Adverse outcomes in peritoneal dialysis (PD), including PD related infections, the loss of residual kidney function (RKF), and longitudinal, deleterious changes in peritoneal membrane function continue to limit the long-term success of PD therapy. The observation that these deleterious changes occur upon exposure to conventional glucose-based PD solutions fuels the search for a more biocompatible PD solution. The development of a novel PD solution with a neutral pH, and lower in glucose degradation products (GDPs) compared to its conventional predecessors has been labeled a "biocompatible" solution. While considerable evidence in support of these novel solutions' biocompatibility has emerged from cell culture and animal studies, the clinical benefits as compared to conventional PD solutions are less clear. Neutral pH low GDP (NpHLGDP) PD solutions appear to be effective in reducing infusion pain, but their effects on other clinical endpoints including peritoneal membrane function, preservation of RKF, PD-related infections, and technique and patient survival are less clear. The literature is limited by studies characterized by relatively few patients, short follow-up time, heterogeneity with regards to the novel PD solution type under study, and the different patient populations under study. Nonetheless, the search for a more biocompatible PD solution continues with emerging data on promising non glucose-based solutions.

Levocarnitine Improves Cardiac Function in Hemodialysis Patients With Left Ventricular Hypertrophy: A Randomized Controlled Trial

BACKGROUND

Levocarnitine deficiency in hemodialysis patients is common. Although the effect of levocarnitine therapy on uremic anemia has been studied in small trials, its effects on cardiac function remain unclear.

STUDY DESIGN

Multicenter, prospective, open-label, parallel, randomized, controlled trial.

SETTING & PARTICIPANTS

Patients undergoing maintenance hemodialysis with carnitine deficiency (free carnitine plasma concentration < 40μmol/L) enrolled in 3 hemodialysis centers.

INTERVENTION

Random assignment to treatment for 12 months with oral levocarnitine therapy at a dose of 20mg/kg/d or control group (no levocarnitine therapy).

OUTCOMES & MEASUREMENTS

Cardiac function was assessed by echocardiography. The primary end point was change in ejection fraction from baseline at the end of the study. Secondary end points included changes in left ventricular mass index and clinical parameters from baseline at the end of the study.

RESULTS

222 patients were randomly assigned, of whom 148 patients (levocarnitine group, n=75; control group, n=73) were analyzed. Ejection fraction increased from baseline to the end of the study in the levocarnitine group by 5.43% (95% CI, 4.53%-6.32%), but not in the control group (change, -0.14%; between-group difference, 5.57% [95% CI, 4.48%-6.66%]; P<0.001). Left ventricular mass index decreased from baseline to the end of the study in the levocarnitine group (change of -8.89 [95% CI, -11.7 to -6.09] g/m(2)), but not in the control group (change of 1.62g/m(2); between-group difference, 10.50 [95% CI, 7.51 to 13.60] g/m(2); P<0.001). Levocarnitine therapy reduced N-terminal pro-brain natriuretic peptide (NT-proBNP) levels and improved the erythropoietin responsiveness index, whereas no such effects were observed in the control group.

LIMITATIONS

Not a double-blinded study.

CONCLUSIONS

Levocarnitine therapy is useful for hemodialysis patients with carnitine deficiency; these patients may benefit from such therapy, with amelioration of cardiac function and reduction of left ventricular mass index.

Effects of levocarnitine on brachial-ankle pulse wave velocity in hemodialysis patients: a randomized controlled trial

Background and Aims: Atherosclerotic cardiovascular disease is the most common cause of mortality in patients with end-stage kidney disease. Chronic kidney disease patients often exhibit a deficiency in l-carnitine due to loss during hemodialysis (HD). We studied the effects of l-carnitine supplementation on brachial-ankle pulse wave velocity (baPWV), a marker of atherosclerosis, in HD patients. Methods: This was a prospective, open-label, randomized, parallel controlled, multi-center trial testing the anti-atherosclerotic efficacy of oral l-carnitine administration (20 mg/kg/day). HD patients (n = 176, mean age, 67.2 ± 10.3 years old; mean duration of HD, 54 ± 51 months) with plasma free l-carnitine deficiency (<40 μmol/L) were randomly assigned to the oral l-carnitine group (n = 88) or control group (n = 88) and monitored during 12 months of treatment. Results: There were no significant differences in baseline clinical variables between the l-carnitine and control groups. l-carnitine supplementation for 12 months significantly increased total, free, and acyl carnitine levels, and reduced the acyl/free carnitine ratio. The baPWV value decreased from 2085 ± 478 cm/s at baseline to 1972 ± 440 cm/s after six months (p < 0.05) to 1933 ± 363 cm/s after 12 months (p < 0.001) of l-carnitine administration, while no significant changes in baPWV were observed in the control group. Baseline baPWV was the only factor significantly correlated with the decrease in baPWV. Conclusions: l-carnitine supplementation significantly reduced baPWV in HD patients. l-carnitine may be a novel therapeutic strategy for preventing the progression of atherosclerotic cardiovascular disease.

Effects of switching from oral administration to intravenous injection of l-carnitine on lipid metabolism in hemodialysis patients

Background

Carnitine deficiency may contribute to cardiovascular disease (CVD) in patients with hemodialysis (HD). Dyslipidemia plays a role in CVD and its prevalence is also high in HD patients. We examined here the effects of switching from oral administration (PO) to intravenous (IV) injection of l-carnitine on lipid metabolism in patients with HD.

Methods

Nine HD patients who had received l-carnitine orally (900 mg/day) for 1 year were enrolled in this study. We examined whether lipid parameters were improved by switching to IV injection therapy of 1000 mg l-carnitine.

Results

IV injection of l-carnitine for 1 week significantly increased total, free and acyl carnitine levels both before and after HD. Switching to IV injection therapy for 1 and 4 weeks decreased serum free fatty acid (FFA) (322 ± 104 versus 261 ± 124 µmol/L) and increased high-density lipoprotein-cholesterol levels (1.46 ± 0.49 versus 1.63 ± 0.62 mmol/L), respectively. Change in FFA values from the baseline (ΔFFA) was positively correlated with the Δacyl/free carnitine ratio (r² = 0.553, P = 0.022).

Conclusion

This study demonstrated that switching to IV l-carnitine therapy from oral supplementation improved lipid profiles, thus supporting the clinical utility of IV administration of l-carnitine for the treatment of patients on HD.

The effects of oral L-carnitine supplementation on physical capacity and lipid metabolism in chronic hemodialysis patients

Background

It is well known that the physical activity in chronic hemodialysis patients decreases compared to that in normal subjects. In order to investigate the effects of L-carnitine on physical capacity and lipid metabolism, a cardiopulmonary exercise test using a bicycle ergometer was performed before and after 3 months of oral L-carnitine supplementation under double-blind conditions.

Methods and Results

A total of 20 stable outpatients undergoing hemodialysis treatment were randomly divided into 2 groups: controls receiving placebo and patients receiving 900 mg L-carnitine p.o. daily. The levels of free and acyl carnitine increased significantly from 22.9 ± 7.3 to 149.9 ± 51.8 μmol/l and from 16.0 ± 2.8 to 100.3 ± 50.2 μmol/l, respectively, in the L-carnitine group; however, there was no significant change in other plasma lipid profiles. The exercise time was decreased and the heart rate at the anaerobic threshold was increased in the control group 3 months after the study period, but there were no such changes observed in the L-carnitine group. The minute ventilation/CO₂ output slope increased significantly from 38.9 ± 7.8 to 43.8 ± 11.8 in the L-carnitine group. It has been speculated that a shift in the energy source occurs from carbohydrate to lipid, in terms of an increase of oxygen demand.

Conclusion

L-Carnitine supplementation might have some beneficial effects on the physical capacity of chronic hemodialysis patients due to the improvement of the lipid metabolism in the muscle.

Hemodynamic stabilizing effects of L-carnitine in chronic hemodialysis patients

BACKGROUND

The effects of L-carnitine on the hemodynamic state of chronic hemodialysis patients have been debated. In order to clarify the effect of administered L-carnitine on cardiac function and hypotensive episodes during the hemodialysis procedure, a randomized double-blind placebo-controlled study was performed for 3 months.

METHODS AND RESULTS

TWENTY STABLE OUTPATIENTS UNDERGOING HEMODIALYSIS TREATMENT WERE DIVIDED INTO TWO GROUPS: controls (placebo) and treated patients (L-carnitine 900 mg p.o. daily). After 3 months, cardiac function was reevaluated by echocardiography, and hypotensive episodes during hemodialysis were assessed. Free and acyl carnitine levels increased significantly from 22.3 ± 7.1 to 140.3 ± 57.5 μmol/l and from 15.8 ± 2.8 to 94.8 ± 50.4 μmol/l, respectively, in the treated group. The ejection fraction significantly increased from 61.8 ± 16.0 to 64.4 ± 13.8% (p < 0.05) in the treated group. However, there was no difference in other echocardiographic parameters between the two groups. Hypotensive episodes significantly decreased from 4.0 ± 1.7 to 1.3 ± 0.9 times per month (p < 0.05), although patients' body weight did not change significantly.

CONCLUSIONS

Beneficial effects of L-carnitine on the hemodynamic state of chronic hemodialysis patients were observed. L-Carnitine supplementation might be considered especially for chronic hemodialysis patients with unstable hemodynamic conditions.

Carnitine supplementation improves cardiac strain rate in children on chronic hemodialysis

BACKGROUND

Carnitine plays a key role in energy production in the myocardium. Carnitine deficiency commonly occurs in patients on chronic hemodialysis (HD) and may contribute to cardiomyopathy.

METHODS

Carnitine levels and cardiac function of nine children on HD were assessed before and after 6 months of intravenous levocarnitine supplementation. Standard echocardiographic (ECHO) measures of left ventricular (LV) function as well as strain and strain rate analysis using novel speckle-tracking echocardiography were performed and the results compared to those of a control group of children on chronic HD.

RESULTS

Following carnitine supplementation, total (49.0 ± 1.67 vs. 298.0 ± 31.8 μmol/L) and free carnitine (29.0 ± 1.20 vs. 180.4 ± 19.2 μmol/L) increased (p < 0.0001), and the acyl:free (A:F) carnitine ratio improved (0.73 ± 0.04 vs. 0.65 ± 0.05; p = 0.02). There were no changes in standard ECHO measures of LV function, including end diastolic dimension, mass index, ejection fraction, and fractional shortening. There was significant (p = 0.017) improvement in the longitudinal strain rate (-1.48 ± 0.11 vs -1.91 ± 0.12) after carnitine supplementation in the study group. No improvements in LV function, strain, or strain rate occurred in controls.

CONCLUSIONS

Levocarnitine supplementation improved carnitine levels, the A:F ratio, and longitudinal strain rate in children on HD.

L-carnitine supplementation and EPO requirement in children on chronic hemodialysis

L-carnitine supplementation has been the subject of heated discussion in the context of the treatment of pediatric hemodialysis patients. The aim of this study was to analyze the effect of intravenous L-carnitine supplementation on the erythropoetin (EPO) requirement in six pediatric hemodialysis patients. All patients were on intravenous L-carnitine (2.5 g per session for patients >30 kg and 1 g for those <30 kg) for 9 months. The EPO dose was adapted monthly to maintain a target hemoglobin (Hb) level of 11-13 g/dl. Prior to the initiation of L-carnitine supplementation, the EPO requirement was 1.15 +/- 0.22 (range 0.37-1.75) microg/kg darbepoetin alpha. Free carnitine (FC) levels were measured before (40.4 +/- 4.9 micromol/l), immediately after the 9-month L-carnitine supplementation period (378.5 +/- 77.3 micromol/l), and 4 months after withdrawal of L-carnitine (95.6 +/- 4.0 micromol/l). After 9 months, the EPO dose was 0.47 +/- 0.10 microg/kg (p < 0.002). The Hb levels increased from 12.2 +/- 0.97 to 14.0 +/- 0.54 g/dl (p < 0.05) within the first 2 months, and the EPO dose was then decreased in a stepwise manner. In conclusion, following intravenous carnitine supplementation, FC levels were higher and persisted longer than expected. This rise was associated with increased Hb levels and decreased EPO requirement. Since controls were missing for this study, prospective long-term multi-center studies on a large number of patients are required to provide solid answers to the controversial question of L-carnitine supplementation in hemodialyzed children.

Challenges of nutrition intervention for malnourished dialysis patients

Malnutrition, or protein energy wasting (PEW), is prevalent in patients with chronic kidney disease stage 5 dialysis (CKD-5). One criterion of PEW strongly associated with morbidity and mortality in CKD-5 dialysis patients is the serum albumin level. Serum albumin levels have not improved over the past 10 years. Typical intervention strategies need to be reevaluated. Intradialytic parenteral nutrition (IDPN) is a form of parenteral nutrition delivered during dialysis that is a convenient and assured route of nutrition alimentation for high-nutrition-risk PEW patients who cannot improve nutrition status by oral and enteral routes. Recent qualification criteria for IDPN changes in Medicare part D have made this therapy an available option for many more of these high-nutrition-risk PEW patients. Nutrition support knowledge in clinicians is essential to administer IDPN effectively and to optimize clinical response. An improved understanding of the milieu of uremia and PEW of CKD-5, as well as the study of nutrition interventions inclusive of IDPN, will allow for effective strategies toward improved outcomes in the future.

Fatigue in patients receiving maintenance dialysis: a review of definitions, measures, and contributing factors

Fatigue is a debilitating symptom or side effect experienced by many patients on long-term dialysis therapy. Fatigue has a considerable effect on patient health-related quality of life and is viewed as being more important than survival by some patients. Renal providers face many challenges when attempting to reduce fatigue in dialysis patients. The lack of a reliable, valid, and sensitive fatigue scale complicates the accurate identification of this symptom. Symptoms of daytime sleepiness and depression overlap with fatigue, making it difficult to target specific therapies. Moreover, many chronic health conditions common in the long-term dialysis population may lead to the development of fatigue and contribute to the day-to-day and diurnal variation in fatigue in patients. Key to improving the assessment and treatment of fatigue is improving our understanding of potential mediators, as well as potential therapies. Cytokines have emerged as an important mediator of fatigue and have been studied extensively in patients with cancer-related fatigue. In addition, although erythropoietin-stimulating agents have been shown to mitigate fatigue, the recent controversy regarding erythropoietin-stimulating agent dosing in patients with chronic kidney disease suggests that erythropoietin-stimulating agent therapy may not serve as the sole therapy to improve fatigue in this population. In conclusion, fatigue is an important and often underrecognized symptom in the dialysis population. Possible interventions for minimizing fatigue in patients on long-term dialysis therapy should aim at improving health care provider awareness, developing improved methods of measurement, understanding the pathogenesis better, and managing known contributing factors.

Protective effect of intravenous levocarnitine on subsequent-month hospitalization among prevalent hemodialysis patients, 1998 to 2003

BACKGROUND

Levocarnitine deficiency in hemodialysis patients is common. Although the effect of intravenous levocarnitine therapy was studied in small trials, the effect on global outcomes in larger populations is unclear.

STUDY DESIGN

Retrospective observational study.

SETTING & PARTICIPANTS

Centers for Medicare & Medicaid Services data; prevalent hemodialysis patients, 1998 to 2003.

PREDICTOR

Intravenous levocarnitine use, clinical characteristics, comorbid conditions.

OUTCOMES & MEASUREMENTS

Effect of 1 g or greater per dialysis session of levocarnitine for 10 or more sessions during a month on subsequent hospitalization days. Repeated-measures and marginal structural models were fit, the latter to account for time-dependent confounding.

RESULTS

Of the study population, 3% to 7% received levocarnitine for 1 month per year or more. Treated patients were older with more severe comorbidity and larger erythropoietin doses than untreated patients. In repeated-measures model analysis adjusted for demographic characteristics and disease severity, 1 g or greater per dialysis session of levocarnitine for 10 or more sessions during a month was associated with a 10.8% (95% confidence interval, 9.7 to 11.9; P < 0.01) subsequent-month decrease in hospitalization days. In marginal structural model analysis, levocarnitine therapy was associated with a 21.7% (95% confidence interval, 18.4 to 24.9; P < 0.01) decrease in hospitalization days.

LIMITATIONS

Algorithm for identifying comorbid conditions from claims validated only for diabetes; biochemical marker levels unavailable in Medicare claims; levocarnitine therapy quantified only while patients were not hospitalized.

CONCLUSION

Because hemodialysis patients are hospitalized about 15 days yearly, the association of monthly levocarnitine regimen with lower hospitalization rate is clinically significant. The causality of this association must be confirmed by randomized clinical trials.

Advances in Carnitine in Chronic Uremia

Carnitine is a conditionally essential metabolite that plays a critical role in cell physiology. Carnitine is necessary for fatty acid transport to sites of beta-oxidation in the mitochondria, where it helps to prevent organic acid accumulation. Because of these key regulatory functions, carnitine represents a crucial determinant of mitochondrial energy metabolism, whose deficiency may lead to metabolic and clinical disturbances. Loss of carnitine through dialytic membranes occurs in maintenance hemodialysis, resulting in potential carnitine depletion and relative increments of esterified carnitine forms. Carnitine supplementation has been shown to counteract such alterations and may be associated with clinical benefit. In particular, carnitine supplementation in patients on hemodialysis may enhance response to erythropoietin, resulting in improved hematologic status. Carnitine was also reported to improve exercise tolerance and intradialytic symptoms. Carnitine supplementation may enhance insulin resistance, inflammatory and antioxidant status, protein balance, lipid profile, and cardiac function. Carnitine administration can be useful for selected patients on dialysis who do not adequately respond to standard therapy.