A randomized, double-blind, placebo-controlled trial of supplementary vitamins E, C and their combination for treatment of haemodialysis cramps

Pharmacological Treatment for Dialysis-Related Muscle Cramps: A Systematic Review

BACKGROUND

Patients with end-stage renal disease undergoing dialysis suffer from muscle cramps, a prevalent and burdensome symptom for which there is a paucity of efficient and safe treatments.

AIM

What is the efficacy and safety of pharmacological interventions for the treatment of dialysis-related muscle cramps?

DESIGN

A systematic review was conducted in OVID, CINAHL, PubMed, Web of Science, and Central Cochrane databases up to August 25, 2023.

DATA SOURCES

Experimental studies reporting on a pharmacological intervention for the treatment of dialysis-related muscle cramps were included. The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis, and the studies quality was assessed with the RoB2 tool.

RESULTS

A total of 4660 studies were retrieved, and 13 articles were included. The studies reported on nine interventions: vitamin C, vitamin E, vitamin K2, vitamin B7, dextrose solutions, gabapentin, sodium chloride, creatine monohydrate, and L-carnitine. The studies testing L-carnitine and creatine monohydrate were the only ones deemed to have a low risk of bias. Side effects were reported in only two trials, consisting primarily of gastrointestinal discomfort and hyperglycemia. Vitamins C and E are the two most studied interventions that showed positive results in reducing the frequency, severity, and duration of dialysis-related muscle cramps. L-carnitine is a promising intervention that warrants further investigation.

CONCLUSION

Our review consolidates the existing evidence, elucidating the range of treatments along with their potential benefits and limitations. Future studies should uphold high-quality standards, incorporate patient-reported outcomes, and utilize well-defined, robust samples to improve patient care.

Antioxidants for adults with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a significant risk factor for cardiovascular disease (CVD) and death. Increased oxidative stress in people with CKD has been implicated as a potential causative factor. Antioxidant therapy decreases oxidative stress and may consequently reduce cardiovascular morbidity and death in people with CKD. This is an update of a Cochrane review first published in 2012.

OBJECTIVES

To examine the benefits and harms of antioxidant therapy on death and cardiovascular and kidney endpoints in adults with CKD stages 3 to 5, patients undergoing dialysis, and kidney transplant recipients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies until 15 November 2022 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

We included all randomised controlled trials investigating the use of antioxidants, compared with placebo, usual or standard care, no treatment, or other antioxidants, for adults with CKD on cardiovascular and kidney endpoints.

DATA COLLECTION AND ANALYSIS

Titles and abstracts were screened independently by two authors who also performed data extraction using standardised forms. Results were pooled using random effects models and expressed as risk ratios (RR) or mean difference (MD) with 95% confidence intervals (CI). Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included 95 studies (10,468 randomised patients) that evaluated antioxidant therapy in adults with non-dialysis-dependent CKD (31 studies, 5342 patients), dialysis-dependent CKD (41 studies, 3444 patients) and kidney transplant recipients (21 studies, 1529 patients). Two studies enrolled dialysis and non-dialysis patients (153 patients). Twenty-one studies assessed the effects of vitamin antioxidants, and 74 assessed the effects of non-vitamin antioxidants. Overall, the quality of included studies was moderate to low or very low due to unclear or high risk of bias for randomisation, allocation concealment, blinding, and loss to follow-up. Compared with placebo, usual care, or no treatment, antioxidant therapy may have little or no effect on cardiovascular death (8 studies, 3813 patients: RR 0.94, 95% CI 0.64 to 1.40; I² = 33%; low certainty of evidence) and probably has little to no effect on death (any cause) (45 studies, 7530 patients: RR 0.95, 95% CI 0.82 to 1.11; I² = 0%; moderate certainty of evidence), CVD (16 studies, 4768 patients: RR 0.79, 95% CI 0.63 to 0.99; I² = 23%; moderate certainty of evidence), or loss of kidney transplant (graft loss) (11 studies, 1053 patients: RR 0.88, 95% CI 0.67 to 1.17; I² = 0%; moderate certainty of evidence). Compared with placebo, usual care, or no treatment, antioxidants had little to no effect on the slope of urinary albumin/creatinine ratio (change in UACR) (7 studies, 1286 patients: MD -0.04 mg/mmol, 95% CI -0.55 to 0.47; I² = 37%; very low certainty of evidence) but the evidence is very uncertain. Antioxidants probably reduced the progression to kidney failure (10 studies, 3201 patients: RR 0.65, 95% CI 0.41 to 1.02; I² = 41%; moderate certainty of evidence), may improve the slope of estimated glomerular filtration rate (change in eGFR) (28 studies, 4128 patients: MD 3.65 mL/min/1.73 m², 95% CI 2.81 to 4.50; I² = 99%; low certainty of evidence), but had uncertain effects on the slope of serum creatinine (change in SCr) (16 studies, 3180 patients: MD -13.35 µmol/L, 95% CI -23.49 to -3.23; I² = 98%; very low certainty of evidence). Possible safety concerns are an observed increase in the risk of infection (14 studies, 3697 patients: RR 1.30, 95% CI 1.14 to 1.50; I² = 3%; moderate certainty of evidence) and heart failure (6 studies, 3733 patients: RR 1.40, 95% CI 1.11 to 1.75; I² = 0; moderate certainty of evidence) among antioxidant users. Results of studies with a low risk of bias or longer follow-ups generally were comparable to the main analyses.

AUTHORS' CONCLUSIONS

We found no evidence that antioxidants reduced death or improved kidney transplant outcomes or proteinuria in patients with CKD. Antioxidants likely reduce cardiovascular events and progression to kidney failure and may improve kidney function. Possible concerns are an increased risk of infections and heart failure among antioxidant users. However, most studies were of suboptimal quality and had limited follow-up, and few included people undergoing dialysis or kidney transplant recipients. Furthermore, the large heterogeneity in interventions hampers drawing conclusions on the efficacy and safety of individual agents.

KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for nutrition in kidney diseases since 1999. Since the publication of the first KDOQI nutrition guideline, there has been a great accumulation of new evidence regarding the management of nutritional aspects of kidney disease and sophistication in the guidelines process. The 2020 update to the KDOQI Clinical Practice Guideline for Nutrition in CKD was developed as a joint effort with the Academy of Nutrition and Dietetics (Academy). It provides comprehensive up-to-date information on the understanding and care of patients with chronic kidney disease (CKD), especially in terms of their metabolic and nutritional milieu for the practicing clinician and allied health care workers. The guideline was expanded to include not only patients with end-stage kidney disease or advanced CKD, but also patients with stages 1-5 CKD who are not receiving dialysis and patients with a functional kidney transplant. The updated guideline statements focus on 6 primary areas: nutritional assessment, medical nutrition therapy (MNT), dietary protein and energy intake, nutritional supplementation, micronutrients, and electrolytes. The guidelines primarily cover dietary management rather than all possible nutritional interventions. The evidence data and guideline statements were evaluated using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

Treatment of nocturnal leg cramps by blockade of the medial branch of the deep peroneal nerve after lumbar spine surgery

INTRODUCTION

Patients with lumbar spine disease sometimes complain of nocturnal leg cramps. We sought to investigate the effectiveness of blocking the medial branch of the deep peroneal nerve as treatment for nocturnal leg cramps after spinal surgery for lumbar spine disease.

METHODS

We evaluated 66 postoperative patients in this prospective comparative study of a group of patients with a nerve block (n = 41) and a control group without (n = 25). In the block group, the medial branch of the deep peroneal nerve was blocked at the distal two-thirds of the interspace between the first and second metatarsals using 5.0 mL of 1.0% lidocaine.

RESULTS

Two weeks after the block, the frequency of nocturnal leg cramps was reduced to less than a quarter of pretreatment baseline frequency in 61.0% of patients (n = 25) and less than half in 80.5% (n = 33). In the control group, the frequency of the leg cramps was reduced from baseline in 32.0% of patients (n = 8), and was unchanged or increased in 68.0% (n = 17) at 2 weeks. Cramp frequency was reduced to less than a quarter or less than half of baseline frequency in a significantly (P < 0.05 and P < 0.01, respectively) larger percentage of patients in the block group. The severity of each cramp was less in about two-thirds of patients (63.4%; n = 26) in the block group and was unchanged in one-third (31.7%; n = 13).

CONCLUSIONS

Blocking the medial branch of the peroneal nerve can be an effective, long-lasting, and simple treatment with low risk for nocturnal cramps sustained after lumbar spine surgery.

An Approach to Pain Management in End Stage Renal Disease: Considerations for General Management and Intradialytic Symptoms

The prevalence and severity of symptoms in patients with advanced chronic kidney disease is higher than those of the general population and comparable to those with other chronic and serious medical conditions. Despite the prevalence and severity in this population, symptoms continue to be under-recognized and inadequately managed. The recognition of specific intradialytic pain syndromes such as pain related to arteriovenous access, headaches, muscle cramps or generalized pain by providers may aid in improving patient compliance and quality of life. The approach to pain management in end stage renal disease patients follows that of the general population with specific considerations regarding clearance and potential side effects guiding selection of agents. Overall, evidence is limited regarding the pharmacology of many medications in this population.

Quinine for muscle cramps

BACKGROUND

Muscle cramps can occur anywhere and for many reasons. Quinine has been used to treat cramps of all causes. However, controversy continues about its efficacy and safety. This review was first published in 2010 and searches were updated in 2014.

OBJECTIVES

To assess the efficacy and safety of quinine-based agents in treating muscle cramps.

SEARCH METHODS

On 27 October 2014 we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL, MEDLINE and EMBASE. We searched reference lists of articles up to 2014. We also searched for ongoing trials in November 2014.

SELECTION CRITERIA

Randomised controlled trials of people of all ages with muscle cramps in any location and of any cause, treated with quinine or its derivatives.

DATA COLLECTION AND ANALYSIS

Three review authors independently selected trials for inclusion, assessed risk of bias and extracted data. We contacted study authors for additional information. For comparisons including more than one trial, we assessed the quality of the evidence using Grading of Recommendations Assessment, Development and Evaluation (GRADE).

MAIN RESULTS

We identified 23 trials with a total of 1586 participants. Fifty-eight per cent of these participants were from five unpublished studies. Quinine was compared to placebo (20 trials, n = 1140), vitamin E (four trials, n = 543), a quinine-vitamin E combination (three trials, n = 510), a quinine-theophylline combination (one trial, n = 77), and xylocaine injections into the gastrocnemius muscle (one trial, n = 24). The most commonly used quinine dosage was 300 mg/day (range 200 to 500 mg). We found no new trials for inclusion when searches were updated in 2014.The risk of bias in the trials varied considerably. All 23 trials claimed to be randomised, but only a minority described randomisation and allocation concealment adequately.Compared to placebo, quinine significantly reduced cramp number over two weeks by 28%, cramp intensity by 10%, and cramp days by 20%. Cramp duration was not significantly affected.A significantly greater number of people suffered minor adverse events on quinine than placebo (risk difference (RD) 3%, 95% confidence interval (CI) 0% to 6%), mainly gastrointestinal symptoms. Overdoses of quinine have been reported elsewhere to cause potentially fatal adverse effects, but in the included trials there was no significant difference in major adverse events compared with placebo (RD 0%, 95% CI -1% to 2%). One participant suffered from thrombocytopenia (0.12% risk) on quinine.A quinine-vitamin E combination, vitamin E alone, and xylocaine injections into gastrocnemius were not significantly different to quinine across all outcomes, including adverse effects. Based on a single trial comparison, quinine alone was significantly less effective than a quinine-theophylline combination but with no significant differences in adverse events.

AUTHORS' CONCLUSIONS

There is low quality evidence that quinine (200 mg to 500 mg daily) significantly reduces cramp number and cramp days and moderate quality evidence that quinine reduces cramp intensity. There is moderate quality evidence that with use up to 60 days, the incidence of serious adverse events is not significantly greater than for placebo in the identified trials, but because serious adverse events can be rarely fatal, in some countries prescription of quinine is severely restricted.Evidence from single trials suggests that theophylline combined with quinine improves cramps more than quinine alone, and the effects of xylocaine injections into gastrocnemius are not significantly different to quinine across all outcomes. Low or moderate quality evidence shows no significant difference between quinine and vitamin E or quinine and quinine-vitamin E mixture. Further research into these alternatives, as well other pharmacological and non-pharmacological treatments, is thus warranted.There is no evidence to judge optimal dosage or duration of quinine treatment. Further studies using different dosages and measurement of serum quinine levels will allow a therapeutic range to be defined for muscle cramp. Because serious adverse events are not common, large population studies are required to more accurately inform incidence. Longer lengths of follow-up in future trials will help determine the duration of action following cessation of quinine as well as long-term adverse events. The search for new therapies, pharmacological and nonpharmacological, should continue and further trials should compare vitamin E, quinine-vitamin E combination, and quinine-theophylline mixture with quinine.

Efficacy of a massage roller combined with cooling lotion in the prevention of calf muscle cramps

In dieser offenen Anwendungsbeobachtung wurde an 208 Patienten über 4 Wochen geprüft, ob die Kombination des Massagerollers mit der Waden Massage Pflegelotion die Anzahl der Waden- und Fußkrämpfe senken kann. Zur Prophylaxe wurden täglich über mindestens 5 Minuten die betroffenen Muskeln ausgehend von der Großzehe in Rich-tung der Leiste mit dem Massageroller mit mäßig bis mittelstarkem Druck ausgerollt. Bei 151 Patienten zeigte sich eine deutliche Besserung, indem die Frequenz der Wadenkrämpfe um mehr als die Hälfte abnahm bzw. keine Wadenkrämpfe mehr auftraten. Auch die Krampflänge nahm durch Anwendung des Massagerollers bei einem aktuellen Wadenkrampf ab. Die Häufigkeit und Stärke wurde in einem Fragebogen dokumentiert. Schwangere, jüngere Patienten, solche mit Venenerkrankungen und Männer in jedem sowie Frauen im mittleren Alter profitierten von der Anwendung des Massagerollers am besten.

Comparison of vitamin e and L-carnitine, separately or in combination in patients with intradialytic complications

BACKGROUND

The most common complications during dialysis are hypotension and muscle cramps. There are many strategies to prevent and treat these complications.

OBJECTIVES

The aim of this study is to evaluate effects of vitamin E and L-carnitine supplementation alone and in combination on intradialytic complications.

PATIENTS AND METHODS

In a prospective study, 20 patients with end stage renal disease on chronic hemodialysis that had intradialytic complications such as hypotension, muscle cramp, nausea, vomiting and headache were studied. These patients were studied in four 45 day periods, beginning with no treatment (step 1), receiving vitamin E (200 IU/d) (step 2), receiving L-carnitine (500 mg/d) (step 3) and their combination (step 4). Intradialytic complications were recorded in each step and compared between treatments.

RESULTS

All three treatments significantly reduced frequency of muscle cramps in comparison to baseline values. Vitamin E alone and in combination with L-carnitine reduced the frequency of muscle cramps more effectively. Hypotension was significantly lower in combination therapy in comparison to baseline values and vitamin E treatment.

CONCLUSIONS

Vitamin E and L-carnitine both have comparative effects on intradialytic complications. As the combination use of vitamin E and L-carnitine could more effectively reduce the intradialytic complications, it is recommended for daily use in hemodialysis patients.

Water-soluble vitamins in people with low glomerular filtration rate or on dialysis: a review

People with low glomerular filtration rate and people on dialysis are spontaneously at risk for vitamin deficiency because of the potential for problems with decreased appetite and decreased sense of smell and taste, leading to decreased intake, and because decreased energy or decreased cognitive ability results in difficulties in shopping and cooking. Imposed dietary restrictions because of their renal dysfunction and because of comorbidities such as hypertension and diabetes exacerbate this problem. Finally, particularly for water-soluble vitamins, loss may occur into the dialysate. We did not identify any randomized trials of administering daily doses close to the recommended daily allowances of these vitamins. In people who are eating at all, deficiencies of B5 and B7 seem unlikely. It is unclear whether supplements of B2 and B3 are necessary. Because of dialyzability and documented evidence of insufficiency in dialysis patients, B1 supplementation is likely to be helpful. B6, B9, and B12 are implicated in the hyperhomocysteinemia observed in patients on dialysis. These vitamins have been studied in combinations, in high doses, with the hope of reducing cardiovascular outcomes. No reductions in patient-important outcomes were seen in adequately powered randomized trials. Because of their involvement in the homocysteine pathway, however, supplementation with lower doses, close to the recommended daily allowances, may be helpful. Vitamin C deficiency is common in patients on dialysis who are not taking supplements: low-dose supplements are warranted. Vitamins for dialysis patients contain most or all of the B vitamins and low-dose vitamin C. We are not aware of any medical reasons to choose one over another.

Treatment for cramps in amyotrophic lateral sclerosis/motor neuron disease

BACKGROUND

Cramps are painful, involuntary muscle contractions. They commonly affect people with amyotrophic lateral sclerosis/motor neuron disease (ALS/MND) at all stages of the disease. To date, the treatment of muscle cramps in ALS has been largely empirical without any evidence from randomised controlled trials.

OBJECTIVES

To systematically assess the effect of interventions on muscle cramps as a primary or secondary endpoint or adverse event in people with ALS/MND.

SEARCH METHODS

We searched the Cochrane Neuromuscular Disease Group Specialized Register (14 February 2011), the Cochrane Central Register of Controlled Trials (Issue 1, 2011 in The Cochrane Library), MEDLINE (January 1966 to January 2011) and EMBASE (January 1980 to January 2011) and reference lists of articles searched using the terms motor neuron disease, motor neurone disease, motoneuron disease or amyotrophic lateral sclerosis. We contacted authors of trials for further information.

SELECTION CRITERIA

We included all randomised and quasi-randomised trials of oral medications in people with ALS which assessed cramps as a primary or secondary outcome measure or as an adverse event. We also included trials using subcutaneous or intravenous medications or physical therapy.

DATA COLLECTION AND ANALYSIS

All authors applied the selection criteria and assessed study quality independently, and all authors performed independent data extraction.

MAIN RESULTS

Twenty studies including 4789 participants were identified. Only one trial, of tetrahydrocannabinol (THC), assessed cramps as the primary endpoint. Thirteen studies assessed cramps as a secondary endpoint. The medications comprised vitamin E, baclofen, riluzole, L-threonine, xaliproden, indinavir, and memantine. Six studies assessed cramps as an adverse event. The medications comprised creatine, gabapentin, dextromethorphan, quinidine, and lithium. In all 20 studies no favourable effect for the treatment of cramps in ALS/MND could be demonstrated, but many studies were underpowered to draw a definite conclusion. A meta-analysis of two small studies showed a statistically nonsignificant result for the amino acid L-threonine for the treatment of cramps in ALS/MND. No study was identified using physical therapy as a therapeutic intervention for cramps.

AUTHORS' CONCLUSIONS

There is no evidence to support the use of any intervention for muscle cramps in ALS/MND. More and larger randomised controlled trials evaluating treatments for muscle cramps in ALS/MND are needed.

Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases

BACKGROUND

Our systematic review has demonstrated that antioxidant supplements may increase mortality. We have now updated this review.

OBJECTIVES

To assess the beneficial and harmful effects of antioxidant supplements for prevention of mortality in adults.

SEARCH METHODS

We searched The Cochrane Library, MEDLINE, EMBASE, LILACS, the Science Citation Index Expanded, and Conference Proceedings Citation Index-Science to February 2011. We scanned bibliographies of relevant publications and asked pharmaceutical companies for additional trials.

SELECTION CRITERIA

We included all primary and secondary prevention randomised clinical trials on antioxidant supplements (beta-carotene, vitamin A, vitamin C, vitamin E, and selenium) versus placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Three authors extracted data. Random-effects and fixed-effect model meta-analyses were conducted. Risk of bias was considered in order to minimise the risk of systematic errors. Trial sequential analyses were conducted to minimise the risk of random errors. Random-effects model meta-regression analyses were performed to assess sources of intertrial heterogeneity.

MAIN RESULTS

Seventy-eight randomised trials with 296,707 participants were included. Fifty-six trials including 244,056 participants had low risk of bias. Twenty-six trials included 215,900 healthy participants. Fifty-two trials included 80,807 participants with various diseases in a stable phase. The mean age was 63 years (range 18 to 103 years). The mean proportion of women was 46%. Of the 78 trials, 46 used the parallel-group design, 30 the factorial design, and 2 the cross-over design. All antioxidants were administered orally, either alone or in combination with vitamins, minerals, or other interventions. The duration of supplementation varied from 28 days to 12 years (mean duration 3 years; median duration 2 years). Overall, the antioxidant supplements had no significant effect on mortality in a random-effects model meta-analysis (21,484 dead/183,749 (11.7%) versus 11,479 dead/112,958 (10.2%); 78 trials, relative risk (RR) 1.02, 95% confidence interval (CI) 0.98 to 1.05) but significantly increased mortality in a fixed-effect model (RR 1.03, 95% CI 1.01 to 1.05). Heterogeneity was low with an I(2)- of 12%. In meta-regression analysis, the risk of bias and type of antioxidant supplement were the only significant predictors of intertrial heterogeneity. Meta-regression analysis did not find a significant difference in the estimated intervention effect in the primary prevention and the secondary prevention trials. In the 56 trials with a low risk of bias, the antioxidant supplements significantly increased mortality (18,833 dead/146,320 (12.9%) versus 10,320 dead/97,736 (10.6%); RR 1.04, 95% CI 1.01 to 1.07). This effect was confirmed by trial sequential analysis. Excluding factorial trials with potential confounding showed that 38 trials with low risk of bias demonstrated a significant increase in mortality (2822 dead/26,903 (10.5%) versus 2473 dead/26,052 (9.5%); RR 1.10, 95% CI 1.05 to 1.15). In trials with low risk of bias, beta-carotene (13,202 dead/96,003 (13.8%) versus 8556 dead/77,003 (11.1%); 26 trials, RR 1.05, 95% CI 1.01 to 1.09) and vitamin E (11,689 dead/97,523 (12.0%) versus 7561 dead/73,721 (10.3%); 46 trials, RR 1.03, 95% CI 1.00 to 1.05) significantly increased mortality, whereas vitamin A (3444 dead/24,596 (14.0%) versus 2249 dead/16,548 (13.6%); 12 trials, RR 1.07, 95% CI 0.97 to 1.18), vitamin C (3637 dead/36,659 (9.9%) versus 2717 dead/29,283 (9.3%); 29 trials, RR 1.02, 95% CI 0.98 to 1.07), and selenium (2670 dead/39,779 (6.7%) versus 1468 dead/22,961 (6.4%); 17 trials, RR 0.97, 95% CI 0.91 to 1.03) did not significantly affect mortality. In univariate meta-regression analysis, the dose of vitamin A was significantly associated with increased mortality (RR 1.0006, 95% CI 1.0002 to 1.001, P = 0.002).

AUTHORS' CONCLUSIONS

We found no evidence to support antioxidant supplements for primary or secondary prevention. Beta-carotene and vitamin E seem to increase mortality, and so may higher doses of vitamin A. Antioxidant supplements need to be considered as medicinal products and should undergo sufficient evaluation before marketing.

Amyotrophic lateral sclerosis: pathophysiology, diagnosis and management

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease associated with a life expectancy of approximately 3 years after symptom onset, but the range of survival extends from a few months for some to decades for approximately 5% of patients. There is no clear cause in the majority of cases and just one medication, riluzole, has been shown to modestly prolong survival. Research has identified some of the cellular processes that occur after disease onset, including mitochondrial dysfunction, protein aggregation, generation of free radicals, excitotoxicity, inflammation and apoptosis, but for most patients the underlying cause is unknown. While ALS is considered to be a complex genetic disorder in which multiple genes in combination with environmental exposures combine to render a person susceptible, few genetic or environmental risks have been discovered to date. The diagnosis is based on the history and examination showing progressive upper and lower motor neuron findings. The electromyogram can help confirm the diagnosis, and additional tests are used to exclude other conditions. Published practice parameters guide the care of patients with ALS. Until the elucidation of aetiologies leads to the development of more robust neuroprotective agents, both pharmacological and nonpharmacological treatments are directed at maintaining quality of life and prolonging life to the greatest extent possible. Riluzole, ventilatory support for those with respiratory insufficiency, gastrostomy for those with dysphagia and multidisciplinary care may help extend life. The off-label use of many symptomatic agents can have a meaningful impact for those with the illness. Palliative care ensures dignity toward the end stages of the disease. Clinical trials currently aim to slow disease progression by testing drugs that impact one or more of the processes that are initiated after disease onset. Novel therapies currently in trials include potential neuroprotective agents with differing mechanisms of action, vaccine therapies, stem cell injections and diaphragmatic pacing.

Quinine for muscle cramps

BACKGROUND

Muscle cramps can occur anywhere and for many reasons. Quinine has been used to treat cramps of all causes. However, controversy continues about its efficacy and safety.

OBJECTIVES

To assess the efficacy and safety of quinine in treating muscle cramps.

SEARCH STRATEGY

We searched The Cochrane Neuromuscular Disease Group Register, The Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 3, 2010), MEDLINE, EMBASE and reference lists of articles up to July 2010.

SELECTION CRITERIA

Randomised controlled trials of people of all ages with muscle cramps in any location and of any cause, treated with quinine or its derivatives.

DATA COLLECTION AND ANALYSIS

Three authors independently selected trials for inclusion, assessed risk of bias and extracted data. We contacted study authors for additional information.

MAIN RESULTS

We identified 23 trials with a total of 1586 participants. Fifty-eight per cent of these participants were from five unpublished studies. Quinine was compared to placebo (20 trials, n =1140), vitamin E (four trials, n = 543), a quinine-vitamin E combination (three trials, n = 510), a quinine-theophylline combination (one trial, n = 77), and xylocaine injections into the gastrocnemius muscle (one trial, n = 24). The most commonly used quinine dosage was 300 mg/day (range 200 to 500 mg).Compared to placebo, quinine significantly reduced cramp number over two weeks by 28%, cramp intensity by 10%, and cramp days by 20%. Cramp duration was not significantly affected.A significantly greater number of people suffered minor adverse events on quinine than placebo (risk difference +3%, 95% confidence intervals 0% to 6%), mainly gastrointestinal symptoms. Overdoses of quinine have been reported elsewhere to cause potentially fatal adverse effects, but in the included trials there was no significant difference in major adverse events compared with placebo (risk difference 0%, 95% confidence intervals -1% to 2%). One participant suffered from thrombocytopenia (0.12% risk) on quinine.A quinine-vitamin E combination, vitamin E alone, and xylocaine injections into gastrocnemius were not significantly different to quinine across all outcomes, including adverse effects. Based on a single trial comparison, quinine alone was significantly less effective than a quinine-theophylline combination but with no significant differences in adverse events.

AUTHORS' CONCLUSIONS

There is moderate quality evidence that quinine significantly reduces cramp frequency, intensity and cramp days in dosages between 200 and 500 mg/day. There is moderate quality evidence that with use up to 60 days, the incidence of serious adverse events is not significantly greater than for placebo in the identified trials. Further research is required on the optimal dose and duration of use, and also on alternative treatments.

Water-soluble vitamin levels in extended hours hemodialysis

Patients on extended hours (>15 h/week) hemodialysis may be at a higher risk of deficiency of water-soluble vitamins than conventional (≤15 h/week) hemodialysis patients due to their increased weekly hours of dialysis. We compared serum levels of the water-soluble vitamins in a group of extended and conventional hours hemodialysis patients. Predialysis serum levels of vitamin C, vitamin B12, thiamine, pyridoxine, and folate were measured in 52 patients: 26 extended group and 26 conventional group. Information on patient's intake of vitamin supplements and dialysis regimen was obtained. Data were log transformed due to the skewed distribution of the results. Median vitamin C levels were significantly lower in the extended group (0.30 vs. 1.14 mg/dL, P<0.001), with 7 patients having a level <0.18 mg/dL. Thiamine levels were also lower in the extended group (median 211 vs. 438.5 nmol/L, P=0.0005). However, extended patients had higher levels of pyridoxine (23.2 vs. 11.1 ng/mL, P=0.03). Vitamin B12 and folate levels were not significantly different between the groups. There was significant variability in vitamin supplement prescription in both groups, and dietary data were not obtained. This study showed a high incidence of vitamin C deficiency in extended hours hemodialysis patients, suggesting that supplementation is warranted. It also supports an ongoing role for multivitamin supplementation in conventional hemodialysis patients.

Parenteral ascorbic acid in haemodialysis patients

PURPOSE OF REVIEW

Parenteral ascorbic acid has been frequently used to overcome problems of vitamin C deficiency in haemodialysis patients. The benefits of vitamin C supplementation in clinical studies have been controversial and did not consider toxicological aspects. The review summarizes recent findings of the effects of parenteral ascorbic acid and discusses toxicological effects.

RECENT FINDINGS

Vitamin C deficiency in haemodialysis patients, which has been frequently described, cannot be improved with oral supplementation due to limited absorption of high dosages. To avoid consequences of vitamin C deficiency, parenteral vitamin C solutions should be administered because this intervention is the only way to guarantee a sufficient supply to the cells. A beneficial consequence of parenteral vitamin C on the recombinant human erythropoietin resistance is an additional therapeutic effect, which contributes to the prevention of iron deficiency anaemia in haemodialysis patients. Thus, large amount of supplemental vitamin C are required for extended periods of time (up to 500 mg 3 times a week). To avoid hyperoxaluria, plasma oxalate levels should be monitored on a regular basis, for example, once a week.

SUMMARY

Parenteral administration of ascorbic acid may be an approach that can overcome problems of vitamin C deficiency in haemodialysis patients - in particular problems of iron overload, erythropoetin resistance, and chronic inflammation.

Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases

BACKGROUND

Animal and physiological research as well as observational studies suggest that antioxidant supplements may improve survival.

OBJECTIVES

To assess the effect of antioxidant supplements on mortality in primary or secondary prevention randomised clinical trials.

SEARCH STRATEGY

We searched The Cochrane Library (Issue 3, 2005), MEDLINE (1966 to October 2005), EMBASE (1985 to October 2005), and the Science Citation Index Expanded (1945 to October 2005). We scanned bibliographies of relevant publications and wrote to pharmaceutical companies for additional trials.

SELECTION CRITERIA

We included all primary and secondary prevention randomised clinical trials on antioxidant supplements (beta-carotene, vitamin A, vitamin C, vitamin E, and selenium) versus placebo or no intervention. Included participants were either healthy (primary prevention trials) or had any disease (secondary prevention trials).

DATA COLLECTION AND ANALYSIS

Three authors extracted data. Trials with adequate randomisation, blinding, and follow-up were classified as having a low risk of bias. Random-effects and fixed-effect meta-analyses were performed. Random-effects meta-regression analyses were performed to assess sources of intertrial heterogeneity.

MAIN RESULTS

Sixty-seven randomised trials with 232,550 participants were included. Forty-seven trials including 180,938 participants had low risk of bias. Twenty-one trials included 164,439 healthy participants. Forty-six trials included 68111 participants with various diseases (gastrointestinal, cardiovascular, neurological, ocular, dermatological, rheumatoid, renal, endocrinological, or unspecified). Overall, the antioxidant supplements had no significant effect on mortality in a random-effects meta-analysis (relative risk [RR] 1.02, 95% confidence interval [CI] 0.99 to 1.06), but significantly increased mortality in a fixed-effect model (RR 1.04, 95% CI 1.02 to 1.06). In meta-regression analysis, the risk of bias and type of antioxidant supplement were the only significant predictors of intertrial heterogeneity. In the trials with a low risk of bias, the antioxidant supplements significantly increased mortality (RR 1.05, 95% CI 1.02 to 1.08). When the different antioxidants were assessed separately, analyses including trials with a low risk of bias and excluding selenium trials found significantly increased mortality by vitamin A (RR 1.16, 95% CI 1.10 to 1.24), beta-carotene (RR 1.07, 95% CI 1.02 to 1.11), and vitamin E (RR 1.04, 95% CI 1.01 to 1.07), but no significant detrimental effect of vitamin C (RR 1.06, 95% CI 0.94 to 1.20). Low-bias risk trials on selenium found no significant effect on mortality (RR 0.91, 95% CI 0.76 to 1.09).

AUTHORS' CONCLUSIONS

We found no evidence to support antioxidant supplements for primary or secondary prevention. Vitamin A, beta-carotene, and vitamin E may increase mortality. Future randomised trials could evaluate the potential effects of vitamin C and selenium for primary and secondary prevention. Such trials should be closely monitored for potential harmful effects. Antioxidant supplements need to be considered medicinal products and should undergo sufficient evaluation before marketing.

Quinine-A Tonic Too Bitter for Hemodialysis-Associated Muscle Cramps?

Hemodialysis patients are susceptible to muscle cramps, both during dialysis sessions as well as in the interdialytic interval. These cramps are often very painful, disruptive to the dialysis treatment, and adversely affect quality of life. There is no well-defined means of preventing or treating these cramps. Quinine sulfate has been used with apparent success in some patients, but the Food and Drug Administration recently ordered the cessation of marketing of unapproved quinine formulations and advised consumers to avoid "off-label" use of quinine for cramps. We review the causes and consequences of hemodialysis-associated cramps, and discuss possible preventive measures and treatments.

Vitamin C neglect in hemodialysis: sailing between Scylla and Charybdis

In our efforts to meet the vitamin C requirements of dialysis patients we confront a medical dilemma--do we allow the patient to become depleted of vitamin C, with the accompanying hematological and other consequences (Scylla), or do we provide for adequate tissue levels of vitamin C, which has been thought to carry the risk of oxalosis (Charybdis). Many practitioners are certain that either one outcome (deficiency) or the other (oxalic acid toxicity) is inevitable, and much like Odysseus, no safe course is to be found. The recent accumulating evidence that vitamin C improves the management of anemia in dialysis patients compels us to find a safe passage through this dilemma. The serious vitamin C deficiency seen in many patients may also contribute to poor oral health and chronic fatigue. The evidence for oxalosis from vitamin C supplements stems from hemodialysis as practiced 20 years ago. Investigators using this therapy are not observing systemic oxalosis, and the most current data support the conclusion that vitamin C therapy is safe for dialysis patients. The question will be resolved by controlled trials that address both vitamin C effectiveness and safety.

Vitamin E in renal therapeutic regiments

Administration of vitamin E in children with immunoglobulin A (IgA) nephropathy, focal segmental glomerulosclerosis (FSGS) and type I diabetes demonstrated potential towards ameliorating progression. Oral vitamin E therapy reduced endothelial dysfunction, lipid peroxidation and oxidative stress in patients with chronic kidney failure (CKF). Moreover, the use of vitamin E-bonded hemodialyzers reduced atherosclerotic changes, erythropoietin dosage and muscular cramps in patients on hemodialysis (HD). However, several controlled clinical trials failed to document beneficial effects on the study subjects' cardiovascular and renal outcomes. A recent report of increased all-cause mortality in adult patients receiving high dose vitamin E therapy has caused considerable concern and debate. These issues regarding the efficacy and safety of vitamin E in renal therapeutic regimens will be reviewed in this article.

Musculoskeletal manifestations of chronic renal failure

Musculoskeletal problems remain among the main limitations of the quality of life of renal failure patients, in particular of those treated with long-term maintenance dialysis. Renal osteodystrophy continues to receive great attention. The mechanisms of uremic skeletal resistance to parathormone (PTH) are further investigated. The assay used for the dosage of "intact PTH" has been found to detect 7-84 fragments with an inhibitory effect on the action of the whole hormone. A decrease in the density of PTH receptor on osteoblasts is another recently evidenced factor. Investigations of the recently described RANK-RANKL system have demonstrated an increase in serum osteprotegerin levels, which, together with the two above-mentioned abnormalities, may explain bone resistance to PTH. These are important advances in the understanding of renal osteodystrophy as skeletal resistance to PTH appears to play an important part in the pathophysiology of secondary hyperparathyroidism and of adynamic bone disease. Because of this skeletal resistance, it has been recommended for several years that serum PTH level be monitored and kept twofold to threefold above the upper value of the normal level to maintain normal bone turnover in dialysis patients. Relative hypoparathyroidism has recently been found to be associated with increased spontaneous fracture rate and mortality, so this recommendation appears to hold adequate, despite the demonstration that serum PTH levels in this range are a poor predictor of bone turnover and that chronic parathyroid gland hyperplasia is likely to favor parathyroid gland autonomization. Recent publications have insisted on the role that hyperphosphatemia plays not only in the development of secondary hyperparathyroidism, but also of vascular, especially coronary, calcification and as a predictor of mortality. This "silent killer" of uremic patients is one of the main targets for therapeutic intervention. Extensive use of calcium-containing phosphate binders has been recently criticized as calcium overload appears to favor vascular calcification. Sevelaner (RenaGel) is a calcium- and aluminum-free phosphate binder that is an important advance in the management of renal osteodystrophy, especially in patients with extraskeletal calcification and hypercalcemia. The use of vitamin D derivatives has also raised concern because they enhance calcium and phosphorus absorption and reduce bone turnover. New metabolites with fewer hypercalcemic effects have been developed. Calcium-sensing receptor agonists are stimulating interest and are likely to take an important place in the future management of renal osteodystrophy. Uremic myopathy has received recent attention. Impaired muscle capillary oxygen transfer has been identified as a pathophysiologic factor, and progressive resistance training has been shown to improve the condition. Finally, a new entity, nephrogenic fibrosing dermopathy, has been described, which must be distinguished from calciphylaxis and scleromyxedema.