Improvement of anemia with erythropoietin and intravenous iron reduces sleep-related breathing disorders and improves daytime sleepiness in anemic patients with congestive heart failure

The treatment of chronic anemia in heart failure: a global approach

Chronic anemia is an independent risk factor for mortality in patients with heart failure (HF). Restoring physiological hemoglobin (Hb) levels is essential to increase oxygen transport capacity to tissues and improve cell metabolism as well as physical and cardiac performance. Nutritional deficits and iron deficiency are the major causes of chronic anemia, but other etiologies include chronic kidney disease, inflammatory processes, and unexplained anemia. Hormonal therapy, including erythropoietin (EPO) and anabolic treatment in chronic anemia HF patients, may contribute to improving Hb levels and clinical outcomes. Although preliminary studies showed a beneficial effect of EPO therapy on cardiac efficiency and in HF, more recent studies have not confirmed this positive impact of EPO, alluding to its side effect profile. Physical exercise significantly increases Hb levels and the response of anemia to treatment. In malnourished patients and chronic inflammatory processes, low levels of anabolic hormones, such as testosterone and insulin-like growth factor-1, contribute to the development of chronic anemia. This paper aims to review the effect of nutrition, EPO, anabolic hormones, standard HF treatments, and exercise as regulatory mechanisms of chronic anemia and their cardiovascular consequences in patients with HF.

Anemia in pregnancy and sleep of 6-month-old infants: A prospective cohort study

Objective

Anemia has been reported to adversely influence sleep in infants. However, the association between anemia in pregnancy and infant sleep remains unclear. We aimed to examine the association between maternal anemia in pregnancy and sleep parameters of 6-month-old infants.

Methods

We enrolled 2,410 mother-infant pairs between 2018 and 2021 in Hefei. Data on maternal hemoglobin concentration were collected at 24–28 gestational weeks from the electronic medical records of the hospitals. Nocturnal and daytime sleep duration, number of night awakenings, nocturnal wakefulness, and sleep latency of infants aged 6 months were measured using the Brief Infant Sleep Questionnaire with five items. A restricted cubic spline model was used to examine the relationship between maternal hemoglobin concentration and infant nocturnal sleep duration after adjusting for potential confounders.

Results

In our study, 807 (33.5%) mothers had anemia during pregnancy. Compared to infants born to mothers without anemia, infants born to mothers with anemia in pregnancy had shorter nocturnal sleep duration [mean (SD), 560.29 (79.57) mins vs. 574.27 (75.36) mins] at the age of 6 months. Subgroup analysis showed consistent significant differences in nocturnal sleep duration between infant born to anemic and non-anemic mothers, except in case of stratification by preterm birth [mean difference (mins), 2.03 (95% CI, −20.01, −24.07)] and pre-pregnancy obesity [mean difference (mins), −0.85 (95% CI, −16.86, −15.16)]. A J-shaped nonlinear correlation curve was observed between maternal hemoglobin concentration and infant nocturnal sleep duration. Compared with mothers without daily iron supplementation, mothers who had daily iron supplementation had higher hemoglobin concentrations [mean (SD), 112.39 (11.33) g/L vs. 110.66 (10.65) g/L] at delivery and their infants had longer nocturnal sleep duration [mean (SD), 565.99 (82.46) mins vs. 553.66 (76.03) mins].

Conclusion

Anemia in pregnancy may have an adverse influence on the sleep of 6-mon-old infants, and the relationship between maternal hemoglobin concentration and nocturnal sleep duration is nonlinear.

Dual Role of Fibroblast Growth Factor Pathways in Sleep Regulation

Sleep plays an important function in neuro-immuno-endocrine homeostasis. Sleep disorders have been associated with an increased risk of metabolic and cognitive impairments. Among different factors that have an effect on sleep metabolism, a growing body of literature has investigated growth factors in the course of sleep quality and disorders. A good example of growth factors is fibroblast growth factors (FGFs), which are a large family of polypeptide growth factors. Evidence has shown that FGFs are involved in the modulation of sleep-wake behavior by their receptor subtypes and ligands, e.g., FFG1 plays an important role in the quality of sleep through somnogenic effects, while the high level of FGF23 is associated with secondary disorders in shift workers. Therefore, a controversial effect of FGFs can be seen in the course of sleep in physiologic and pathologic conditions. Further investigation on this topic would help us to understand the role of FGFs in sleep disorders as a therapeutic option and biomarker.

Intravenous iron therapy improves the hypercapnic ventilatory response and sleep disordered breathing in chronic heart failure

AIMS

Intravenous iron therapy can improve symptoms in patients with heart failure, anaemia and iron deficiency. The mechanisms underlying such an improvement might involve chemoreflex sensing and nocturnal breathing patterns.

METHODS AND RESULTS

Patients with heart failure, reduced left ventricular ejection fraction, anaemia (haemoglobin <13 g/dl in men; <12 g/dl in women) and iron deficiency (ferritin <100 or 100-299 μg/L with transferrin saturation <20%) were 2:1 randomized to patient-tailored intravenous ferric carboxymaltose dose or placebo. Chemoreflex sensitivity cardiorespiratory sleep study, symptom assessment and cardiopulmonary exercise test were performed before and 2 weeks after the last treatment dose. Fifty-eight patients (38 active arm/20 placebo arm) completed the study. Intravenous iron was associated with less severe symptoms, higher haemoglobin (12.5 ± 1.4 vs. 11.7 ± 1.0 mg/dl, p < 0.05) and improved haematinic parameters. Ferric carboxymaltose improved the central hypercapnic ventilatory response (-25.8%, p < 0.05 vs. placebo), without changes in peripheral chemosensitivity. In particular, the central hypercapnic ventilatory responses passed from 4.6 ± 6.5 to 2.9 ± 2.9 L/min/mmHg after ferric carboxymaltose and from 4.4 ± 4.6 to 4.6 ± 3.9 L/min/mmHg after placebo (p_{treatment*condition}  = 0.046). In patients presenting with sleep-related breathing disorder, apnoea-hypopnoea index was reduced with active treatment as compared to placebo (12 ± 11 vs. 19 ± 13 events/h, p < 0.05). After ferric carboxymaltose, but not after placebo, both peak oxygen uptake (VO₂ ) increased (Δ1.1 ± 2.0 ml/kg/min, p < 0.05) and VO₂ /workload slope was steeper (Δ0.67 ± 1.7 L/min/W, p < 0.01).

CONCLUSIONS

Intravenous ferric carboxymaltose improves the hypercapnic ventilatory response and sleep-related breathing disorders in patients with heart failure, anaemia and iron deficiency. These newly described findings, along with improved oxygen delivery to exercising muscles, likely contribute to the favourable effects of ferric carboxymaltose in anaemic patients with heart failure.

Associations between anemia and insomnia or excessive daytime sleepiness in older adults

OBJECTIVE

Sleep disorders including excessive daytime sleepiness (EDS), insomnia and anemia are both common. The aim of this study is to investigate associations between anemia and insomnia/EDS in the elderly.

METHODS

A total of 744 older outpatients were included in this cross-sectional study. Anemia was defined as a hemoglobin concentration below 12 g/dL in females and <13 g/dl in males. Patients were divided into two groups as anemic and non-anemic. The Epworth Sleepiness Scale score of ≥11 points indicates EDS. Insomnia Severity Index with scores of ≥8 indicates insomnia.

RESULTS

The mean age was 79.8±7.7 years. The prevalence of insomnia, EDS and anemia was 62.1%, 23.8%, and 47.2%, respectively. Insomnia (66.3% vs 58.5%) and EDS (29.6% vs 18.6%) were more common in patients with anemia compared to those without anemia (p<0.05). In univariate analysis, there were significant associations between anemia and insomnia [odds ratio (OR):1.4, 95% confidence interval (CI):1.0-1.9], and EDS (OR:1.8,95% CI:1.3-2.6). In multivariate analysis, the relationship between insomnia and nocturia, chronic obstructive pulmonary disease (COPD), and number of drugs used persisted, whereas being male, of an older age, coronary arterial disease, COPD, Parkinson's disease, dementia, and urinary incontinence were associated with EDS (p<0.05), but there was no significant relationships between anemia and insomnia/EDS (p>0.05).

CONCLUSION

The present data suggests that an elderly who has anemia is 1.4 times more likely to experience insomnia and 1.8 times more likely to experience EDS than those without anemia.

Sleep-disordered breathing and comorbidities: role of the upper airway and craniofacial skeleton

Obstructive sleep-disordered breathing (SDB), which includes primary snoring through to obstructive sleep apnea syndrome (OSAS), may cause compromise of respiratory gas exchange during sleep, related to transient upper airway narrowing disrupting ventilation, and causing oxyhemoglobin desaturation and poor sleep quality. SDB is common in chronic disorders and has significant implications for health. With prevalence rates globally increasing, this condition is causing a substantial burden on health care costs. Certain populations, including people with sickle cell disease (SCD), exhibit a greater prevalence of OSAS. A review of the literature provides the available normal polysomnography and oximetry data for reference and documents the structural upper airway differences between those with and without OSAS, as well as between ethnicities and disease states. There may be differences in craniofacial development due to atypical growth trajectories or extramedullary hematopoiesis in anemias such as SCD. Studies involving MRI of the upper airway illustrated that OSAS populations tend to have a greater amount of lymphoid tissue, smaller airways, and smaller lower facial skeletons from measurements of the mandible and linear mental spine to clivus. Understanding the potential relationship between these anatomical landmarks and OSAS could help to stratify treatments, guiding choice towards those which most effectively resolve the obstruction. OSAS is relatively common in SCD populations, with hypoxia as a key manifestation, and sequelae including increased risk of stroke. Combatting any structural defects with appropriate interventions could reduce hypoxic exposure and consequently reduce the risk of comorbidities in those with SDB, warranting early treatment interventions.

[Central sleep apnea in patients with chronic heart failure]

Cheyne-Stokes respiration (CSR) is a form of sleep-disordered breathing seen in approximately half of patients with chronic heart failure and low left ventricular ejection fraction. The authors describe clinical features of CSR, mortality rate, treatment variants. Effects of continuous positive airway pressure (CPAP), bi-level ventilation, adaptive servoventilation (ASV) in patients with CSR and chronic heart failure are discussed. Diuretic acetazolamide is one more therapeutic option for CSR. It improves central sleep apnea and related daytime symptoms in patients with heart failure.

Sleep disordered breathing and fibroblast growth factor 23 in the Hispanic Community Health Study/Study of Latinos

Preclinical data suggest that hypoxia stimulates fibroblast growth factor 23 (FGF23) transcription and cleavage in osteocytes, resulting in elevated circulating c-terminal (cFGF23) levels but normal intact FGF23 (iFGF23) levels. We conducted a case-control study within the Hispanic Community Health Study/Study of Latinos to investigate whether sleep disordered breathing, as a model of hypoxemia, is independently associated with elevated cFGF23 levels in the general population and with elevated cFGF23 and iFGF23 levels in patients with chronic kidney disease (CKD), in whom FGF23 cleavage may be impaired. Cases (n = 602) had severe sleep disordered breathing defined as an apnea/hypopnea index (AHI) of ≥30. Controls without severe sleep disordered breathing (n = 602) were matched for sex and CKD stage. The median AHI in the cases was 45.8 (IQR 35.5-62.5) compared to 2.6 (IQR 0.6-8.2) in the controls. Cases had higher cFGF23 levels than controls (66.2 RU/mL, IQR 52.8-98.4 vs. 61.2 RU/mL, IQR 49.5-80.1, p value <0.001). There were no differences in iFGF23 levels between cases and controls. In adjusted linear regression and multinomial regression analyses, body mass index attenuated the relationship between severe sleep disordered breathing and cFGF23 levels. No significant relationships were seen in analyses of severe sleep disordered breathing and iFGF23 levels or in analyses of iFGF23 and cFGF23 stratified by CKD status. Additional studies using other models of intermittent and chronic hypoxia are needed to confirm whether hypoxia stimulates FGF23 transcription in humans and to determine the impact on iFGF23 levels in CKD.

Sleep apnoea in heart failure: To treat or not to treat?

Heart failure (HF) and sleep apnoea are common disorders which frequently coexist. Two main types of apnoea occur: one is obstructive which, through recurring episodes of snoring, hypoxaemia, large negative intra-thoracic pressures and arousals from sleep leading to downstream inflammatory and autonomic nervous system changes, is thought to be a causative factor to the development of systemic hypertension and HF. The other type of apnoea, Cheyne-Stokes respiration with central sleep apnoea (CSR-CSA), is characterized by an oscillatory pattern of ventilation with a prevailing hyperventilation-induced hypocapnia, often in the absence of significant hypoxaemia and snoring, and is thought to be a consequence of advanced HF-related low cardiac output, high sympathetic nervous system activation and pulmonary congestion. CSR-CSA may be a compensatory response to advanced HF. Rostral fluid shift during sleep may play an important role in the pathogenesis of both obstructive sleep apnoea (OSA) and CSA. Studies of positive airway pressure (PAP) treatment of OSA and CSA in HF have shown short-term improvements in cardiac and autonomic function; however, there is no evidence of improved survival. Loop gain may provide useful marker of continuous PAP (CPAP) responsiveness in patients with central apnoea. A greater understanding of the pathophysiology of the interaction between obstructive and central apnoea and the various types of HF, and the mechanisms of therapies, such as PAP, is required to develop new strategies to overcome the disabling symptoms, and perhaps improve the mortality, that accompany HF with sleep apnoea.

Principles of practice parameters for the treatment of sleep disordered breathing in the elderly and frail elderly: the consensus of the International Geriatric Sleep Medicine Task Force

Sleep disordered breathing (SDB) is a leading cause of morbidity worldwide. Its prevalence increases with age. Due to the demographic changes in industrial societies, pulmonologists and sleep physicians are confronted with a rapidly growing number of elderly SDB patients. For many physicians, it remains unclear how current guidelines for SDB management apply to elderly and frail elderly patients. The goal of this consensus statement is to provide guidance based on published evidence for SDB treatment in this specific patient group.

Clinicians and researchers with expertise in geriatric sleep medicine representing several countries were invited to participate in a task force. A literature search of PubMed from the past 12 years and a systematic review of evidence of studies deemed relevant was performed.

Recommendations for treatment management of elderly and frail elderly SDB patients based on published evidence were formulatedviadiscussion and consensus.

In the last 12 years, there have been surprisingly few studies examining treatment of SDB in older adults and even fewer in frail older adults. Studies that have been conducted on the management of SDB in the older patient population were rarely stratified for age. Studies in SDB treatment that did include age stratification mainly focused on middle-aged and younger patient groups. Based on the evidence that is available, this consensus statement highlights the treatment forms that can be recommended for elderly SDB patients and encourages treatment of SDB in this large patient group.

Adaptive servo-ventilation therapy improves long-term prognosis in heart failure patients with anemia and sleep-disordered breathing

Sleep disordered breathing (SDB) and anemia influences the progression of chronic heart failure (CHF). Adaptive servo-ventilation (ASV) is an effective therapeutic device for treatment of CHF, however, the impacts of ASV on CHF patients with or without anemia remain unclear.A total of 139 patients with CHF and SDB were divided into two groups: those treated with ASV (n = 53) and without ASV (n = 86). All patients were prospectively followed after discharge with the endpoints of cardiac death or progressive heart failure requiring rehospitalization. There were 65 patients (47%) with anemia among all subjects. The apnea hypopnea index was improved, and plasma BNP and high sensitive C-reactive protein levels were decreased in both groups with and without anemia by ASV therapy. The Kaplan-Meier survival curve demonstrated that the cardiac event-free rate in patients with ASV was significantly higher than in those without ASV in the anemia group (P = 0.008). However, in the non-anemia group, the cardiac event-free rate was similarly high in patients both with and without ASV (P = 0.664). Multivariate Cox proportional hazard analysis demonstrated that ASV use was an independent predictor of cardiac events in the anemia group (P = 0.0308), but not in the non-anemia group.ASV treatment for CHF and SDB has more favorable impacts in patients with anemia than in those without anemia.

Anemia in heart failure patients

Heart failure is a very common disease, with severe morbidity and mortality, and a frequent reason of hospitalization. Anemia and a concurrent renal impairment are two major risk factors contributing to the severity of the outcome and consist of the cardio renal anemia syndrome. Anemia in heart failure is complex and multifactorial. Hemodilution, absolute or functional iron deficiency, activation of the inflammatory cascade, and impaired erythropoietin production and activity are some pathophysiological mechanisms involved in anemia of the heart failure. Furthermore other concomitant causes of anemia, such as myelodysplastic syndrome and chemotherapy, may worsen the outcome. Based on the pathophysiology of cardiac anemia, there are several therapeutic options that may improve hemoglobin levels, tissues' oxygenation, and probably the outcome. These include administration of iron, erythropoiesis-stimulating agents, and blood transfusions but still the evidence provided for their use remains limited.

The treatment of central sleep apnea syndromes in adults: practice parameters with an evidence-based literature review and meta-analyses

The International Classification of Sleep Disorders, Second Edition (ICSD-2) distinguishes 5 subtypes of central sleep apnea syndromes (CSAS) in adults. Review of the literature suggests that there are two basic mechanisms that trigger central respiratory events: (1) post-hyperventilation central apnea, which may be triggered by a variety of clinical conditions, and (2) central apnea secondary to hypoventilation, which has been described with opioid use. The preponderance of evidence on the treatment of CSAS supports the use of continuous positive airway pressure (CPAP). Much of the evidence comes from investigations on CSAS related to congestive heart failure (CHF), but other subtypes of CSAS appear to respond to CPAP as well. Limited evidence is available to support alternative therapies in CSAS subtypes. The recommendations for treatment of CSAS are summarized as follows: CPAP therapy targeted to normalize the apnea-hypopnea index (AHI) is indicated for the initial treatment of CSAS related to CHF. (STANDARD)Nocturnal oxygen therapy is indicated for the treatment of CSAS related to CHF. (STANDARD)Adaptive Servo-Ventilation (ASV) targeted to normalize the apnea-hypopnea index (AHI) is indicated for the treatment of CSAS related to CHF. (STANDARD)BPAP therapy in a spontaneous timed (ST) mode targeted to normalize the apnea-hypopnea index (AHI) may be considered for the treatment of CSAS related to CHF only if there is no response to adequate trials of CPAP, ASV, and oxygen therapies. (OPTION)The following therapies have limited supporting evidence but may be considered for the treatment of CSAS related to CHF after optimization of standard medical therapy, if PAP therapy is not tolerated, and if accompanied by close clinical follow-up: acetazolamide and theophylline. (OPTION)Positive airway pressure therapy may be considered for the treatment of primary CSAS. (OPTION)Acetazolamide has limited supporting evidence but may be considered for the treatment of primary CSAS. (OPTION)The use of zolpidem and triazolam may be considered for the treatment of primary CSAS only if the patient does not have underlying risk factors for respiratory depression. (OPTION)The following possible treatment options for CSAS related to end-stage renal disease may be considered: CPAP, supplemental oxygen, bicarbonate buffer use during dialysis, and nocturnal dialysis. (OPTION) .

Managing anemia in patients with chronic heart failure: what do we know?

Anemia is common in patients with chronic heart failure (HF) with an incidence ranging from 4% to 55% depending on the studied population. Several studies have highlighted that the prevalence of anemia increases with worsening heart failure as reflected by New York Heart Association classification. Additionally, several epidemiological studies have highlighted its role as a prognostic marker, linking it to worse outcomes including; malnutrition, increased hospitalizations, refractory heart failure and death. The pathophysiology of anemia is multifactorial and related to various factors including; hemodilution, iron losses from anti-platelet drugs, activation of the inflammatory cascade, urinary losses of erythropoietin and associated renal insufficiency. There are a host of epidemiological studies examining HF outcomes and anemia, but only a few randomized trials addressing this issue. The purpose of this article is to review the literature that examines the interrelationship of anemia and congestive HF, analyzing its etiology, impact on outcomes and also the role of associated kidney disease as well as cardiorenal syndrome both as a marker of morbidity and mortality.

Erythropoiesis-stimulating agents for anaemia in chronic heart failure patients

BACKGROUND

Chronic heart failure (CHF) is a leading cause of morbidity and mortality worldwide. Anaemia is a common (12-55%) co-morbid condition and is associated with worsening symptoms and increased mortality. Anaemia is treatable and can be targeted in the treatment of patients with CHF. Erythropoiesis-stimulating agents (ESA), supplemented by iron therapy, are used to treat anaemia in chronic kidney disease and cancer, however safety concerns have been raised in these patients. The clinical benefit and safety of these agents in CHF remains unclear.

OBJECTIVES

To assess the benefits and risks of ESA for CHF patients with anaemia.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library 2008, Issue 3), MEDLINE (1950 to October 2008), EMBASE (1980 to October 2008) and reference lists of articles. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials of any ESA, with or without iron therapy, in CHF patients were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Three reviewers independently assessed study quality and extracted data. Original authors were contacted for additional information. The outcomes of interest were: exercise tolerance, haemoglobin level, New York Heart Association (NYHA) functional class, quality of life, left-ventricular ejection fraction, B-type natriuretic peptide, CHF-related hospitalisations, all-cause mortality and adverse effects. Risk ratios (RR) were calculated for dichotomous data and weighted mean difference (WMD) for continuous data.

MAIN RESULTS

Eleven studies (794 participants) were included. Overall quality of studies was moderate with nine studies being placebo-controlled but only five double-blinded. Compared to control, ESA treatment significantly improved exercise duration by 96.8 seconds (95% CI 5.2 to 188.4, p=0.04) and 6-minute walk distance by 69.3 metres (95% CI 17.0 to 121.7, p=0.009). Benefit was also noted in terms of peak VO2 (+2.29 mL/kg/min, p=0.007), NYHA class (-0.73, p<0.001), ejection fraction (+5.8%, p<0.001), B-type natriuretic peptide (-226.99 pg/mL, p<0.001) and quality-of-life indicators, with a mean increase in haemoglobin of 1.98 g/dL (p<0.0001). There was also a significantly lower rate of heart failure related hospitalisations (RR 0.62, 95% CI 0.44 to 0.87) and lower all-cause mortality (RR 0.61, 95% CI 0.37 to 0.99). No increase in adverse events with ESA therapy was observed, however studies were of small sample sizes and limited duration.

AUTHORS' CONCLUSIONS

Meta-analysis of small RCTs suggests that ESA treatment in patients with symptomatic CHF and mild anaemia (haemoglobin more than 10g/dL) can improve anaemia and exercise tolerance, reduce symptoms and have benefits on clinical outcomes. Confirmation requires well-designed studies with careful attention to dose, haemoglobin treatment target and associated iron therapy.

Sleep-disordered breathing and heart failure: focus on obstructive sleep apnea and treatment with continuous positive airway pressure

BACKGROUND

Among patients with heart failure, sleep-disordered breathing is a common problem, with a prevalence ranging from 24% to 76%. Encompassed within the general category of sleep-disordered breathing are 2 types of sleep apnea: obstructive sleep apnea (OSA) occurs when the oropharyngeal musculature relaxes, causing a collapse of the upper airway, and central sleep apnea occurs when the brain stem fails to stimulate breathing.

METHODS AND RESULTS

This article focuses on the relationship between heart failure and OSA, the treatment of OSA with continuous positive airway pressure (CPAP), and the role of CPAP in improving such effects of heart failure as ejection fraction, blood pressure, sympathetic activity, sleepiness, heart rate, and mortality.

CONCLUSIONS

It is important to distinguish the type of sleep-disordered breathing a patient may have. Further studies are needed to elucidate the effects of CPAP and other therapies.

Iron deficiency and sleep disordered breathing in children--cause or effect?

OBJECTIVE

Iron deficiency is associated with paediatric sleep disturbances; in particular, restless leg syndrome (RLS) and periodic limb movement disorder (PLMD). Correction of iron deficiency has been shown to improve sleep disordered breathing (SDB) in certain adult populations. We evaluated the iron status of children diagnosed with SDB undergoing adenotonsillectomy.

METHODS

Consecutive children undergoing adenotonsillectomy for SDB between January 2007 and January 2008 were analysed. Routine blood tests were performed including full blood count and iron studies. Children were grouped according to age; 0-2 years (group A), 2-6 years (group B) and above 6 years (group C). Results were compared to local normal values and published data regarding normal values for paediatric populations.

RESULTS

94 children were included (60 male, 34 female). Mean age was 3.9 years (range 1.2-13.4 years). Iron deficiency was most marked in group A (n=8), with levels of ferritin (12.4), Mean Cell Haemoglobin (MCH) (25.0), iron saturation (16%, normal 20-40%) all below normal and Hb at the bottom of the normal range (11.0, normal 11-14.5). In group B (n=76), ferritin (19.4) and MCH (26.5) were again below normal but were higher than for group A. Average Hb for group B was 11.9.

CONCLUSION

The association between low iron and SDB in children has not previously been described. The results of this study highlighted low iron status in the children undergoing adenotonsillectomy for SDB. This was most severe in children under 6 years old. It is unclear whether low iron levels represent a cause or effect of SDB.

The role of correction of anaemia in patients with congestive heart failure: a short review

Many patients with Congestive Heart Failure (CHF) are anaemic. This anaemia is associated with more severe CHF and a higher incidence of mortality, hospitalisation and morbidity. The only way to prove that the anaemia is causing this worsening of CHF is to correct it. We review here some of the published papers about correction of anaemia. Many studies show a positive effect of Erythropoietin (EPO) or its' derivatives when administered in combination with oral or IV iron, with improvements in left and right ventricular systolic and diastolic function, dilation and hypertrophy and renal function. In addition, a reduction in hospitalisations, diuretic dose, pulmonary artery pressure, plasma volume, heart rate, serum Brain Natriuretic Peptide levels, the inflammatory marker Interleukin 6, soluble Fas ligand--a mediator of apoptosis, and improvements in New York Heart Association class, exercise capacity, oxygen utilization, caloric intake, Quality of Life and the activity of Endothelial Progenitor Cells, have been observed. Iron deficiency may also play an important role in this anaemia, since improvements in CHF have also been reported following treatment with IV iron alone. However, until the ongoing large placebo-controlled studies of the EPO derivative darbepoetin or IV iron are completed, we will not know whether these treatments really influence CHF outcome.