Capturing PLMS and their variability in children with sickle cell disease: does ankle activity monitoring measure up to polysomnography?

The Prevalence of Obstructive Sleep Apnea and Associated Symptoms among Patients with Sickle Cell Disease: A Systematic Review and Meta-analysis

Previous studies have shown that patients with sickle cell disease (SCD) are at high risk for obstructive sleep apnea (OSA). In the current study, we aimed to systematically review the literature to address the prevalence of OSA and associated symptoms among patients with SCD. Electronic databases, including Web of Science, Scopus, PubMed, Google Scholar, and Embase were systematically searched to identify the relevant original articles on patients with SCD. Newcastle Ottawa scale was used for quality assessment. Data were pooled by using random effects models. Subgroup analyses were performed by age groups. Thirty-nine studies containing details of 299,358 patients with SCD were included. The pooled results showed that more than half of these patients had OSA with different severities. The prevalence rates of OSA among children with apnea hypopnea index (AHI) cutoffs of above 1, 1.5, and 5 were 51% (95% confidence interval (CI) 36-67%), 29% (95% CI 19-40%), and 18% (95% CI 14-23%), respectively. The prevalence of OSA among adults with AHI cutoff of 5 was 43% (95% CI 21-64%). The pooled rates of snoring, nocturnal enuresis, nocturnal desaturation, and daytime sleepiness were 55% (95% CI 42-69%), 37% (95% CI 33-41%), 49% (95% CI 26-72%), and 21% (95% CI 12-30%), respectively. Given the high prevalence of OSA in patients with SCD, probable greater burden of SCD complications, and irreversible consequences of OSA, screening for OSA symptoms and signs seems useful in these patients. By screening and identifying this heterogeneous disorder earlier, available treatment modalities can be individualized for each patient.

The burden of sleep disordered breathing in children with sickle cell disease

Children with sickle cell disease (SCD) have an increased risk of sleep disordered breathing (SDB) compared with the general pediatric population. There has been a growing research interest on this field in recent years, yet many questions regarding risk factors and clinical implications of SDB remain unclear. The aim of this review is to provide a concise narrative and systematic synthesis of the available evidence on the epidemiology, clinical presentation, complications, and management, of SDB in children with SCD. An electronic search was conducted on studies published from the 1st of January 2000 to the 31st of December 2020 in PubMed/Medline, Scopus, and Cochrane databases. All studies focusing on SDB in children with SCD aged from 0 to 20 years were included. Studies were eligible for inclusion if available in the English language. A quantitative synthesis of the included studies was performed. Only studies focusing on specific treatment outcomes were included in a meta-analytic process. A total of 190 papers were initially identified. After screening the title and abstract, 112 articles were evaluated for eligibility. At the end of the selection process, 62 studies were included in the analysis. Sleep disordered breathing is associated with worse neurological, neurocognitive, and cardiological outcomes, whereas the association with frequency or severity of vaso-occlusive pain events and acute chest syndrome was not clarified. Therapeutic interventions like adenotonsillectomy or oxygen supplementation may result in a significant increase in mean nocturnal oxygen saturation but effective clinical implications remain still unclear.

Use of Actigraphy for the Evaluation of Sleep Disorders and Circadian Rhythm Sleep-Wake Disorders: An American Academy of Sleep Medicine Systematic Review, Meta-Analysis, and GRADE Assessment

INTRODUCTION

The purpose of this systematic review is to provide supporting evidence for a clinical practice guideline on the use of actigraphy.

METHODS

The American Academy of Sleep Medicine commissioned a task force of experts in sleep medicine. A systematic review was conducted to identify studies that compared the use of actigraphy, sleep logs, and/or polysomnography. Statistical analyses were performed to determine the clinical significance of using actigraphy as an objective measure of sleep and circadian parameters. Finally, the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) process was used to assess the evidence for making recommendations.

RESULTS

The literature search resulted in 81 studies that met inclusion criteria; all 81 studies provided data suitable for statistical analyses. These data demonstrate that actigraphy provides consistent objective data that is often unique from patient-reported sleep logs for some sleep parameters in adult and pediatric patients with suspected or diagnosed insomnia, circadian rhythm sleep-wake disorders, sleep-disordered breathing, central disorders of hypersomnolence, and adults with insufficient sleep syndrome. These data also demonstrate that actigraphy is not a reliable measure of periodic limb movements in adult and pediatric patients. The task force provided a detailed summary of the evidence along with the quality of evidence, the balance of benefits and harms, patient values and preferences, and resource use considerations.

Sleep Problem Risk for Adolescents With Sickle Cell Disease: Sociodemographic, Physical, and Disease-related Correlates

The aims of the current study were to investigate whether SCD incurs an additional risk for poor sleep over and above the influence of sociodemographic factors (ie, race and sex) during adolescence, and to explore the relationships between sociodemographic, physical (ie, age and pubertal status), and disease-related factors (ie, SCD genotype and hydroxyurea use) on sleep problem risk during adolescence. Black adolescents (age, 12 to 17 y) with SCD (n=53) were recruited from regional pediatric SCD clinics in the southeast and a sample of healthy black adolescents (n=160) were recruited from middle and high schools. Regression analyses indicated that SCD was uniquely related to sleeping more, and worse sleep quality over and above the influence of sociodemographic factors. Having a more severe SCD genotype was related to worse sleep quality and higher pubertal status was related to sleeping longer during the week. Results indicate the need for systematic assessments of sleep problems, with more a focus on youth with more severe genotypes and higher pubertal status. Future research should focus on characterizing trajectories of sleep problems in this population, identifying key risk factors, and elucidating mechanisms linking risk factors to sleep problem risk to aid in tailoring interventions for this population.

Evaluation of Periodic Limb Movements in Sleep and Iron Status in Children With Autism

OBJECTIVE

Recent data suggest that both disordered sleep and low serum iron occur more frequently in children with autism compared with children with typical development. Iron deficiency has been linked to specific sleep disorders. The goal of the current study was to evaluate periodic limb movements in sleep and iron status in a group of children with autism compared with typically developing children and children with nonautism developmental delay to determine if iron status correlated with polysomnographic measures of latency and continuity and periodic limb movements in sleep.

METHODS

A total of 102 children (68 with autism, 18 typically developing, 16 with developmental delay) aged 2 to 7 years underwent a one-night modified polysomnography study and phlebotomy at the National Institutes of Health to measure serum markers of iron status (ferritin, iron, transferrin, percent transferrin saturation).

RESULTS

No serum iron marker was associated with periodic limb movements of sleep or any other sleep parameter; this did not differ among the diagnostic groups. No significant differences among groups were observed on serum iron markers or most polysomnogram parameters: periodic limb movements in sleep, periodic limb movements index, wake after sleep onset, or sleep efficiency. Children in the autism group had significantly less total sleep time. Serum ferritin was uniformly low across groups.

CONCLUSIONS

This study found no evidence that serum ferritin is associated with polysomnogram measures of latency or sleep continuity or that young children with autism are at increased risk for higher periodic limb movements index compared with typically developing and developmental delay peers.

Hemoglobinopathies and sleep--The road less traveled

Sickle cell disease and thalassemia are common hereditary blood disorders associated with increased systemic inflammation, tissue hypoxia, endothelial dysfunction and end-organ damage, the latter accounting for the substantial morbidity and abbreviated lifespan associated with these conditions. Sleep perturbations in general, and sleep-disordered breathing in particular are also highly prevalent conditions and the mechanisms underlying their widespread end-organ morbidities markedly and intriguingly overlap with the very same pathways implicated in the hemoglobinopathies. However, little attention has been given to date to the potential contributing role of sleep disorders to sickle cell disease manifestations. Here, we comprehensively review the pathophysiological mechanisms and clinical manifestations linking disturbed sleep and hemoglobinopathies, with special emphasis on sickle cell disease. In addition to a broad summary of the available evidence, we identify many of the research gaps that require attention and future investigation, and provide the scientific contextual setting that should enable opportunities to investigate the intertwined pathophysiological mechanisms and clinical outcomes of sleep disorders and hemoglobinopathies.

Leg actigraphy to quantify periodic limb movements of sleep: a systematic review and meta-analysis

Periodic limb movements of sleep (PLMS) are repetitive, stereotyped movements that can disrupt sleep and result in insomnia, non-restorative sleep, and/or daytime sleepiness. Currently, polysomnography is the gold standard and only clinically acceptable means of quantifying PLMS. Leg-worn actigraphy is an alternative method of measuring PLMS, which may circumvent many of the economic and technical limitations of polysomnography to quantify nocturnal leg movements. However, the use of leg actigraphy as a diagnostic means of assessing PLMS has not been systematically evaluated. In this review, the use of leg-worn actigraphy to measure PLMS is systematically evaluated, using both qualitative and quantitative assessment. Findings demonstrate significant heterogeneity among a limited number of studies in terms of type of actigraph utilized, position of the device on the lower extremity, and methods employed to count PLMS. In general, common accelerometers vary in their sensitivity and specificity to detect PLMS, which is likely related to the technical specifications of a given device. A current limitation in the ability to combine data from actigraphs placed on both legs is also a significant barrier to their use in clinical settings. Further research is required to determine the optimal methods to quantify PLMS using leg actigraphy, as well as specific clinical situations in which these devices may prove most useful.