Enuresis associated with sleep disordered breathing in children with sickle cell anemia

Nocturnal hypoxaemia is common in adults with sickle cell anaemia

The symptoms and sequelae of sickle cell anaemia (SCA) are caused by the polymerization of deoxygenated sickle haemoglobin, and people with SCA may be uniquely susceptible to adverse outcomes from hypoxia and haemoglobin desaturation. We examined by oximetry adults (aged 18-45 years) with SCA presenting symptoms indicative of polysomnography, at a single institution, irrespective of treatment, for nocturnal hypoxaemia. Clinical labs and blood for in vitro assessments were taken upon enrolment and after 8-12 weeks of oxygen therapy or observation. Of 21 screened participants, nine (43%) had sufficient nocturnal hypoxaemia to warrant oxygen therapy (≥5 min at SpO2 ≤ 88%). Time spent at SpO2 ≤ 88% associated with age (p = 0.0092), annual hospitalizations (p = 0.0018) and anaemia (p = 0.0139), as well as plasma levels of TNFα (p = 0.0019) and IL-4 (p = 0.0147). Longitudinal analysis showed that WBC significantly decreased during the follow-up period in hypoxic individuals but not in non-hypoxic individuals (p = 0.0361 and p = 0.6969 respectively). Plasma levels of CCL2 and IL-1ra tended to increase, while levels of red blood cell reactive oxygen species tended to decrease with oxygen therapy. Overall, nocturnal hypoxaemia was common in this pilot study population and associated with plausible clinical comorbidities; oxygen therapy may decrease inflammation and oxidative damage in hypoxic individuals.

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 Role of Hyposthenuria in Enuresis Among Paediatric Patients With Sickle Cell Disease

Objectives

Enuresis is common among children with sickle cell disease (SCD). Many risk factors have been postulated, but its relation to hyposthenuria is debatable. This study aimed to determine the prevalence of enuresis in children with SCD in Basrah, Iraq, and to examine its relation with hyposthenuria.

Methods

A cross-sectional epidemiological study was performed on children with SCD who met the inclusion criteria at the Basrah Center for Hereditary Blood Diseases from December 2020 to May 2021. A questionnaire was used to collect relevant data. Blood samples were tested for haemoglobin genotype, certain blood indices and serum haemoglobin. Urine was tested for albumin and creatinine, and the specific gravity was measured using urine dipsticks. The relationships between enuresis and various sociodemographic and clinical variables were assessed. Binary logistic regression analysis was done to examine the independent risk factors of enuresis.

Results

A total of 161 out of 200 eligible children were included in this study (response rate: 80.5%). The majority of participants (60.9%) were males. The mean age of the participants was 10.9 ± 2.9 years. Enuresis was reported in 50 (31.1%) patients. The independent risk factors for enuresis included family history of enuresis (adjusted odds ratio [OR] = 5.94, 95% confidence interval [CI]: 2.54-13.89; P <0.001), hyposthenuria (OR = 3.76, 95% CI: 1.25-11.30; P = 0.018) and sleep disorders (OR = 2.90, 95% CI: 1.19-7.06; P = 0.019.

Conclusion

Enuresis is common among children with SCD in Basrah, Iraq. Hyposthenuria was significantly associated with enuresis. Family history of enuresis and sleep disorders were also found to be significantly related to enuresis.

Enuresis and overactive bladder in sickle cell patients: a narrative review of the literature

OBJECTIVE

The aim of this review is to clarify the prevalence, pathophysiology and clinical presentation of enuresis and overactive bladder in sickle cell patients.

MATERIALS AND METHODS

This narrative review of the literature was conducted in March 2022 by running a search in PubMed, Embase, Scopus and Cochrane databases without publication date limitation, using the following keywords: enuresis or nocturia or overactive bladder or urinary incontinence or bedwetting and sickle cell.

RESULTS

Eight cross-sectional studies were included, six of which had a non-sickle cell control population. The prevalence of enuresis in children and adolescents with sickle cell disease ranged from 20.3 to 49.4%. It decreased with age to 2.9% in adult sickle cell patients. Enuresis in sickle cell patients has been attributed to several causes, including lack of urine concentration with nocturnal polyuria, reduced bladder capacity, nocturnal bladder hyperactivity, sleep and/or respiratory disorders are likely causes of enuresis in sickle cell patients. The prevalence of overactive bladder is three times higher in sickle cell patients than in control groups. The latter is also observed three times more frequently in men who have had prior episodes of priapism.

CONCLUSION

Enuresis and overactive bladder are common in sickle cell patients. Several mechanisms have been described to try to explain enuresis in sickle cell patients but overactive bladder seems to play a major role. Studies evaluating the efficacy of certain experimentally validated treatments must be carried out to improve the management of these complications which affect the quality of life of sickle cell patients.

Considerations for Selecting Cognitive Endpoints and Psychological Patient-Reported Outcomes for Clinical Trials in Pediatric Patients With Sickle Cell Disease

Pediatric patients with sickle cell disease (SCD) experience a range of medical complications that result in significant morbidity and mortality. Recent advances in prophylactic and curative treatment approaches have highlighted the need for sensitive and clinically-meaningful trial endpoints. The detrimental effects of cognitive and psychological difficulties on social and economic mobility are well described. Although numerous reviews have assessed cognitive outcomes in other rare genetic disorders, SCD has not received the same focus. This review describes the cognitive (i.e., executive function and processing speed) and psychological domains (i.e., depression and anxiety) that are consistently associated with SCD pathology and, therefore, may be of particular interest as clinical trial endpoints. We then discuss corresponding well-validated and reliable cognitive tests and patient-reported outcomes (PROs) that may be appropriate for clinical trials given their robust psychometric properties, ease of administration, and previous use in the SCD population. Further, we provide a discussion of potential pitfalls and considerations to guide endpoint selection. In line with the move toward patient-centered medicine, we identify specific tests (e.g., NIH Toolbox Cognition Module, Wechsler Cancellation Test) and psychological PROs (e.g., PROMIS depression and anxiety scales) that are sensitive to SCD morbidity and have the potential to capture changes that are clinically meaningful in the context of patients' day to day lives. In particularly vulnerable cognitive domains, such as executive function, we highlight the advantages of composite over single-test scores within the context of trials. We also identify general (i.e., practice effects, disease heterogeneity) and SCD-specific considerations (i.e., genotype, treatment course, and disease course, including degree of neurologic, pain, and sleep morbidity) for trial measures. Executive function composites hold particular promise as trial endpoints that are clinically meaningful, amenable to change, relatively easy to collect, and can be incorporated into the routine care of patients with SCD in various settings and countries.

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.

Nocturnal Enuresis in Sickle Cell: Sociodemographic, Medical, and Quality of Life Factors

OBJECTIVE

Nocturnal enuresis is more prevalent in youth with sickle cell disease (SCD) compared to the general population. The purpose of this study is to estimate prevalence of nocturnal enuresis using diagnostic criteria and identify associated sociodemographic, medical, and health-related quality of life (HRQOL) factors.

METHODS

Youth with SCD (N = 248; ages 6.00-17.99 years) and their caregivers completed semi-structured interviews and questionnaires. HRQOL was measured using the Pediatric Quality of Life (PedsQL) Inventory. Medical information was abstracted from medical record. We generated multivariable logistic regression models to examine associations between factors and current nocturnal enuresis and nocturnal enuresis occurring any time in the past (lifetime).

RESULTS

Among participants (mean age, 11.3 ± 3.6 years; 50.8% male), 21.4% reported current nocturnal enuresis and 46% reported lifetime nocturnal enuresis. Male sex [odds ratio (OR), 2.57; p = .001], difficulty arousing from sleep (OR, 3.57; p < .001), higher school functioning HRQOL (OR, 1.02; p = .014), and higher fetal hemoglobin levels (OR, 1.03; p = .048) were associated with lifetime nocturnal enuresis. Younger age (OR, 1.16; p = .005), higher youth-reported fatigue (OR, 1.01; p = .045), difficulty arousing from sleep (OR, 4.92; p < .001), and higher lactate dehydrogenase levels (OR, 1.00; p = .042) were associated with current nocturnal enuresis.

CONCLUSIONS

Nocturnal enuresis is prevalent in youth with SCD and is associated with HRQOL, diminished sleep, greater fatigue, and disease severity markers. Routine assessment of sleep behaviors and fatigue are necessary when treating patients with SCD to understand the impact of nocturnal enuresis on HRQOL.

Developmental Profile of Sleep and Its Potential Impact on Daytime Functioning from Childhood to Adulthood in Sickle Cell Anaemia

Young individuals with sickle cell anaemia (SCA) experience sleep disturbances and often experience daytime tiredness, which in turn may impact on their daytime functioning and academic attainment, but there are few longitudinal data.

METHODS

Data on sleep habits and behaviour were taken on the same day as an in-hospital polysomnography. This study assesses the developmental sleep profiles of children and young adults aged 4-23 years old with SCA. We examined retrospective polysomnography (PSG) and questionnaire data.

RESULTS

A total of 256 children with a median age of 10.67 years (130 male) were recruited and 179 returned for PSG 1.80-6.72 years later. Later bedtimes and a decrease in total sleep time (TST) were observed. Sleep disturbances, e.g., parasomnias and night waking, were highest in preschool children and young adults at their first visit. Participants with lower sleep quality, more movement during the night and increased night waking experienced daytime sleepiness, potentially an indicator of lower daytime functioning. Factors influencing sleep quantity included age, hydroxyurea prescription, mean overnight oxygen saturation, sleep onset latency, periodic limb movement, socioeconomic status and night waking.

CONCLUSION

Sleep serves an important role for daytime functioning in SCA; hence, quantitative (i.e., PSG for clinical symptoms, e.g., sleep-disordered breathing, nocturnal limb movement) and qualitative (i.e., questionnaires for habitual sleep behaviour) assessments of sleep should be mutually considered to guide interventions.

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.

American Society of Hematology 2019 guidelines for sickle cell disease: cardiopulmonary and kidney disease

BACKGROUND

Prevention and management of end-organ disease represent major challenges facing providers of children and adults with sickle cell disease (SCD). Uncertainty and variability in the screening, diagnosis, and management of cardiopulmonary and renal complications in SCD lead to varying outcomes for affected individuals.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about screening, diagnosis, and management of cardiopulmonary and renal complications of SCD.

METHODS

ASH formed a multidisciplinary guideline panel that included 2 patient representatives and was balanced to minimize potential bias from conflicts of interest. The Mayo Evidence-Based Practice Research Program supported the guideline development process, including performing systematic evidence reviews up to September 2017. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE evidence-to-decision frameworks, to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 10 recommendations for screening, diagnosis, and management of cardiopulmonary and renal complications of SCD. Recommendations related to anticoagulation duration for adults with SCD and venous thromboembolism were also developed.

CONCLUSIONS

Most recommendations were conditional due to a paucity of direct, high-quality evidence for outcomes of interest. Future research was identified, including the need for prospective studies to better understand the natural history of cardiopulmonary and renal disease, their relationship to patient-important outcomes, and optimal management.

Pediatric sickle cell disease and obstructive sleep apnea: A cross-sectional study in a tertiary pediatric center in Saudi Arabia

OBJECTIVE

The aim of the study was to evaluate snoring and obstructive sleep apnea (OSA) in Saudi children with sickle cell disease (SCD).

MATERIALS AND METHODS

This cross-sectional study was conducted among children with SCD attending a hematology clinic were recruited. Demographics, clinical data, and sleep questionnaires were collected and overnight polysomnographies performed.

RESULTS

Seventy children (31 of whom were females) with SCD were included in the study. Their median (interquartile) age was 9 (6.5, 11) years and their body mass index z-score was -1.2 (-2.0, -0.4). Seventy-four percent of SCD patients snored and 32 (46%) had evidence of OSA (obstructive apnea-hypopnea index [OAHI] ≥2 events per hour of sleep), 13 of whom had moderate OSA (OAHI ≥5 and <10 events per hour of sleep) and 10 had severe OSA (OAHI ≥10 events per hour of sleep).

CONCLUSION

Snoring and the proportion of OSA were high in children with SCD. This underlines the importance of screening for OSA in all children with SCD.

Sleep phenotype in the Townes mouse model of sickle cell disease

Purpose

Patients with sickle cell disease (SCD) regularly experience abnormal sleep, characterized by frequent arousals and reduced total sleep time. However, obstructive sleep apnea syndrome (OSAS) is a common comorbidity of SCD, making it unclear whether the disease per se is impacting sleep, or sleep disruption is secondary to the presence of OSAS. Thus, we assessed sleep, independent of OSAS, using a mouse model of SCD.

Methods

Sleep was compared between 10-to-12-week-old Townes knockout-transgenic mice with the sickle cell phenotype SS (n = 6) and Townes mice with sickle cell trait AS (n = 6; control). The mice underwent chronic polysomnographic electrode implantation (4EEG/2EMG) to assess sleep architecture.

Results

The SS mice had significantly lower hemoglobin concentration compared to control AS mice (7.3 ± 1.3 vs. 12.9 ± 1.7 g/dL; p < 0.01), consistent with the expected SCD phenotype. SS mice exhibited significantly decreased total NREM sleep time (45.0 ± 0.7 vs. 53.0 ± 1.3% 24 h sleep time; p < 0.01), but no change in total REM sleep time compared to the AS mice. The SS mice took longer to resume sleep after a wake period compared to the AS mice (3.2 ± 0.3 min vs. 1.9 ± 0.2 min; p < 0.05). Unexpectedly, SS mice experienced fewer arousals compared to AS mice (19.0 ± 0.9 vs. 23.3 ± 2.1 arousals/h of sleep; p = 0.031).

Conclusions

The presence of decreased total NREM sleep associated with reduced arousals, in the absence of OSAS, suggests a distinctive underlying sleep phenotype in a mouse model of SCD.

Enuresis in children and adolescents with sickle cell anaemia is more frequent and substantially different from the general population

Background

No large studies have examined the prevalence of enuresis, its various forms and risk factors in children with sickle cell anaemia (SCA) in Sub-Saharan Africa using standardised definitions. We determined age and gender-specific prevalence of enuresis and compared the nature of enuresis in children with and without SCA. We also identified predictors of enuresis in children with SCA.

Methods

Caregivers of children with SCA attending a tertiary centre haematology clinic in Nigeria were interviewed using a questionnaire. In addition, a separate questionnaire was completed for every sibling aged 5–17 years whose haemoglobin genotype was known. Enuresis and its various forms were defined using the definitions of the International Children’s Continence Society.

Results

The study involved 243 children with SCA and 243 controls matched for age and sex. The mean age of the study cohort was 9.9 (3.4). Females made up 45.7% of the cohorts. The prevalence of enuresis was 49.4% and 29.6% in children with and without SCA, respectively (p = 0.009). In both groups, the prevalence of enuresis declined with age but remained five times higher at 25% in children with SCA aged 14–17 years compared with controls. Also, children with SCA and enuresis were older, more likely to have non-monosymptomatic enuresis and wet at least three nights per week than controls. Independent predictors of enuresis in children with SCA were a family history of enuresis and young age.

Conclusion

Children with SCA had more frequent and more severe enuresis which persisted to late adolescence than age and sex-matched controls. These features indicate a subset of enuresis that is difficult to treat in the general population. Young age and enuresis in a family member define a subset of children with SCA more likely to have enuresis. Healthcare workers need to discuss enuresis with parents of children with SCA and offer referral to continence services.

Transfusion-related adverse events are decreased in pregnant women with sickle cell disease by a change in policy from systematic transfusion to prophylactic oxygen therapy at home: A retrospective survey by the international sickle cell disease observatory

Sickle cell disease (SCD) in pregnancy can be associated with adverse maternal and perinatal outcomes. Furthermore, complications of SCD can be aggravated by pregnancy. Optimal prenatal care aims to decrease the occurrence of maternal and fetal complications. A retrospective, French, two-center study compared two care strategies for pregnant women with SCD over two time periods. In the first study period (2005-2010), the women were systematically offered prophylactic transfusions. In the second study period (2011-2014), a targeted transfusion strategy was applied whenever possible, and home-based prophylactic nocturnal oxygen therapy was offered to all the pregnant women. The two periods did not differ significantly in terms of the incidence of vaso-occlusive events. Maternal mortality, perinatal mortality, and obstetric complication rates were also similar in the two periods, as was the incidence of post-transfusion complications (6.1% in 2005-2010 and 1.3% in 2011-2014, P = .15), although no de novo alloimmunizations or delayed hemolysis transfusion reactions were observed in the second period. The results of this preliminary, retrospective study indicate that targeted transfusion plus home-based prophylactic nocturnal oxygen therapy is safe and may decrease transfusion requirements and transfusion-associated complications.

Sleep-disordered breathing in patients with sickle cell disease

Sickle cell disease is one of the most common hereditary hemoglobinopathies worldwide, and its vaso-occlusive and hemolytic crises cause considerable patient morbidity. A growing body of evidence has shown that sleep-disordered breathing, and in particular, obstructive sleep apnea, occurs at high frequency in the sickle cell population, and that there is significant overlap in the underlying pathophysiology of these two conditions. Through a variety of mechanisms including nocturnal hypoxemia and increased oxidative stress, production of pro-inflammatory cytokines, and endothelial dysfunction, sickle cell anemia and sleep-disordered breathing potentiate each other's clinical effects and end-organ complications. Here, we will review the shared pathophysiologic mechanisms of these conditions and discuss their clinical sequelae. We will also examine the results of studies that have been carried out with clinical intervention of nocturnal hypoxemia in patients with sickle cell disease in the attempts to overcome the complications of the disease. Finally, we will propose the areas of investigation that merit further investigations in future in patients with sickle cell disease and sleep-disordered breathing.

Parent reported sleep problems in preschool children with sickle cell anemia and controls in East London

Snoring and poor sleep may affect cognition, particularly in young children with chronic conditions. Parents of London preschoolers with sickle cell anemia (SCA; n = 22), matched controls (n = 24), and unselected typically developing (n = 142) preschoolers completed sleep questionnaires. Preschoolers with SCA had significantly more sleep problems when compared to matched controls and the larger population. Snoring occurred at least one to two nights a week for 79% of the SCA group. This is compared with 25% of matched controls and 33% of larger population. Randomized controlled trials to improve sleep in young children with SCA already at-risk for cognitive dysfunction should be considered.

Chronic complications and quality of life of patients living with sickle cell disease and receiving care in three hospitals in Cameroon: a cross-sectional study

BACKGROUND

Sickle Cell Disease (SCD) is associated with chronic multisystem complications that significantly influence the quality of life (QOL) of patients early in their life. Although sub-Saharan Africa bears 75% of the global burden of SCD, there is a paucity of data on these complications and their effects on the QOL. We aimed to record these chronic complications, to estimate the QOL, and to identify the corresponding risk factors in patients with SCD receiving care in three hospitals in Cameroon.

METHODS

In this cross-sectional study, a questionnaire was used to collect data from consecutive consenting patients. Information recorded included data on the yearly frequency of painful crisis, the types of SCD, and the occurrence of chronic complications. A 36-Item Short Form (SF-36) standard questionnaire that examines the level of physical and mental well-being, was administered to all eligible participants. Data were analyzed with STATA® software.

RESULTS

Of 175 participants included, 93 (53.1%) were female and 111 (aged ≥14 years) were eligible for QOL assessment. The median (interquartile range, IQR) age at diagnosis was 4.0 (2.0-8.0) years and the median (IQR) number of yearly painful crisis was 3.0 (1.0-7.0). The most frequent chronic complications reported were: nocturnal enuresis, chronic leg ulcers, osteomyelitis and priapism (30.9%, 24.6%, 19.4%, and 18.3% respectively). The prevalence of stroke and avascular necrosis of the hip were 8.0% and 13.1% respectively. The median (IQR) physical and mental scores were 47.3 (43.9-58.5) and 41.0 (38.8-44.6) respectively. Age and chronic complications such as stroke and avascular necrosis were independently associated with poor QOL.

CONCLUSIONS

In this population of patients living with SCD, chronic complications are frequent and their QOL is consequently poor. Our results highlight the need for national guidelines for SCD control, which should include new-born screening programs and strategies to prevent chronic complications.

Higher nocturnal and awake oxygen saturations in children with sickle cell disease receiving hydroxyurea therapy

RATIONALE

Obstructive sleep apnea and intermittent nocturnal oxygen desaturations are highly prevalent in children with sickle cell disease and have been reported to contribute to associated morbidity, including vasoocclusive disease. Hydroxyurea (HU) is increasingly used to treat children with sickle cell disease and has been shown to decrease the number and severity of vasoocclusive crises. Although there has been an increase in the use of HU, the impact of HU on the prevalence of obstructive sleep apnea and nocturnal hypoxia are not well documented.

OBJECTIVES

To evaluate whether the use of HU is associated with a decreased frequency of obstructive sleep apnea and higher nocturnal and awake oxygen saturations (SaO2) in children with sickle cell disease.

METHODS

This was a retrospective, cross-sectional review of children with sickle cell disease referred to the sleep laboratory at the Hospital for Sick Children, Toronto, Canada. Polysomnogram data in children with sickle cell disease receiving HU therapy were compared with those not prescribed HU.

MEASUREMENTS AND MAIN RESULTS

Children with sickle cell disease receiving HU therapy (HU group, n = 37) were matched with children not receiving HU (no-HU group, n = 104). Obstructive sleep apnea was diagnosed in 14 of 37 (38%) and 54 of 104 (52%) in the HU group and no-HU groups, respectively (P = 0.14). The median obstructive apnea-hypopnea index was 0.9 and 1.9 events/h in the HU group and the no-HU group, respectively (P = 0.28). The HU group compared with the no-HU group had a significantly higher median awake SaO2 (98.6 and 96.2%, respectively; P < 0.0001), a significantly higher median sleep SaO2 (98.4 and 96.1%, respectively; P < 0.001), and a significantly higher nadir SaO2 while asleep (91.4 and 85.0%, respectively; P = 0.0002).

CONCLUSIONS

In children with sickle cell disease, the use of HU was associated with an increase in awake and nocturnal SaO2, despite there being no difference in the frequency of obstructive sleep apnea and the severity of the obstructive apnea-hypopnea index. Improving nocturnal SaO2 may be an important mechanism of action of HU therapy. The use of HU to improve nocturnal saturations across the severity spectrum of sickle cell disease may be beneficial in decreasing morbidities related to sickle cell disease.

Chronic Pulmonary Complications of Sickle Cell Disease

Sickle cell disease (SCD), the most common genetic hemolytic anemia worldwide, affects 250,000 births annually. In the United States, SCD affects approximately 100,000 individuals, most of African descent. Hemoglobin S (HbS) results from a glutamate-to-valine mutation of the sixth codon of the β-hemoglobin allele; the homozygous genotype (HbSS) is associated with the most prevalent and severe form of the disease. Other SCD genotypes include HbSC, composed of one HbS allele and one HbC (glutamate-to-lysine mutation) allele; and HbS-β-thalassemia(0) or HbS-β-thalassemia(+), composed of one HbS allele and one β-thalassemia allele with absent or reduced β-chain production, respectively. Despite advances in care, median survival remains in the fifth decade, due in large part to chronic complications of the disease. Chronic pulmonary complications in SCD are major contributors to this early mortality. Although our understanding of these conditions has improved much over the past 10 to 15 years, there remains no specific treatment for pulmonary complications of SCD. It is unclear whether conventional treatment regimens directed at non-SCD populations have equivalent efficacy in patients with SCD. This represents a critical research need. In this review, the authors review the state-of-the-art understanding of the following pulmonary complications of SCD: (1) pulmonary hypertension; (2) venous thromboembolic disease; (3) sleep-disordered breathing; (4) asthma and recurrent wheezing; and (5) pulmonary function abnormalities. This review highlights the advances as well as the knowledge gaps in this field to update clinicians and other health care providers and to garner research interest from the medical community.

Prevention of Morbidity in sickle cell disease--qualitative outcomes, pain and quality of life in a randomised cross-over pilot trial of overnight supplementary oxygen and auto-adjusting continuous positive airways pressure (POMS2a): study protocol for a randomised controlled trial

BACKGROUND

Sickle cell anaemia (SCA) is an inherited disorder of haemoglobin. Patients experience long-term health care problems, affecting quality of life (QOL) including frequent acute pain, which is difficult to document in trials except as hospital admissions. Pilot data suggests that overnight respiratory support, either supplementary oxygen or auto-adjusting continuous positive airways pressure (APAP), is safe and may have clinical benefit. This pilot trial aims to determine which intervention is more acceptable to participants and whether there are other advantages of one over the other, e.g. in respiratory function or haematological parameters, before conducting the Phase 2 trial of overnight respiratory support funded by the National Institutes of Health Research.

METHODS/DESIGN

This is a pilot cross-over interventional trial with the order of interventions decided by simple randomization. Ten adults (age over 18 years) and 10 children (aged between 8 and 18 years) with homozygous sickle cell disease (haemoglobin SS, HbSS), recruited regardless of symptoms of sleep-disordered breathing, will undergo overnight pulse oximetry and will have two interventions, overnight oxygen and APAP, for a week each in randomised order with a washout week between interventions. Participants will complete online diaries via an iPad throughout the 29 days of the study and will complete QOL questionnaires and have measurement of haematology, biochemistry, spirometry and lung volumes (adults only) at 3 time points, at baseline and after each intervention, as well as in-depth semi-structured qualitative interviews after each intervention, carried out by an experienced psychologist. Both qualitative and statistical methods will be used to analyze the data. The primary outcome is qualitative data looking at participant experience from the transcribed interviews after each intervention. The participant's view on feasibility, acceptability and preference will specifically be explored. The QOL, laboratory and lung function data will be compared with baseline for each arm.

DISCUSSION

Patient and public involvement is an integral part of this trial and the key outcome is the qualitative result, which is dependent on obtaining good quality data to advise on participant feasibility, acceptability and preference. This is being addressed by using a standard interview. The development of a pain endpoint is another important outcome and collecting daily measurements is likely to be challenging. Research results will be used to inform design of the Phase 2 trial.

TRIAL REGISTRATION

ISRCTN46078697 18 July 2014.

Obstructive sleep apnea and sickle cell anemia

OBJECTIVE

To ascertain the prevalence of and risk factors for obstructive sleep apnea syndrome (OSAS) in children with sickle cell anemia (SCA).

METHODS

Cross-sectional baseline data were analyzed from the Sleep and Asthma Cohort Study, a multicenter prospective study designed to evaluate the contribution of sleep and breathing abnormalities to SCA-related morbidity in children ages 4 to 18 years, unselected for OSAS symptoms or asthma. Multivariable logistic regression assessed the relationships between OSAS status on the basis of overnight in-laboratory polysomnography and putative risk factors obtained from questionnaires and direct measurements.

RESULTS

Participants included 243 children with a median age of 10 years; 50% were boys, 99% were of African heritage, and 95% were homozygous for β(S) hemoglobin. OSAS, defined by obstructive apnea hypopnea indices, was present in 100 (41%) or 25 (10%) children at cutpoints of ≥1 or ≥5, respectively. In univariate analyses, OSAS was associated with higher levels of habitual snoring, lower waking pulse oxygen saturation (Spo2), reduced lung function, less caretaker education, and non-preterm birth. Lower sleep-related Spo2 metrics were also associated with higher obstructive apnea hypopnea indices. In multivariable analyses, habitual snoring and lower waking Spo2 remained risk factors for OSAS in children with SCA.

CONCLUSIONS

The prevalence of OSAS in children with SCA is higher than in the general pediatric population. Habitual snoring and lower waking Spo2 values, data easily obtained in routine care, were the strongest OSAS risk factors. Because OSAS is a treatable condition with adverse health outcomes, greater efforts are needed to screen, diagnose, and treat OSAS in this high-risk, vulnerable population.

Obstructive sleep apnea in children: a critical update

Obstructive sleep apnea (OSA) in children is a highly prevalent disorder caused by a conglomeration of complex pathophysiological processes, leading to recurrent upper airway dysfunction during sleep. The clinical relevance of OSA resides in its association with significant morbidities that affect the cardiovascular, neurocognitive, and metabolic systems. The American Academy of Pediatrics recently reiterated its recommendations that children with symptoms and signs suggestive of OSA should be investigated with polysomnography (PSG), and treated accordingly. However, treatment decisions should not only be guided by PSG results, but should also integrate the magnitude of symptoms and the presence or absence of risk factors and signs of OSA morbidity. The first-line therapy in children with adenotonsillar hypertrophy is adenotonsillectomy, although there is increasing evidence that medical therapy, in the form of intranasal steroids or montelukast, may be considered in mild OSA. In this review, we delineate the major concepts regarding the pathophysiology of OSA, its morbidity, diagnosis, and treatment.