Asthma morbidity and treatment in children with sickle cell disease

Burden and outcome of respiratory morbidities among children and adolescents with sickle cell disease-A retrospective review of emergency presentations in some Nigerian tertiary institutions

BACKGROUND

Despite the huge burden of sickle cell disease (SCD) among Nigerian children, the burden and outcome of respiratory illnesses remain undocumented. Thus, we aimed to describe the spectrum and outcome of respiratory illnesses among SCD childrenand adolescentadmissions in ten Nigerian tertiary hospitals.

METHOD

A retrospective review of the SCD admission records of children and adolescents with a confirmed diagnosis of respiratory illnesses from 2012 to 2021 in ten tertiary health facilities across five geopolitical zones in Nigeria was conducted. The data, collectedbetween March and June 2023, included the age, sex, diagnosis, complications, duration and outcome of hospitalization.

RESULTS

Of the 72,333 paediatric admissions, 7,256 (10.0%) had SCD; the proportion of SCD from the total admission ranged from 2.1 to 16.3% in the facilities. Of the 7,256 children and adolescents with SCD, 1,213 (16.7%) had respiratory morbidities. Lower respiratory disease was the most common (70.0%) respiratory entity and the majority were pneumonia (40.1.0%), followed by acute chest syndrome (26.7%). Seventeen (1.4%) patients died; all had lower respiratory diseases [(acute chest syndrome ACS (11, 64.7%), pneumonia; 5, 29.4%, and asthma (1, 5.9%). Based on the proportion of deaths among overall SCD, the 17 death cases contributed 9.4% (95% CI 5.9 to 14.5). Factors associated with deaths included duration of hospitalization less than 72 hours and lower respiratory tract diseases.

CONCLUSION

Sickle cell disease is a major contributor to hospitalization among Nigerian children and adolescents, with high respiratory morbidity and mortality. Pneumonia and acute chest syndrome were associated with mortality, andthe highest risk of death within the first 72 hours.

Benefit of pulmonary subspecialty care for children with sickle cell disease and asthma

OBJECTIVE

Asthma is a recognized comorbidity in children with sickle cell disease (SCD). It increases the risk of acute chest syndrome (ACS), vaso-occlusive episodes, and early mortality. We aim to determine whether evaluation and management of children with SCD and asthma by a pulmonologist reduce rate of asthma exacerbation and ACS.

METHODS

The study included 192 patients with SCD (0-21 years) followed at Children's Hospital of Philadelphia Hematology between January 1, 2015, and December 31, 2018, with a diagnosis of asthma, wheeze, or cough. Patients were placed in two groups: those evaluated by a pulmonologist (SCD-A-P) and those not (SCD-A). Rates of emergency department (ED) visits and hospitalizations for asthma exacerbation and ACS were compared between groups and over time.

RESULTS

SCD-A-P patients (n = 70) were predominantly SCD type SS with lower hemoglobin and hematocrit compared to SCD-A patients (n = 122). SCD-A-P started with a higher average rate of hospital visits for asthma exacerbation and ACS per year (2.69 [1.02-4.37]) compared to SCD-A (0.43 [0.24-0.63]), (p < 0.001). For SCD-A-P patients with at least one hospital visit (n = 48), the average rate decreased from 3.93 (1.57-6.29) to 0.85 (0.48-1.23) following pulmonary consultation (p = 0.014) and was comparable to the SCD-A rate by study end.

CONCLUSION

SCD-A-P was mainly SCD type SS and had higher ED/hospitalization rates for asthma exacerbation and ACS compared to SCD-A, but the rates significantly decreased following pulmonology consultation. These findings support the pulmonologist's role in the multidisciplinary care of SCD patients and highlight the need for evidence-based asthma guidelines for children with SCD.

Feasibility and preliminary outcomes of an integrated pediatric sickle cell disease and pulmonary care clinic for children with sickle cell disease

BACKGROUND

In children with sickle cell disease (SCD), comorbid asthma is associated with increased disease severity and morbidity, but it remains underdiagnosed and optimal management paradigms are not well defined. The purpose of this study was to determine the feasibility and preliminary outcomes of an integrated pediatric SCD and pulmonary care clinic in children with SCD.

METHODS

We implemented a pre-post quality improvement (QI) project in our pediatric hematology clinic between 2017 and 2019. Guided by the chronic care model, patients who were ages 2-18 years, diagnosed with SCD and suspected pulmonary comorbidities, received care in an interdisciplinary clinic. We examined feasibility and compared clinical outcomes to 24 months prior (2015-2017) to the implementation of the integrated care model.

RESULTS

Twenty-four patients were included in the QI project: 88% (n = 21) received pulmonary function testing, 92% (n = 22) were diagnosed with asthma, and 33% (n = 8) with obstructive sleep apnea. Adherence to pulmonary appointments was increased by 81% (mean difference [MD] = 1.3, 95% confidence interval [CI] = 0.71-1.92; P < .001). Unplanned acute health care utilization was reduced by 59% (MD = 2.9, 95% CI = 1.14-4.69; P < .01) and packed red blood cell transfusion was reduced by 81% (MD = 1.38, 95% CI = 0.71-2.04; P < .001).

CONCLUSION

Asthma is prevalent in children with SCD, and interdisciplinary clinics can improve access to subspecialty pulmonary care and reduce unplanned acute care. Additional patients and a longer follow-up period are required to determine the true treatment effect.

Asthma, allergic sensitization and lung function in sickle cell disease

BACKGROUND

Pulmonary disease is a frequent acute and chronic manifestation in sickle cell disease (SCD), presenting high morbidity and mortality.

OBJECTIVES

To identify the prevalence and association of asthma, allergic sensitization and altered pulmonary function in patients with SCD (SS and Sβ^o).

METHODS

A single-center, cross-sectional study was conducted, in which 70 patients with SCD and 44 controls, aged six to 18 years, responded to the questionnaire of the International Study of Asthma and Allergies in Childhood (ISAAC), complemented with an anamnesis regarding the associated clinical outcomes. All patients underwent immediate hypersensitivity skin tests with aeroallergens and a pulmonary function evaluation (spirometry). Regarding the statistical analysis, parametric and non-parametric methods were used, depending on the variables studied. Tests were considered significant when p<0.05.

RESULTS

There was no significant difference between the patients and controls regarding the prevalence of asthma and allergic sensitization (p>0.05). The number of occurrences of acute chest syndrome per patient per year was significantly higher for asthmatic patients than for non-asthmatic patients (p=0.04). Obstructive pulmonary function occurred in 30.9% of the patients and in 5.4% of the controls, and restrictive pulmonary function occurred in 5.5% of the patients and 5.4% of the controls. Asthma and wheezing in the last 12months had significant associations with obstructive pulmonary function (p=0.014 and p=0.027, respectively).

CONCLUSIONS

The occurrence of asthma, allergic sensitization and alteration in lung function in patients with SCD reinforces the importance of routine monitoring of these diagnoses, which allows for early treatment and prevention of the evolution of pulmonary disease in adulthood.

Validation of the breathmobile case identification survey for asthma screening in children with sickle cell disease

Background: Asthma is a chronic airway disorder with variable/recurring symptoms, airflow obstruction, bronchial hyperresponsiveness, and an inflammation. The expert panel report of the National Heart Lung and Blood Institute recommends asthma screening in sickle cell disease (SCD); however, specific approach is not mentioned. We hypothesize that the breathmobile case identification survey (BCIS) is a valid asthma screening tool in children with SCD.Methods: This prospective, single-center study enrolled 129 SCD patients aged 5 to 18 years from March 2016 to March 2018. All patients completed BCIS, spirometry, and fractional exhaled nitric oxide (FeNO). A single pulmonologist blinded to the BCIS results evaluated patients for asthma.Results: Asthma prevalence was 41%. Male gender (60.4%; p = 0.041), allergic rhinitis (86.8%; p < 0.01), hydroxyurea usage (73.6%; p < 0.01), and family history of asthma (34%; p < 0.01) were higher but not self-reported parental asthma history, eczema, and tobacco smoke exposure in the asthma group compared to the nonasthma group. FEV₁ (p = 0.003), FVC (p = 0.02), FEV₁/FVC (p = 0.053), and FEF_25-75% (p = 0.02) were lower in asthma. FeNO levels were comparable in both groups. The sensitivity, specificity, positive predictive value, and negative predictive value of the abbreviated BCIS were 67.3%, 90.8%, 83.3%, and 80.2% for asthma; and 82.1%, 90.8%, 76.7%, and 93.2% for persistent asthma, respectively. Persistent asthma patients had a trend of higher hydroxyurea use (82.8% vs. 58.3%; p = 0.049) and tobacco smoke exposure (55.2% vs. 29.2%; p = 0.057) compared to intermittent asthma.Conclusion: We have validated the BCIS to screen for asthma in SCD. Spirometry but not FeNO may support an asthma diagnosis.

Performance of ICD-10-CM diagnosis codes for identifying children with Sickle Cell Anemia

OBJECTIVE

To develop, test, and validate the performance of ICD-10-CM claims-based case definitions for identifying children with sickle cell anemia (SCA).

DATA SOURCES

Medicaid administrative claims (2016) for children <18 years with potential SCA (any D57x diagnosis code) and newborn screening records from Michigan and New York State.

STUDY DESIGN

This study is a secondary data analysis.

DATA COLLECTION/EXTRACTION METHODS

Using specific SCA-related (D5700, D5701, and D5702) and nonspecific (D571) diagnosis codes, 23 SCA case definitions were applied to Michigan Medicaid claims (2016) to identify children with SCA. Measures of performance (sensitivity, specificity, area under the ROC curve) were calculated using newborn screening results as the gold standard. A parallel analysis was conducted using New York State Medicaid claims and newborn screening data.

PRINCIPAL FINDINGS

In Michigan Medicaid, 1597 children had ≥1 D57x claim; 280 (18 percent) were diagnosed with SCA. Measures of performance varied, with sensitivities from 0.02 to 0.97 and specificities from 0.88 to 1.0. The case definition of ≥1 outpatient visit with a SCA-related or D571 code had the highest area under the ROC curve, with a sensitivity of 95 percent and specificity of 92 percent. The same definition also had the highest performance in New York Medicaid (n = 2454), with a sensitivity of 94 percent and specificity of 86 percent.

CONCLUSIONS

Children with SCA can be accurately identified in administrative claims using this straightforward case definition. This methodology can be used to monitor trends and use of health services after transition to ICD-10-CM.

Sickle Cell Disease: A Primer for Primary Care Providers

Sickle cell disease is an autosomal recessive disorder with significant global impact. This disorder causes the production of a dysfunctional hemoglobin, which leads to sickling of erythrocytes and ultimately hemolysis, endothelial dysfunction, vaso-occlusion, and sterile inflammation. These cellular level processes produce end-organ changes that ultimately result in specific risks and preventive care needs, unique emergency situations, and long-term complications for patients. Options for the treatment of sickle cell disease are increasing. Thus far, hydroxyurea is the most proven treatment and has been shown to reduce vaso-occlusive crises in children and adults and preserve organ function. Other therapies, both disease modifying and curative, are emerging and will hopefully have a substantial effect in the near future. [Pediatr Ann. 2020;49(1):e43-e49.].

Early initiation of inhaled corticosteroids does not decrease acute chest syndrome morbidity in pediatric patients with sickle cell disease

Acute chest syndrome (ACS) is a leading cause of mortality in patients with sickle cell disease (SCD). Systemic corticosteroids decrease ACS severity, but the risk of readmission for vaso-occlusive crises (VOC) has limited their use. The efficacy of inhaled corticosteroids (ICS) as a safer alternative is currently unknown. An observational, historic cohort study compared patients with SCD with ACS who received ICS at admission (ICS) to those who did not (non-ICS). Outcome measures included rates of transfusion, oxygen requirement, BiPAP initiation, PICU transfer, intubation, readmission, hospital cost, and length of stay. One hundred twenty patients with SCD (55 non-ICS, 65 ICS) were included. A significantly higher proportion of the non-ICS group had bilateral infiltrates, but fewer had asthma. More children in the ICS group had BiPAP initiated, however transfer to the PICU, intubation, transfusion rates, oxygen requirement, hospital cost, length of stay, and readmission rates did not differ between groups. Regression analysis did not reveal any differences in outcomes, nor were outcomes changed when patients were separated based on the presence or absence of asthma. In this observational cohort study, ICS did not demonstrate a significant reduction in ACS morbidity, though ICS use should be studied in a prospective manner.

Asthma Screening in Pediatric Sickle Cell Disease: A Clinic-Based Program Using Questionnaires and Spirometry

A clinician diagnosis of asthma is associated with increased morbidity and mortality in people with sickle cell disease (SCD). We hypothesized that a screening program would help identify children with asthma needing referral to pulmonary clinic. We conducted a single-center project to screen patients with SCD for asthma using a previously validated questionnaire (Breathmobile) and for pulmonary function abnormalities with portable spirometry. Participants with a positive questionnaire and/or abnormal spirometry were referred to pediatric pulmonary clinic. We evaluated clinical associations with abnormal spirometry and questionnaire responses. Of the 157 participants, 58 (37%) had a positive asthma screening questionnaire. Interpretable spirometry was available for 105 (83% of those eligible) and of these, 35 (34%) had abnormal results. The asthma questionnaire was 87.5% sensitive [95% confidence interval (CI) 74.8-95.3] and 85.3% specific (95% CI 77.3-91.4) to detect a clinician diagnosis of asthma. Participants with positive questionnaires were older (mean age 12.2 vs. 9.9 years, P = 0.012). Spirometry identified 16 additional participants who had normal asthma questionnaires. Seventy-four participants (47%) were referred to pediatric pulmonary clinic and 25 (34%) of these participants scheduled clinic appointments; however, only 13 (52%) were evaluated in pulmonary clinic. Clinic-based asthma screening and spirometry frequently identified individuals with asthma and pulmonary function abnormalities. Only 22% of those referred were eventually seen in pulmonary clinic. The impact of improved screening and treatment on the pulmonary morbidity in SCD needs to be defined and is an area for future investigation. In addition, case management or multidisciplinary clinics may enhance future screening programs.

Acute Chest Syndrome in Children with Sickle Cell Disease

Acute chest syndrome (ACS) is a frequent cause of acute lung disease in children with sickle cell disease (SCD). Patients may present with ACS or may develop this complication during the course of a hospitalization for acute vaso-occlusive crises (VOC). ACS is associated with prolonged hospitalization, increased risk of respiratory failure, and the potential for developing chronic lung disease. ACS in SCD is defined as the presence of fever and/or new respiratory symptoms accompanied by the presence of a new pulmonary infiltrate on chest X-ray. The spectrum of clinical manifestations can range from mild respiratory illness to acute respiratory distress syndrome. The presence of severe hypoxemia is a useful predictor of severity and outcome. The etiology of ACS is often multifactorial. One of the proposed mechanisms involves increased adhesion of sickle red cells to pulmonary microvasculature in the presence of hypoxia. Other commonly associated etiologies include infection, pulmonary fat embolism, and infarction. Infection is a common cause in children, whereas adults usually present with pain crises. Several risk factors have been identified in children to be associated with increased incidence of ACS. These include younger age, severe SCD genotypes (SS or Sβ⁰ thalassemia), lower fetal hemoglobin concentrations, higher steady-state hemoglobin levels, higher steady-state white blood cell counts, history of asthma, and tobacco smoke exposure. Opiate overdose and resulting hypoventilation can also trigger ACS. Prompt diagnosis and management with intravenous fluids, analgesics, aggressive incentive spirometry, supplemental oxygen or respiratory support, antibiotics, and transfusion therapy, are key to the prevention of clinical deterioration. Bronchodilators should be considered if there is history of asthma or in the presence of acute bronchospasm. Treatment with hydroxyurea should be considered for prevention of recurrent episodes. This review evaluates the etiology, pathophysiology, risk factors, clinical presentation of ACS, and preventive and treatment strategies for effective management of ACS.

Improving Medication Adherence with Two-way Short Message Service Reminders in Sickle Cell Disease and Asthma. A feasibility randomized controlled trial

INTRODUCTION

Sickle cell disease (SCD) is a childhood and adult disease that primarily affects African Americans, characterized by life threatening sequelae mitigated by medications. One-way and two-way short message service (SMS) medication reminders have differing efficacy in chronic diseases. There is limited literature about SMS medication reminders in SCD.

OBJECTIVE

The goal of this study was to test the feasibility, defined by recruitment/acceptance, retention/attrition, and technology utilization, of two-way SMS medication reminders in individuals with SCD with and without asthma.

MATERIALS AND METHODS

Participants were randomly allocated to standard care or reminders. Two-way SMS reminders were automated using Research Electronic Data Capture (REDCap) for hydroxyurea, fluticasone, budesonide and montelukast. Adherence was measured using the Morisky Medication Adherence Scale-8 (MMAS-8). Asthma control was assessed using the Childhood and Adult-Asthma Control Tests (ACT). Participants were enrolled 28 to 60 days with a common termination date.

RESULTS

The recruitment rate was 95% (47/49) and 82.9% completed the study. Among the 47 study participants enrolled, 51.1% were male, 61.7% were adults, median age was 20 (range: 3 to 59), and 98% were African Americans. Of the 26 participants receiving messages, 20% responded on over 95% of the days and usage varied with an average response rate of 33%, ranging from 21% to 46%. Medication adherence scores improved significantly in the intervention group (3.42 before, 5.46 after; p=0.002), but not in the control group (3.90 before, 4.75 after; p=0.080). Childhood-ACT scores improved in the intervention group (19.20 before, 24.25 after). Adult-ACT scores within the intervention arm were unchanged (21.0 before, 22.0 after. ACT scores did not improve significantly.

CONCLUSION

This study demonstrated the feasibility for two-way SMS medication reminders to improve medication adherence in a high-risk population where daily medication adherence is critical to health outcomes and quality of life.

Clinical Features of β-Thalassemia and Sickle Cell Disease

Sickle cell disease (SCD) and β-thalassemia are among the most common inherited diseases, affecting millions of persons globally. It is estimated that 5-7% of the world's population is a carrier of a significant hemoglobin variant. Without early diagnosis followed by initiation of preventative and therapeutic care, both SCD and β-thalassemia result in significant morbidity and early mortality. Despite great strides in the understanding of the molecular basis and pathophysiology of these conditions, the burden of disease remains high, particularly in limited resource settings. Current therapy relies heavily upon the availability and safety of erythrocyte transfusions to treat acute and chronic complications of these conditions, but frequent transfusions results in significant iron overload, as well as challenges from acquired infections and alloimmunization. Hydroxyurea is a highly effective treatment for SCD but less so for β-thalassemia, and does not represent curative therapy. As technology and use of cellular and gene therapies expand, SCD and thalassemia should be among the highest disease priorities.

Secondhand Smoke Is an Important Modifiable Risk Factor in Sickle Cell Disease: A Review of the Current Literature and Areas for Future Research

Sickle cell disease (SCD) is an autosomal recessive hemoglobinopathy that causes significant morbidity and mortality related to chronic hemolytic anemia, vaso-occlusion, and resultant end-organ damage. Tobacco smoke exposure (TSE) through secondhand smoke exposure in people with SCD of all ages and through primary smoking in adolescents and adults is associated with significantly increased morbidity, with increased rates of emergency department visits and hospitalizations for painful vaso-occlusive crises and acute chest syndrome (ACS). Secondhand smoke is also associated with pulmonary function abnormalities in children with SCD who are already at risk for pulmonary function abnormalities on the basis of SCD. TSE is emerging as one of the few modifiable risk factors of SCD. This review discusses the current state of the evidence with respect to TSE and SCD morbidity, discusses potential mechanisms, and highlights current gaps in the evidence and future research directions.

Asthma as a disruption in iron homeostasis

Over several decades, asthma has evolved from being recognized as a single disease to include a diverse group of phenotypes with dissimilar natural histories, pathophysiologies, responses to treatment, and distinctive molecular pathways. With the application of Occam's razor to asthma, it is proposed that there is one cause underlying the numerous phenotypes of this disease and that the responsible molecular pathway is a deficiency of iron in the lung tissues. This deficiency can be either absolute (e.g. asthma in the neonate and during both pregnancy and menstruation) or functional (e.g. asthma associated with infections, smoking, and obesity). Comparable associations between asthma co-morbidity (e.g. eczema, urticaria, restless leg syndrome, and pulmonary hypertension) with iron deficiency support such a shared mechanistic pathway. Therapies directed at asthma demonstrate a capacity to impact iron homeostasis, further strengthening the relationship. Finally, pathophysiologic events producing asthma, including inflammation, increases in Th2 cells, and muscle contraction, can correlate with iron availability. Recognition of a potential association between asthma and an absolute and/or functional iron deficiency suggests specific therapeutic interventions including inhaled iron.

Improved Guideline Adherence With Integrated Sickle Cell Disease and Asthma Care

INTRODUCTION

In children with sickle cell disease (SCD), concomitant asthma is associated with increased morbidity and mortality when compared with children with SCD without asthma. Despite the well-established burden of asthma in children with SCD, no paradigm of care exists for the co-management of these two diseases.

METHODS

To address this gap, an integrated SCD and asthma clinic was created in a community health center that included (1) a dual respiratory therapist/asthma case manager; (2) an SCD nurse practitioner with asthma educator certification; (3) an onsite pulmonary function test laboratory; (4) a pediatric hematologist with expertise in managing SCD and asthma; and (5) application of the National Asthma Education and Prevention Program guidelines. A before (2010-2012) and after (2013-2014) study design was used to assess for improved quality of care with implementation of an integrative care model among 61 children with SCD and asthma followed from 2010 to 2014.

RESULTS

Asthma action plan utilization after initial diagnosis increased with the integrative care model (n=16, 56% before, 100% after, p=0.003), as did the use of spirometry in children aged ≥5 years (n=41, 65% before, 95% after, p<0.001) and correction of lower airway obstruction (n=10, 30% before, 80% after, p=0.03).

CONCLUSIONS

Although the use of an integrative care model for SCD and asthma improved evidence-based asthma care, longer follow-up and evaluation will be needed to determine the impact on SCD-related morbidity.

Sickle cell disease: wheeze or asthma?

Sickle cell disease (SCD) is the most common life-limiting genetic disease among African Americans, affecting more than 100,000 people in the United States. Respiratory disorders in patients with sickle cell disease have been associated with increased morbidity and mortality. Associations between asthma and pain, acute chest syndrome (ACS), and even death have long been reported. More recently wheezing, even in the absence of an asthma diagnosis, has gained attention as a possible marker of SCD severity. Several challenges exist with regards to making the diagnosis of asthma in patients with SCD, including the high prevalence of wheezing, evidence of airway obstruction on pulmonary function testing, and/or airway hyperresponsiveness among patients with SCD. These features often occur in isolation, in the absence of other clinical criteria necessary for an asthma diagnosis. In this review we will summarize: 1) Our current understanding of the epidemiology of asthma, wheezing, airway obstruction, and airway responsiveness among patients with SCD; 2) The evidence supporting associations with SCD morbidity; 3) Our understanding of the pathophysiology of airway inflammation in SCD; 4) Current approaches to diagnosis and management of asthma in SCD; and 5) Future directions.

Application of an Asthma Screening Questionnaire in Children with Sickle Cell Disease

Objective: Asthma in sickle cell disease (SCD) patients is associated with elevated morbidity and mortality. Early detection and initiation of treatment may therefore lead to improved outcome. Utility of an asthma screening questionnaire to identify obstructive airway disease and physician diagnosed asthma in children with SCD at an outpatient setting as an effective, easy-to-administer screening tool has not previously been evaluated in this population. Methods: A previously validated asthma screening questionnaire and spirometry were prospectively administered to 41 SCD children at a routine clinic visit. Results: Prevalence of obstructive airway was 51.2% (n = 21) and physician diagnosis of asthma 33.3% (n = 13). Sensitivity (40%) and specificity (75%) of the questionnaire was poor in detecting obstructive airway disease, but sensitivity (77%), specificity (100%), positive predictive value (100%), and negative predictive value (90%) were high in detecting physician diagnosis of asthma. Conclusion: An asthma screening questionnaire could be a useful tool in identifying at-risk SCD children who may benefit from further management.

Pulmonary function indices in children with sickle cell anemia in Enugu, south-east Nigeria

Objectives:

To determine the pulmonary function indices of children with sickle cell anemia (SCA) attending the pediatric sickle cell clinic at the University of Nigeria Teaching Hospital, Enugu, south-east Nigeria and to compare these indices with the results obtained from other regions.

Methods:

A case control study of lung function in children with SCA aged 6-20 years. The study was carried out in the University of Nigeria/University of Nigeria Teaching Hospital, Enugu State, Nigeria between October 2014 and January 2015. Measurements of the peak expiratory flow rate, forced vital capacity (FVC), and forced expiratory volume in one second (FEV1) were evaluated.

Results:

A total of 80 subjects were recruited into the study, comprising 40 homozygous HbSS (hemoglobin SS) patients and an equal number of controls. Children with SCA had statistically lower values of FEV1 (1.6±0.52), FVC (1.76±0.95), and peak expiratory flow rate (PEFR) (309.00±82.64) when compared with normal hemoglobin genotype FEV1 (12.01±0.53), FVC (2.12±0.54), and PEFR (364.10±87.85). The mean FVC, FEV1/FVC, and PEFR were also higher in the male control group compared with the HbSS male group, but these differences were not statistically significant. Female controls had significantly larger FEV1, FVC, and PEFR values compared with the HbSS females.

Conclusion:

The lung function indices were significantly lower in children and adolescents with SCA compared with the matched controls with a hemoglobin genotype AA.

Increased risk of severe vaso-occlusive episodes after initial acute chest syndrome in children with sickle cell anemia less than 4 years old: Sleep and asthma cohort

Previous studies have shown that the highest incidence of acute chest syndrome (ACS) in sickle cell disease occurs in children <4 years old, and a history of ACS at this age is a risk factor for future ACS episodes. However, the interval associated with the highest risk of subsequent ACS or severe pain is not known. Through this mixed retrospective-prospective observational study, the Sleep and Asthma Cohort, we sought to determine the interval after an initial ACS episode during which the majority of children <4 years old are rehospitalized for ACS or severe pain. The cumulative prevalence of rehospitalization for ACS or severe pain within 6 months, 1 years, and 2 years was calculated for children with an initial ACS episode <4 years old and compared to children with an initial ACS episode ≥4 years old. A total of 44.8% and 55.2% of participants had an initial ACS episode <4 years and ≥4 years old (Range: 4-17.7 years), respectively. At 1 year following the initial ACS episode, children <4 years old had a significantly higher cumulative prevalence of rehospitalizations for ACS or pain as compared to children ≥4 years of age, 62.5 and 39.1%, respectively (P = 0.009). After initial ACS episodes, the majority of children <4 years old will be rehospitalized for ACS or severe pain within one year, suggesting the need for a therapeutic intervention for this high-risk group.

Factors predicting future ACS episodes in children with sickle cell anemia

While a doctor-diagnosis of asthma is associated with an increased risk of pain and acute chest syndrome (ACS) in children with sickle cell anemia (SCA), little is known about the relationship between specific asthma characteristics and clinical factors and future morbidity in children with SCA. We evaluated the relationship between (i) asthma risk factors at the time of a clinical visit (respiratory symptoms, maternal history of asthma, allergy skin tests, spirometry results) and (ii) the known risk factor of ACS early in life, on prospective pain and ACS episodes in a cohort of 159 children with SCA followed from birth to a median of 14.7 years. An ACS episode prior to 4 years of age, (incidence rate ratio [IRR] = 2.84; P < 0.001], female gender (IRR = 1.80; P = 0.009), and wheezing causing shortness of breath (IRR = 1.68; P = 0.042) were associated with future ACS rates. We subsequently added spirometry results (obstruction defined as FEV1 /FVC less than the lower limits of normal; and bronchodilator response, FEV1 ≥ 12%) and prick skin test responses to the model. Only ≥ 2 positive skin tests had a significant effect (IRR 1.87; P = 0.01). Thus, early in life ACS events, wheezing causing shortness of breath, and ≥ 2 positive skin tests predict future ACS events.

Wheezing symptoms and parental asthma are associated with a physician diagnosis of asthma in children with sickle cell anemia

OBJECTIVE

To identify factors associated with asthma associated with increased sickle cell anemia (SCA).

STUDY DESIGN

Children with SCA (N = 187; mean age 9.6 years, 48% male) were classified as having "asthma" based on parent report of physician diagnosis plus prescription of asthma medication (n = 53) or "no asthma" based on the absence of these features (n = 134). Pain and acute chest syndrome (ACS) events were collected prospectively.

RESULTS

Multiple variable logistic regression model identified 3 factors associated with asthma: parent with asthma (P = .006), wheezing causing shortness of breath (P = .001), and wheezing after exercise (P < .001). When ≥2 features were present, model sensitivity was 100%. When none of the features were present, model sensitivity was 0%. When only 1 feature was present, model sensitivity was also 0%, and presence of ≥2 of positive allergy skin tests, airway obstruction on spirometry, and bronchodilator responsiveness did not improve clinical utility. ACS incident rates were significantly higher in individuals with asthma than in those without asthma (incident rate ratio 2.21, CI 1.31-3.76), but pain rates were not (incident rate ratio 1.28, CI 0.78-2.10).

CONCLUSIONS

For children with SCA, having a parent with asthma and specific wheezing symptoms are the best features to distinguish those with and without parent report of a physician diagnosis of asthma and to identify those at higher risk for ACS events. The value of treatment for asthma in the prevention of SCA morbidity needs to be studied.

Wheezing in children with sickle cell disease

PURPOSE OF REVIEW

The purpose of this article is to provide a comprehensive review of wheezing in sickle cell disease (SCD), including epidemiology, pathophysiology, associations between wheezing and SCD morbidity and finally the clinical approach to evaluation and management of individuals with SCD who wheeze.

RECENT FINDINGS

Wheezing is common in SCD and in some individuals represents an intrinsic component of SCD-related lung disease rather than asthma. Emerging data suggest that, regardless of the cause, individuals with SCD and with recurrent wheezing are at increased risk for subsequent morbidity and premature mortality. We believe individuals who acutely wheeze and have respiratory symptoms should be managed with a beta agonist and short-term treatment of oral steroids, typically less than 3 days to attenuate rebound vaso-occlusive disease. For those who wheeze and have a history or examination associated with atopy, we consider asthma treatment and monitoring per National Heart, Lung and Blood Institute asthma guidelines.

SUMMARY

Wheezing in SCD should be treated aggressively both in the acute setting and with controller medications. Prospective SCD-specific clinical trials will be necessary to address whether anti-inflammatory asthma therapies (leukotriene antagonists, inhaled corticosteroids) can safely mitigate the sequelae of wheezing in SCD.

Management of sickle cell disease from childhood through adulthood

Sickle cell disease (SCD) is a genetic disorder characterised by anaemia and "sickling" of red blood cells, leading to chronic haemolytic anaemia, vascular injury, and organ dysfunction. Although children and adults experience many similar symptoms and problems, complications increase with age, leading to early mortality. Hydroxyurea (hydroxycarbamide), the only US Food and Drug Administration-approved treatment, continues to be under-utilised and other treatments available to children are often inaccessible for adults. Haematopoietic stem-cell transplantation is a curative option, but is limited by a lack of donors and concerns for transplant-related toxicities. Although comprehensive programs exist in paediatrics, affected adults may not have access to preventative and comprehensive healthcare because of a lack of providers or care coordination. They are often forced to rely on urgent care, leading to increased healthcare utilisation costs and inappropriate treatment. This problem highlights the importance of primary care during the transition from paediatrics to adulthood.

Clinical correlates of acute pulmonary events in children and adolescents with sickle cell disease

OBJECTIVES

We aimed to identify risk factors for acute pulmonary events in children and adolescents in the Pulmonary Hypertension and the Hypoxic Response in SCD (PUSH) study.

METHODS

Patients with hemoglobin SS (n = 376) and other sickle cell genotypes (n = 127) aged 3-20 yrs were studied at four centers in a cross-sectional manner. A subgroup (n = 293) was followed for a median of 21 months (range 9-35).

RESULTS

A patient-reported history of one or more acute pulmonary events, either acute chest syndrome (ACS) or pneumonia, was obtained in 195 hemoglobin SS patients (52%) and 51 patients with other genotypes (40%). By logistic regression, history of acute pulmonary events was independently associated with patient-reported history of asthma (P < 0.0001), older age (P = 0.001), >3 severe pain episodes in the preceding 12 months (P = 0.002), higher tricuspid regurgitation velocity (TRV) (P = 0.028), and higher white blood cell (WBC) count (P = 0.043) among hemoglobin SS patients. History of acute pulmonary events was associated with >3 severe pain episodes (P = 0.009) among patients with other genotypes. During follow-up, 43 patients (15%) had at least one new ACS episode including 11 without a baseline history of acute pulmonary events. History of acute pulmonary events (odds ratio 5.0; P < 0.0001) and younger age (odds ratio 0.9; P = 0.007) were independently associated with developing a new episode during follow-up.

CONCLUSIONS

Asthma history, frequent pain, and higher values for TRV and WBC count were independently associated with history of acute pulmonary events in hemoglobin SS patients and frequent pain was associated in those with other genotypes. Measures to reduce pain episodes and control asthma may help to decrease the incidence of acute pulmonary events in SCD.

Wheezing and asthma are independent risk factors for increased sickle cell disease morbidity

To assess the associations between a doctor diagnosis of asthma and wheezing (independent of a diagnosis of asthma) with sickle cell disease (SCD) morbidity, we conducted a retrospective review of Emergency Department (ED) visits to the Mount Sinai Medical Center for SCD between 1 January 2007 and 1 January 2011. Outcomes were ED visits for pain and acute chest syndrome. The cohort included 262 individuals, median age 23·8 years, (range: 6 months to 67·5 years). At least one episode of wheezing recorded on a physical examination was present in 18·7% (49 of 262). Asthma and wheezing did not overlap completely, 53·1% of patients with wheezing did not carry a diagnosis of asthma. Wheezing was associated with a 118% increase in ED visits for pain (95% confidence interval [CI]: 56-205%) and a 158% increase in ED visits for acute chest syndrome (95% CI: 11-498%). A diagnosis of asthma was associated with a 44% increase in ED utilization for pain (95% CI: 2-104%) and no increase in ED utilization for acute chest syndrome (rate ratio 1·00, 95%CI 0·41-2·47). In conclusion, asthma and wheezing are independent risk factors for increased painful episodes in individuals with SCD. Only wheezing was associated with more acute chest syndrome.

Risk factors for increased ED utilization in a multinational cohort of children with sickle cell disease

OBJECTIVES

The objective was to identify clinical, social, and environmental risk factors for increased emergency department (ED) use in children with sickle cell disease (SCD).

METHODS

This study was a secondary analysis of ED utilization data from the international multicenter Silent Cerebral Infarct Transfusion (SIT) trial. Between December 2004 and June 2010, baseline demographic, clinical, and laboratory data were collected from children with SCD participating in the trial. The primary outcome was the frequency of ED visits for pain. A secondary outcome was the frequency of ED visits for acute chest syndrome.

RESULTS

The sample included 985 children from the United States, Canada, England, and France, for a total of 2,955 patient-years of data. There were 0.74 ED visits for pain per patient-year. A past medical history of asthma was associated with an increased risk of ED utilization for both pain (rate ratio [RR] = 1.28, 95% confidence interval [CI] = 1.04 to 1.58) and acute chest syndrome (RR = 1.60, 95% CI = 1.03 to 2.49). Exposure to environmental tobacco smoke in the home was associated with 73% more ED visits for acute chest syndrome (RR = 1.73, 95% CI = 1.09 to 2.74). Each $10,000 increase in household income was associated with 5% fewer ED visits for pain (RR = 0.95, 95% CI = 0.91 to 1.00, p = 0.05). The association between low income and ED utilization was not significantly different in the United States versus countries with universal health care (p = 0.51).

CONCLUSIONS

Asthma and exposure to environmental tobacco smoke are potentially modifiable risk factors for greater ED use in children with SCD. Low income is associated with greater ED use for SCD pain in countries with and without universal health care.