The publication data currently available has been vetted by Vanderbilt faculty, staff, administrators and trainees. The data itself is retrieved directly from NCBI's PubMed and is automatically updated on a weekly basis to ensure accuracy and completeness.
If you have any questions or comments, please contact us.
Sickle cell disease (SCD) is associated with adverse pregnancy outcome. In women with SCD living in low-resource settings, pregnancy is associated with significantly increased maternal and perinatal mortality rates. We tested the hypothesis that implementing a multidisciplinary obstetric and hematology care team in a low-resource setting would significantly reduce maternal and perinatal mortality rates. We conducted a before-and-after study, at the Korle-Bu Teaching Hospital in Accra, Ghana, to evaluate the effect of a multidisciplinary obstetric-hematology care team for women with SCD in a combined SCD-Obstetric Clinic. The pre-intervention period was assessed through a retrospective chart review to identify every death and the post-intervention period was assessed prospectively. Interventions consisted of joint obstetrician and hematologist outpatient and acute inpatient reviews, close maternal and fetal surveillance, and simple protocols for management of acute chest syndrome and acute pain episodes. Primary outcomes included maternal and perinatal mortality rates before and after the study period. A total of 158 and 90 pregnant women with SCD were evaluated in the pre- and post- intervention periods, respectively. The maternal mortality rate decreased from 10 791 per 100 000 live births at pre-intervention to 1176 per 100 000 at post-intervention, representing a risk reduction of 89.1% (P = 0.007). Perinatal mortality decreased from 60.8 per 1000 total births at pre-intervention to 23.0 per 1000 at post-intervention, representing a risk reduction of 62.2% (P = 0.20). A multidisciplinary obstetric and hematology team approach can dramatically reduce maternal and perinatal mortality in a low-resource setting.
© 2017 Wiley Periodicals, Inc.
Current definitions of acute chest syndrome (ACS) in sickle cell anemia (SCA) do not account for rapid progression of respiratory compromise. In this two-center retrospective cohort study, we tested the hypothesis that in children and adults with ACS and respiratory failure (≤24 hours after onset of respiratory symptoms) have a distinct ACS phenotype associated with multiorgan failure when compared to those with ACS that have a more subacute and protracted course. We identified 173 individuals (97 children <20 years and 76 adults ≥20 years) with SCA and at least one episode of ACS. Only one ACS episode was considered per individual. Rapidly progressive ACS occurred in 21% (n = 16) of adults, but only 2.1% (n = 2) of children. Compared to adults without rapidly progressive ACS, adults with rapidly progressive ACS more frequently developed acute kidney injury (68.8% vs. 3.3%, P < 0.001), hepatic dysfunction (75.0% vs. 15.0%, P < 0.001), altered mental status (43.8% vs. 11.7%, P < 0.001), multiorgan failure (93.8% vs. 10%, P < 0.001), and death (6.3% vs. 0%, P = 0.05). Clinical and laboratory covariates that were evaluable on the first day of respiratory symptoms were evaluated to identify predictors of rapidly progressive ACS. On multivariable analysis, decline in platelet count at presentation was the only predictor of rapidly progressive ACS [odds ratio 4.82 (95% CI 1.20-19.39), P = 0.027]. In conclusion, rapidly progressive ACS is a distinct phenotype that occurs more frequently in adults, is preceded by thrombocytopenia, and is associated with multiorgan failure. Am. J. Hematol. 91:1185-1190, 2016. © 2016 Wiley Periodicals, Inc.
© 2016 Wiley Periodicals, Inc.
Acute chest syndrome is a frequent cause of acute lung disease in children with sickle-cell disease. Asthma is common in children with sickle-cell disease and is associated with increased incidence of vaso-occlusive pain events, acute chest syndrome episodes, and earlier death. Risk factors for asthma exacerbation and an acute chest syndrome episode are similar, and both can present with shortness of breath, chest pain, cough, and wheezing. Despite overlapping risk factors and symptoms, an acute exacerbation of asthma or an episode of acute chest syndrome are two distinct entities that need disease-specific management strategies. Although understanding has increased about asthma as a comorbidity in sickle-cell disease and its effects on morbidity, substantial gaps remain in knowledge about best management.
Copyright © 2016 Elsevier Ltd. All rights reserved.
RATIONALE - Patient factors associated with development of abnormal lung function in children with sickle cell anemia (SCA) have not been fully characterized.
OBJECTIVES - To characterize lung function abnormalities among children with SCA and to determine whether these steady-state lung function results were associated with morbidity before or after testing among children with SCA.
METHODS - This study was part of the prospective National Institutes of Health-funded Sleep and Asthma Cohort Study. Children with HbSS or Hb Sβ(o) (SCA) were enrolled without regard for sickle cell-related comorbidities or diagnosis of asthma. Lung function was measured by spirometry and plethysmography on the same day, when free of acute disease. Standardized asthma symptom questionnaires and review of the medical records were also performed.
MEASUREMENTS AND MAIN RESULTS - A total of 149 children aged 6 to 19 years completed lung function testing, of whom 139 participants had retrospective morbidity data from birth to the test date, and 136 participants were followed prospectively for a median of 4.3 years from the test date. At baseline, percentages with normal, obstructive, restrictive, nonspecific, and mixed lung function patterns were 70, 16, 7, 6, and 1, respectively. Neither retrospective rates of pain nor acute chest syndrome was associated with lung function patterns. Furthermore, baseline lung function pattern was not predictive of future pain or acute chest syndrome episodes.
CONCLUSIONS - The majority of children with SCA have lung function that is within the normal range. Abnormal lung function patterns were not associated with prior vasoocclusive pain or acute chest syndrome episodes, and baseline lung function patterns did not predict future vasoocclusive pain or chest syndrome episodes.
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.
© 2015 Wiley Periodicals, Inc.
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.
© 2014 Wiley Periodicals, Inc.
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.
Copyright © 2014 Mosby, Inc. All rights reserved.
Genetic diversity at the human β-globin locus has been implicated as a modifier of sickle cell anaemia (SCA) severity. However, haplotypes defined by restriction fragment length polymorphism sites across the β-globin locus have not been consistently associated with clinical phenotypes. To define the genetic structure at the β-globin locus more thoroughly, we performed high-density single nucleotide polymorphism (SNP) mapping in 820 children who were homozygous for the sickle cell mutation (HbSS). Genotyping results revealed very high linkage disequilibrium across a large region spanning the locus control region and the HBB (β-globin gene) cluster. We identified three predominant haplotypes accounting for 96% of the β(S) -carrying chromosomes in this population that could be distinguished using a minimal set of common SNPs. Consistent with previous studies, fetal haemoglobin level was significantly associated with β(S) -haplotypes. After controlling for covariates, an association was detected between haplotype and rate of hospitalization for acute chest syndrome (ACS) (incidence rate ratio 0·51, 95% confidence interval 0·29-0·89) but not incidence rate of vaso-occlusive pain or presence of silent cerebral infarct (SCI). Our results suggest that these SNP-defined β(S) -haplotypes may be associated with ACS, but not pain or SCI in a study population of children with SCA.
© 2013 John Wiley & Sons Ltd.
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.
© 2012 Blackwell Publishing Ltd.
Sickle cell disease is a common hemolytic disorder with a broad range of complications, including vaso-occlusive episodes, acute chest syndrome (ACS), pain, and stroke. Heme oxygenase-1 (gene HMOX1; protein HO-1) is the inducible, rate-limiting enzyme in the catabolism of heme and might attenuate the severity of outcomes from vaso-occlusive and hemolytic crises. A (GT)(n) dinucleotide repeat located in the promoter region of the HMOX1 gene is highly polymorphic, with long repeat lengths linked to decreased activity and inducibility. We examined this polymorphism to test the hypothesis that short alleles are associated with a decreased risk of adverse outcomes (hospitalization for pain or ACS) among a cohort of 942 children with sickle cell disease. Allele lengths varied from 13 to 45 repeats and showed a trimodal distribution. Compared with children with longer allele lengths, children with 2 shorter alleles (4%; ≤ 25 repeats) had lower rates of hospitalization for ACS (incidence rate ratio 0.28, 95% confidence interval, 0.10-0.81), after adjusting for sex, age, asthma, percentage of fetal hemoglobin, and α-globin gene deletion. No relationship was identified between allele lengths and pain rate. We provide evidence that genetic variation in HMOX1 is associated with decreased rates of hospitalization for ACS, but not pain. This study is registered at www.clinicaltrials.gov as #NCT00072761.