Clinical Factors Associated with Morbidity and Mortality in Patients Admitted with Sickle Cell Disease

Impaired hemoglobin clearance by sinusoidal endothelium promotes vaso-occlusion and liver injury in sickle cell disease

Sickle cell disease (SCD) is a monogenic disorder that affects 100,000 African-Americans and millions of people worldwide. Intra-erythrocytic polymerization of sickle hemoglobin (HbS) promotes erythrocyte sickling, impaired rheology, ischemia and hemolysis, leading to the development of progressive liver injury in SCD. Liver-resident macrophages and monocytes are known to enable the clearance of HbS; however, the role of liver sinusoidal endothelial cells (LSEC) in HbS clearance and liver injury in SCD remains unknown. Using real-time intravital (in vivo) imaging in mice liver as well as flow cytometric analysis and confocal imaging of primary human LSEC, we show for the first time that liver injury in SCD is associated with accumulation of HbS and iron in the LSEC, leading to senescence of these cells. Hemoglobin uptake by LSEC was mediated by micropinocytosis. Hepatic monocytes were observed to attenuate LSEC senescence by accelerating HbS clearance in the liver of SCD mice; however, this protection was impaired in P-selectin-deficient SCD mice secondary to reduced monocyte recruitment in the liver. These findings are the first to suggest that LSEC contribute to HbS clearance and HbS-induced LSEC senescence promotes progressive liver injury in SCD mice. Our results provide a novel insight into the pathogenesis of hemolysis-induced chronic liver injury in SCD caused by LSEC senescence. Identifying the regulators of LSEC-mediated HbS clearance may lead to new therapies to prevent the progression of liver injury in SCD.

Coronavirus disease 2019 (COVID-19) in special groups: A single-center experience in sickle cell disease patients in Saudi Arabia

BACKGROUND

Sickle cell disease (SCD) is a group of hereditary diseases, inherited as autosomal recessive disorder, which causes mutation in the β-globin gene. As a result, there is a change in the sixth amino acid from glutamic acid to valine. The affected red blood cell is then prone to polymerization and sickling crisis under conditions of low oxygen tension. One of the major causes of mortality in SCD is acute chest syndrome (ACS). On the other hand, coronavirus disease 2019 (COVID-19) is a pandemic disease that carries significant mortality and morbidity worldwide with unknown outcomes in the affected SCD population. This study was created for that reason.

MATERIALS AND METHODS

We report a case series of ten SCD patients who were affected by COVID-19 and required admission between May 1, 2020, and October 30, 2020, at a tertiary care hospital in Dhahran, eastern region of Saudi Arabia. Historical data were obtained retrospectively from electronic records. MS Excel was used for data entry, and SPSS version 23 was used for data analysis.

RESULTS

The mean age of the patients involved in the study was 32 years, and the mean duration of symptoms was 5.7 days. None required critical care admission, and there was no mortality. All patients were discharged from hospital in good condition with no requirement of home oxygen.

CONCLUSION

Although we expected a fatal outcome of SCD patients affected by COVID-19 infection, our limited case series showed favorable disease behavior and outcome, with a suspicion of underlying unclear protective mechanism from serious complications. However, further studies are required to better understand COVID-19 behavior in SCD patients.

Comparison of the clinical course of COVID-19 infection in sickle cell disease patients with healthcare professionals

It is highly expected that COVID-19 infection will have devastating consequences in sickle cell disease (SCD) patients due to endothelial activation and decreased tissue and organ reserve as a result of microvascular ischemia and continuous inflammation. In this study, we aimed to compare the clinical course of COVID-19 in adult SCD patients under the organ injury mitigation and clinical care improvement program (BASCARE) with healthcare professionals without significant comorbid conditions. The study was planned as a retrospective, multicenter and cross-sectional study. Thirty-nine SCD patients, ages 18 to 64 years, and 121 healthcare professionals, ages 21 to 53, were included in the study. The data were collected from the Electronic Health Recording System of PRANA, where SCD patients under the BASCARE program had been registered. The data of other patients were collected from the Electronic Hospital Data Recording System and patient files. In the SCD group, the crude incidence of COVID-19 was 9%, while in healthcare professionals at the same period was 23%. Among the symptoms, besides fever, loss of smell and taste were more prominent in the SCD group than in healthcare professionals. There was a significant difference between the two groups in terms of development of pneumonia, hospitalization, and need for intubation (43 vs 5%, P < 0.00001; 26 vs 7%, P = 0.002; and 10 vs 1%, P = 0.002, respectively). Prophylactic low molecular weight heparin and salicylate were used more in the SCD group than in healthcare professionals group (41 vs 9% and 28 vs 1%; P < 0.0001 for both). The 3-month mortality rate was demonstrated as 5% in the SCD group, while 0 in the healthcare professionals group. One patient in the SCD group became continously dependent on respiratory support. The cause of death was acute chest syndrome in the first case, hepatic necrosis and multi-organ failure in the second case. In conclusion, these observations supported the expectation that the course of COVID-19 in SCD patients will get worse. The BASCARE program applied in SCD patients could not change the poor outcome.

All-Cause Mortality and Incidence of Major Adverse Cardiac Events in Sickle Cell Nephropathy: A Comparative Study

Background

Sickle cell disease (SCD) is an autosomal recessive disease resulting in hemolytic anemia and recurrent vaso-occlusive events. Consequently, it can result in a broad range of functional and structural renal and cardiac alterations. Chronic kidney disease (CKD), in SCD, is associated with proteinuria, microalbuminuria, and hemoglobinuria. Cardiac complications in SCD include pulmonary hypertension, left ventricular diastolic heart disease, dysrhythmia, and sudden death. In patients with advancing age, cardio-renal dysfunction can have substantial effects on morbidity and mortality. Our primary aim was to compare the incidence of major adverse cardiac events (MACE) and all-cause mortality in sickle cell nephropathy (SCN).

Methods

In this retrospective study, we used International Classification of Diseases (ICD)-10 codes to identify admissions in 2019 with a diagnosis of MACE with a prior diagnosis of SCD and/or SCN. Our search of the HCA Healthcare Enterprise Data Warehouse for adult patients >18 years yielded 6,693 patients with SCD, of which 658 patients (9.8%) had SCN. Primary endpoints were incidence of MACE and all-cause mortality. Patients with MACE encompassed those with nonfatal stroke, nonfatal myocardial infarction, and congestive heart failure (CHF) exacerbations. A secondary endpoint was length of stay (LOS). Logistic regression analysis was used for MACE and all-cause mortality. LOS was analyzed using multiple linear regression analysis. Results were considered statistically significant for analyses showing p <0.05. All outcomes were adjusted for demographic variables and comorbidities.

Results

Logistic regression, after adjustment for comorbidities, demonstrated that SCN patients had significantly higher odds of all-cause mortality (odds ratio [OR] 2.343, p = 0.035, 95% confidence interval [CI] 1.063-5.166) compared to patients without SCN. Compared to those without SCN, those with SCN did not have a higher odds of MACE (OR 1.281, p = 0.265, 95% CI 0.828-1.982). Linear regression for LOS did not reveal a significant association with SCN (p = 0.169, 95% CI 0.157-0.899).

Conclusion

Based on the analysis of 6,693 patients with SCD, SCN was associated with significantly higher odds of all-cause mortality. SCN was not associated with significantly higher odds of MACE or prolonged LOS.

Emergency department utilization for sickle cell disease in St. Vincent and the Grenadines

Introduction

sickle cell disease (SCD) is a chronic illness. Individuals affected by this disease are at risk for lifelong complications including episodes of acute pain, chronic pain and multi-organ injury that leads to reduced quality of life and a shortened life span. There is a wealth of data on acute care utilization for SCD in the United States. However, data from the Caribbean region is limited. The objective of this study is to explore Emergency Department (ED) utilization for SCD in St. Vincent and the Grenadines by describing: i) the characteristics of SCD related ED encounters; ii) the urgency of these encounters as defined by resource utilization; iii) the disposition for these ED encounters.

Methods

the study was a cross-sectional study utilizing data from the ED log books at the Milton Cato Memorial Hospital (MCMH) during non-consecutive time periods between January 1^st, 2012 - December 31^st, 2016.

Results

there were 666 SCD-related ED encounters during the study period. Thirty-four percent of encounters resulted in hospitalization and 66% of encounters met criteria for an urgent visit. The most commonly reported diagnosis was vaso-occlusive crisis and accounted for 84% of all encounters. The most frequently documented age group was the 18-30 age category at 43%.

Conclusion

although SCD comprised less than 2% of all ED visits, the majority of these visits could be classified as urgent visits based on resource utilization. This study adds to the emerging data on the burden of this disease in this St. Vincent and the Grenadines.

Impaired Bile Secretion Promotes Hepatobiliary Injury in Sickle Cell Disease

BACKGROUND AND AIMS

Hepatic crisis is an emergent complication affecting patients with sickle cell disease (SCD); however, the molecular mechanism of sickle cell hepatobiliary injury remains poorly understood. Using the knock-in humanized mouse model of SCD and SCD patient blood, we sought to mechanistically characterize SCD-associated hepato-pathophysiology applying our recently developed quantitative liver intravital imaging, RNA sequence analysis, and biochemical approaches.

APPROACH AND RESULTS

SCD mice manifested sinusoidal ischemia, progressive hepatomegaly, liver injury, hyperbilirubinemia, and increased ductular reaction under basal conditions. Nuclear factor kappa B (NF-κB) activation in the liver of SCD mice inhibited farnesoid X receptor (FXR) signaling and its downstream targets, leading to loss of canalicular bile transport and altered bile acid pool. Intravital imaging revealed impaired bile secretion into the bile canaliculi, which was secondary to loss of canalicular bile transport and bile acid metabolism, leading to intrahepatic bile accumulation in SCD mouse liver. Blocking NF-κB activation rescued FXR signaling and partially ameliorated liver injury and sinusoidal ischemia in SCD mice.

CONCLUSIONS

These findings identify that NF-κB/FXR-dependent impaired bile secretion promotes intrahepatic bile accumulation, which contributes to hepatobiliary injury of SCD. Improved understanding of these processes could potentially benefit the development of therapies to treat sickle cell hepatic crisis.

Renal Failure in Sickle Cell Disease: Prevalence, Predictors of Disease, Mortality and Effect on Length of Hospital Stay

Renal dysfunction in sickle cell disease is not only a chronic comorbidity but also a mortality risk factor. Though renal dysfunction starts early in life in sickle cell patients, the predictors that can identify sickle cell disease patients at risk of developing renal dysfunction is not known. We used the Truven Health MarketScan^® Medicaid Databases from 2007 to 2012. Incidence of new acute renal failure (ARF) and chronic kidney disease (CKD) was calculated in this cohort. There were 9481 patients with a diagnosis of sickle cell disease accounting for 64,201 hospital admissions, during the study period. Both ARF and CKD were associated with higher risk of inpatient mortality, longer duration of the hospital stay and expensive hospitalizations. The yearly incidence of new ARF in sickle cell disease patients was 1.4% and annual CKD incidence was 1.3%. The annual rate of new ARF and CKD in the control group was 0.4 and 0.6%, respectively. The most important predictors of new CKD were proteinuria, ARF and hypertension. Chronic kidney disease, hypertension and sickle cell crisis were the most important predictors of new ARF. The annual rate of incidences of ARF and CKD were 2- to 3-fold higher in sickle cell disease compared to the non sickle cell disease group. Besides the common risk factors for renal disease in the general population, it is imperative to monitor the sickle cell disease patients with more severe disease to prevent them from developing renal dysfunction.