Revisiting anemia in sickle cell disease and finding the balance with therapeutic approaches

How I treat anemia in older adults

ABSTRACT

With the global growing older adult population, clinicians face the common, yet complex challenge of how to evaluate and manage anemia in this population. Older age predisposes to common causes of anemia such as nutritional deficiencies, inflammatory disorders, chronic kidney disease, and hematologic malignancies. Failure to diagnose and appropriately manage anemia may result in decreased quality of life, impaired cognition, impaired mobility, and increased mortality. Anemia diagnosis in older adults presents a diagnostic conundrum because anemia may have a single cause, may be multifactorial, or may have no apparent cause even after an extensive evaluation. We believe a systematic approach to diagnosis ensures appropriate testing and avoids the pitfall of undertreatment and overtreatment. In this article we present our recommended approach through common scenarios for the management of anemia in the older adult.

Pyruvate kinase activators: targeting red cell metabolism in sickle cell disease

Hemoglobin S (HbS) polymerization, red blood cell (RBC) sickling, chronic anemia, and vaso-occlusion are core to sickle cell disease (SCD) pathophysiology. Pyruvate kinase (PK) activators are a novel class of drugs that target RBC metabolism by reducing the buildup of the glycolytic intermediate 2,3-diphosphoglycerate (2,3-DPG) and increasing production of adenosine triphosphate (ATP). Lower 2,3-DPG level is associated with an increase in oxygen affinity and reduction in HbS polymerization, while increased RBC ATP may improve RBC membrane integrity and survival. There are currently 3 PK activators in clinical development for SCD: mitapivat (AG-348), etavopivat (FT-4202), and the second-generation molecule AG-946. Preclinical and clinical data from these 3 molecules demonstrate the ability of PK activators to lower 2,3-DPG levels and increase ATP levels in animal models and patients with SCD, as well as influence a number of potential pathways in SCD, including hemoglobin oxygen affinity, RBC sickling, RBC deformability, RBC hydration, inflammation, oxidative stress, hypercoagulability, and adhesion. Furthermore, early-phase clinical trials of mitapivat and etavopivat have demonstrated the safety and tolerability of PK activators in patients with SCD, and phase 2/3 trials for both drugs are ongoing. Additional considerations for this novel therapeutic approach include the balance between increasing hemoglobin oxygen affinity and tissue oxygen delivery, the cost and accessibility of these drugs, and the potential of multimodal therapy with existing and novel therapies targeting different disease mechanisms in SCD.

Le globule rouge drépanocytaire. Données génétiques et structurelles

Sickle cell disease is syndromic, associating a hemolytic anemia, a vaso-obstructive vascular disease, and an infectious risk linked to the precocity of the splenic function loss. The willingly hyperacute and potentially fatal character of the two last elements of the pathophysiologic syndrome, has, quite rightly, focused the therapeutic researches on them. Great success in those two domains have allowed a very important gain in life expectancy. However, chronic progressive organ dysfunction began to appear in older than 25 years-old patients. It concerns mainly renal, hepatic, cardiac functions and pulmonary arterial pressure and may lead to organ failure and premature death. Since some 25 years, the clinical research demonstrated an association between such complications and intravascular hemolytic rate, and it turned to a causative relationship. This present paper try to summarize the actual knowledge on the structural and genetic aspects of sickle cell anemia hemolysis. © 2023 Société nationale française de médecine interne (SNFMI). Published by Elsevier Masson SAS. All rights reserved.

Management of Older Adults with Sickle Cell Disease: Considerations for Current and Emerging Therapies

People with sickle cell disease (SCD) are living longer than ever before, with the median survival increasing from age 14 years in 1973, beyond age 40 years in the 1990s, and as high as 61 years in recent cohorts from academic centers. Improvements in survival have been attributed to initiatives, such as newborn screening, penicillin prophylaxis, vaccination against encapsulated organisms, better detection and treatment of splenic sequestration, and improved transfusion support. There are an estimated 100,000 people living with SCD in the United States and millions of people with SCD globally. Given that the number of older adults with SCD will likely continue to increase as survival improves, better evidence on how to manage this population is needed. When managing older adults with SCD (defined herein as age ≥ 40 years), healthcare providers should consider the potential pitfalls of extrapolating evidence from existing studies on current and emerging therapies that have typically been conducted with participants at mean ages far below 40 years. Older adults with SCD have historically had little to no representation in clinical trials; therefore, more guidance is needed on how to use current and emerging therapies in this population. This article summarizes the available evidence for managing older adults with SCD and discusses potential challenges to using approved and emerging drugs in this population.

Severe Maternal Morbidity and Mortality in Sickle Cell Disease in the National Inpatient Sample, 2012-2018

IMPORTANCE

Pregnancy outcomes are historically poor among people with sickle cell disease (SCD) in the US, most of whom have Black race. Whether outcomes have improved is unknown.

OBJECTIVE

To tabulate adverse pregnancy outcomes among patients with SCD, comparing outcomes of deliveries among Black people with SCD with those of Black people without SCD and a control non-Black population, and to measure the association of racial disparities with adverse outcomes in SCD pregnancies.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study was a secondary analysis involving data from National Inpatient Sample, a nationally representative sample of 20% of acute hospital admissions in the US, between 2012 and 2018. The data set included all admissions with codes for delivery of a pregnancy among people aged 11 to 55 years. Data were analyzed from September 2021 to August 2022.

EXPOSURES

SCD, racial disparities.

MAIN OUTCOMES AND MEASURES

Severe maternal morbidity (SMM) as measured by the US Centers for Disease Control and Prevention's index alongside other outcomes; multiple logistic regression was used to compare the odds for adverse pregnancy outcomes.

RESULTS

The sample included 5 401 899 deliveries, including 3901 deliveries among people with SCD and 742 164 deliveries among people with Black race. Compared with the non-Black control group, patients with SCD and Black patients were younger (mean [SD] age: SCD, 27.2 [5.9] years; Black, 27.1 [6.1] years vs 28.7 [5.9] years) and more likely to have public insurance (SCD, 2609 deliveries [67.3%]; Black, 496 828 deliveries [65.4%] vs 1 880 198 deliveries [40.8%]). The maternal mortality rate in deliveries among people with SCD was 26 times greater than in the non-Black control group and more than 10 times greater than among Black pregnant people without SCD (Per 10 000 deliveries: SCD 13.3; 95% CI, 5.7-31.2; Black race, 1.2; 95% CI, 1.0-1.5; non-Black control 0.5; 95% CI, 0.5-0.6). Compared with the control group, SCD deliveries had higher odds of SMM (adjusted odds ratio [aOR], 7.22; 95% CI, 6.25-8.34; P < .001), especially cerebrovascular events (aOR, 22.00; 95% CI, 15.25-31.72; P < .001) and thromboembolism (aOR, 17.34; 95% CI, 11.55-26.03; P < .001). Racial disparities explained a median (IQR) 28.9% (21.2%-33.1%) of the increased risk in deliveries to people with SCD and between 40% and 50% of the increased risk for acute kidney failure (excess risk [ER], 56.9%; 95% CI, 54.3%-59.3%), intrauterine fetal demise (ER, 47.8%; 95% CI, 46.6%-49.1%), and eclampsia (ER, 42.1%; 95% CI, 37.9%-46.1%).

CONCLUSIONS AND RELEVANCE

In this large cross-sectional study of pregnancy outcomes in people with SCD, the risk for SMM was higher compared with deliveries among people without SCD, especially for thrombotic events, organ failure, and death. Racial disparities were associated with adverse outcomes. Our findings compel scientific, clinical, and political effort to improve outcomes for pregnant people with SCD.

Comparisons of Severe Maternal Morbidity and Other Adverse Pregnancy Outcomes in Pregnant People With Sickle Cell Disease vs Anemia

IMPORTANCE

Pregnancy in sickle cell disease (SCD) is high risk, but whether prenatal anemia, which is treatable with red blood cell transfusions, is a mediator associated with adverse pregnancy outcomes (APOs) is not known.

OBJECTIVE

To compare rates and odds of severe maternal morbidity (SMM) and other APOs in pregnancies among individuals with SCD vs those without SCD but with prenatal anemia.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study was conducted using data from 2012 to 2018 from the National Inpatient Sample, a nationally representative sample of 20% of acute hospital admissions in the United States. All admissions with codes for delivery of a pregnancy among people aged 11 to 55 years were included. Only admissions coded with Black race were included. Data were analyzed from September 2021 through August 2022.

EXPOSURES

Prenatal anemia and SCD.

MAIN OUTCOMES AND MEASURES

SMM was tabulated per the Center for Disease Control and Prevention SMM Index alongside other APOs. Multiple logistic regression was used to compare the odds for APOs and risk ratios (RRs) to compare rates of APOs.

RESULTS

Among 764 455 total delivery admissions among patients identified as Black (mean [SD] age at delivery, 27.00 [6.08] years), 3200 deliveries were coded with maternal SCD, 34 808 deliveries were coded with maternal anemia, and 726 447 deliveries were control. Most patients were publicly insured (499 060 [65.4%]). For most outcomes, including SMM and mortality per 10 000 deliveries, the SCD group had higher rates (SMM: 5.9%; 95% CI, 5.1%-6.8%; maternal mortality: 13.0 deaths; 95% CI, 4.9 to 35.0 deaths) than anemia (SMM: 2.1%; 95% CI, 2.0%-2.3%; maternal mortality: 0.9 deaths; 95% CI, 0.3 to 2.8 deaths) or control groups (SMM: 1.1%; 95% CI, 1.0%-1.1%; maternal mortality: 1.2 deaths; 95% CI, 1.0 to 1.5 deaths). SCD (adjusted odds ratio [aOR], 5.51; 95% CI, 4.71-6.45) and anemia groups (aOR, 2.00; 95% CI, 1.84-2.17) had higher adjusted odds of SMM compared with the control group. However, for many complications associated with ischemia or abnormal placentation, CIs of aORs for SCD and anemia groups overlapped (eg, eclampsia: aOR, 2.74; 95% CI, 1.51-4.96 vs aOR, 1.40; 95% CI, 1.08-1.81). For these complications, RRs for SCD vs anemia were between 1.0 and 2.1 (eg, eclampsia: 1.76; 95% CI, 0.93-3.32). For complications associated with thrombosis or SCD-specific pathologies, rates and aORs were greater for the SCD vs anemia group. For these complications, RRs were between 3.70 and 10.90. For example, rates of acute respiratory distress syndrome, including acute chest syndrome, were 56 of 3144 deliveries (1.8%) vs 122 of 34 686 deliveries (0.4%), and the RR was 4.99 (95% CI, 3.65-6.84).

CONCLUSIONS AND RELEVANCE

This study found that risks associated with prenatal anemia and SCD were similar for many APOs, especially those associated with ischemia and abnormal placentation, suggesting that prenatal anemia may be a mediator associated with pregnancy risk in individuals with SCD.

Hemoglobin and End-Organ Damage in Individuals with Sickle Cell Disease

Background

Sickle cell disease (SCD) is an inherited, chronic, multifaceted blood disorder. Patients with SCD develop anemia, which has been associated with end-organ damage (EOD).

Objectives

This retrospective, observational, repeated-measures study systematically characterizes the relationship between hemoglobin (Hb) level and EOD in adolescent and adult patients with SCD.

Methods

The study population comprised patients with SCD aged ≥12 years with available Hb data from a US provider-centric health care database. For each patient, each Hb value over time was included as a separate observation. Study outcomes-the onset of any new EOD, including chronic kidney disease, pulmonary hypertension, stroke, and leg ulcer-were ascertained during the 1-year period after each Hb assessment. The association between Hb levels and risk of new EOD was estimated using multivariable generalized estimating equations.

Results

A total of 16,043 unique patients with SCD contributed 44,913 observations. Adjusted odds of any EOD during the 1-year follow-up were significantly lower with higher Hb level. Risk reductions with higher Hb levels for chronic kidney disease, pulmonary hypertension, and leg ulcer were comparable. The risk of new EOD was significantly lower among adolescent and adult patients with higher Hb levels.

Conclusions

In patients with SCD, higher Hb levels are associated with a reduced risk of developing EOD. Therapeutic strategies that result in higher Hb levels may offer clinical and economic value for patients with SCD. (Curr Ther Res Clin Exp. 2023; 84:XXX-XXX).

Numb Chin Syndrome in Sickle Cell Disease: A Systematic Review and Recommendations for Investigation and Management

Numb chin syndrome (NCS) is a rare sensory neuropathy resulting from inferior alveolar or mental nerve injury. It manifests as hypoesthesia, paraesthesia, or, rarely, as pain in the chin and lower lip. Several case reports suggest that sickle cell disease (SCD) could be a cause of NCS. However, information about NCS is scarce in this population. Our objectives were to synthesize all the available literature relevant to NCS in SCD and to propose recommendations for diagnosis and management based on the best available evidence. A systematic review was performed on several databases to identify all relevant publications on NCS in adults and children with SCD. We identified 73 publications; fourteen reports met the inclusion/exclusion criteria. These described 33 unique patients. Most episodes of NCS occurred in the context of typical veno-occlusive crises that involved the mandibular area. Radiological signs of bone infarction were found on some imaging, but not all. Neuropathy management was mostly directed toward the underlying cause. Overall, these observations suggest that vaso-occlusion and bone infarction could be important pathophysiological mechanisms of NCS. However, depending on the individual context, we recommend a careful evaluation to rule out differential causes, including infections, local tumors, metastatic disease, and stroke.