Affecting more than 20 million people globally and 100,000 people nationwide, SCD is the most common inherited blood disorder in the United States. It occurs largely but not exclusively among people of African descent.
Patients with SCD develop crescent-shaped or “sickled” red blood cells that, unlike normally round cells, can potentially block blood flow and thus cause a host of problems ranging from a risk of stroke or infections to sometimes severe pain crises, called vaso-occlusive episodes.
To help ward off such complications, some key preventative measures and an array of therapies have become available in recent years: Newborn screening and prophylaxis, including the introduction of pneumococcal vaccines, have substantially reduced rates of invasive pneumococcal infection, which previously accounted for 32% of all causes of death in patients with SCD under the age of 20.
And while hydroxyurea was the only medication from 1998 to 2017 to alleviate acute pain episodes in SCD, newer options have become available in recent years, with l-glutamine, voxelotor, and crizanlizumab gaining FDA approval to further help prevent the episodes.
However, studies show that many if not most patients fail to receive adequate treatment, with one recent report indicating that, between 2016 and 2020, hydroxyurea was prescribed to fewer than 25% of patients with SCD, and fewer than 4% of people with the disease who experience chronic pain episodes had prescriptions for the newer FDA-approved drugs.
Myths and truths
To help clarify some common misconceptions that contribute to the problems, Lewis Hsu, MD, PhD, chief medical officer of the Sickle Cell Disease Association of America, detailed some of the most prevalent and persistent myths among clinicians about SCD:
Dr. Lewis Hsu
courtesy University of Illinois
Pain level
Myths: Firstly, that sickle cell pain is not that bad, and patients therefore don’t really need opioid pain treatment, and secondly, that sickle cell pain is measurable by lab tests, such as the number of sickled red blood cells on a blood smear, reticulocytes, or hemoglobin level.
Truths: “Sickle cell vaso-occlusive pain can be very severe – a 10 on a scale of 10 – but the pain is usually only known by subjective report,” said Dr. Hsu, a pediatric hematologist who serves as director of the Sickle Cell Center and professor of pediatrics for the University of Illinois at Chicago.
“No lab test can be used to measure pain,” he said. “Other lab tests can be abnormal, and some have statistical correlation with lifetime severity of disease course, but the lab tests are not for determination of acute level of pain or absence of pain.”
Blacks only
Myth: SCD only affects Black people.
Truth: People who have sickle cell disease from many ethnic backgrounds and skin colors.
“Around the Mediterranean, there are sickle cell patients from Greece, Turkey, Italy, and Spain. Some are blond and blue-eyed. People in India and Pakistan have sickle cell disease,” Dr. Hsu explained.
In addition, “people from the Arabian Peninsula have sickle cell disease; some Malaysians have sickle cell disease; one child who is about third generation in Hong Kong has sickle cell disease.”
Parental link
Myth: Sickle cell disease only occurs in individuals both of whose parents have the sickle gene.
Truth: “There are types of sickle cell disease [involving] a sickle cell gene from one parent and a gene for hemoglobin C from the other parent,” Dr. Hsu noted. “Others inherited one sickle gene [from one parent] and inherited from the other parent a gene for beta thalassemia. Others involve an inherited sickle gene and hemoglobin E; others have inherited one sickle gene and inherited a gene for hemoglobin D-Punjab, while others have sickle and hemoglobin O-Arab.”
Effects beyond pain
Myth: A person who is not having sickle cell pain is otherwise not significantly affected by their disease.
Truth: “Organs can be damaged silently every day,” Dr. Hsu said. “Kidney failure, retina damage, and pulmonary hypertension are the most notable of organ systems that can suffer damage for a long time without symptoms, then develop symptoms when it is too late to intervene.”
“For this reason, individuals with sickle cell disease should have regular expert care for health maintenance that is disease specific,” Dr. Hsu added.
Consult guidelines
One final concern is a basic failure to utilize critical information sources and guidelines, especially by primary care providers and/or other nonspecialists from whom patients with SCD may often seek treatment. “Awareness of these guidelines is low,” Dr. Hsu said.
Key resources that can be helpful include evidence-based guidelines developed by an expert panel of the National Heart, Lung, and Blood Institute, and the American Society of Hematology has a Pocket Guide app on management of sickle cell disease.
Another key resource being highlighted in September, which is National Sickle Cell Disease Awareness Month, is the NHLBI’s comprehensive website, providing information ranging from fact sheets on the disease and treatments to social media resources and inspiring stories of people with SCD.
“We are trying to bring more sickle cell information and case studies into medical school curricula, nursing curricula, social workers and community health workers awareness, [and] apps and online guidelines are proliferating,” Dr. Hsu says.
He goes on to say, “We need more recognition and resources from insurance providers that quality care for sickle cell disease is measured and rewarded.”
Dr. Hsu coauthored “Hope and Destiny: The Patient and Parent’s Guide to Sickle Cell Disease and Sickle Cell Trait.” He reported relationships with Novartis, Emmaus, Forma Therapeutic, Dupont/Nemours Children’s Hospital, Hilton Publishing, Asklepion, Bayer, CRISPR/Vertex, Cyclerion, Pfizer, and Aruvant.