Atrial Fibrillation More Common in Adults with Sickle Cell Disease

Atrial fibrillation is more prevalent and occurring much earlier in life among patients with sickle cell disease than the general population, according to findings of a retrospective cohort analysis presented at the American Society of Hematology (ASH) 2021 Meeting in Atlanta this weekend.

In new data presented by a team of Chicago investigators, it is suggested that the greater incidence of atrial fibrillation in patients with the hematologic disorder may be a contributing factor to the patient population’s plateaued life expectancy, as well as their increased use of cardiovascular and nephrological medications.

Investigators, led by Chinonso Michelle Ukeje, MD, of the University of Illinois at Chicago School of Medicine, sought to determine the prevalence, incidence, and key clinical characteristics of atrial fibrillation in a cohort of patients with sickle cell disease. As they noted, the prevalence and risk factors for atrial fibrillation remains unclear in these patients.

“Life expectancy amongst individuals with sickle cell disease has plateaued, with cardiopulmonary complications now becoming a leading cause of death,” they wrote. “Indeed, sickle cell disease is associated with increased rates of pulmonary hypertension and diastolic dysfunction.”

Ukeje and colleagues conducted a retrospective, longitudinal cohort trial observing adult patients with sickle cell disease treated at the university’s care center from 2008 – 2017. Sickle cell disease was identified via automated direct chart review; atrial fibrillation was identified via manual review of approximately 17,000 available electrocardiograms of subjects assessed for the condition.

The final cohort included 763 adults with sickle cell disease; median patient age was 27.95 years old, with 59.5% being female. Approximately three-fourths (72.4%) had Hb SS or Sβ0-thalassemia genotype; another two-thirds (61.2%) were treated with hydroxyurea. Mean observation time for the cohort was 8.3 years.

Among the cohort, atrial fibrillation was identified in 30 patients (3.9%; 3.02 per 1000 patient years). Mean age of onset was 51 years. Investigators observed no differences in gender, ethnicity, or sickle cell disease genotype between sickle cell patients with and without atrial fibrillation.

On average, patients with sickle cell disease and atrial fibrillation were older at initial care (40 vs 25 years; P <.0001) and follow-up visits (53 vs 35 years; P <.0001), and were observed for nearly 4 years longer (13.3 vs 9.5 years; P = .0014) than sickle cell patients without atrial fibrillation.

What’s more, patients with atrial fibrillation and sickle cell disease were more likely to carry chronic disease diagnoses:

• Chronic obstructive pulmonary disease (P = .0004)
• Hypertension (P <.0001)
• Chronic kidney disease (P <.0001)
• Type 2 diabetes (P <.0001)
• Any cancer (P = .04

Though hydroxyurea use was not associated with increased risk of atrial fibrillation, sickle cell patients with atrial fibrillation were more likely to receive diuretics, atrioventricular nodal blocking agents, antihypertensives, antiplatelets, and statins. Such patients were also more likely to have worse anemia and renal function.

“We showed that the prevalence and incidence of atrial fibrillation is high in patients with sickle cell disease with the median age of onset occurring 1-2 decades earlier than in the general populace,” investigators wrote.

Atrial fibrillation in patients with sickle cell disease was associated with older age, worsened renal function and anemia, and increased use of medications. Ukeje and colleagues concluded that further analysis is warranted on the basis of these findings.

“The high incidence of atrial fibrillation in patients with sickle cell disease may contribute to the plateauing of life expectancy and identifying the causative risk factors and the underlying mechanisms may not only improve life expectancy but also the quality of life,” they wrote.

The study, “The Burden of Atrial Fibrillation in Sickle Cell Disease,” was presented at ASH 2021.