In chronically transfused adults with sickle cell disease (SCD), a retrospective analysis found that a substantial subgroup experienced sleep-associated hemoglobin desaturation (SpO₂ ≤ 88% for ≥5 minutes), which was associated with markers of hemolysis and inflammation, underscoring the need to consider sleep-related hypoxemia in comprehensive SCD care.

Key Findings

• Purpose
  To characterize the prevalence and clinical correlates of nocturnal hemoglobin desaturation (NHD) in adults with SCD managed with chronic red blood cell exchange transfusion.
• Population
  A retrospective cohort of 41 chronically transfused adults with SCD identified from clinical records; 15 individuals (36.6%) had documented NHD prior to study inclusion.
• Headline Result
  Among participants:
  • NHD was defined as ≥5 minutes at SpO₂ ≤ 88% during sleep-associated monitoring.
  • Those with NHD had higher absolute reticulocyte counts (P = .018) and higher white blood cell counts (P = .05) compared with those without NHD.
  • Trends toward lower hemoglobin levels (P = .11) and higher lactate dehydrogenase (LDH) were noted in the NHD group, although not all comparisons reached statistical significance.
• Why It Matters
  Recurrent or prolonged nocturnal hypoxemia may contribute to systemic stress, hemolytic severity, and end-organ stress in adults with SCD, even among those receiving chronic transfusion therapy. Recognition of nocturnal desaturation could prompt targeted evaluation (eg, overnight oximetry) and tailored management (eg, sleep evaluation, transfusion optimization, or respiratory support) in vulnerable adults.
• Evidence Gaps & Limitations
  Retrospective design limits causal inferences and may underdetect asymptomatic desaturation; objective sleep study data (polysomnography) and longitudinal outcomes (eg, hospitalization rates, quality of life, stroke risk) were not captured. Results may not generalize beyond adults on chronic exchange transfusion regimens or settings with comprehensive monitoring.

Source: Journal of Sickle Cell Disease — “Nocturnal hemoglobin desaturation in chronically transfused adults with sickle cell disease: a retrospective study.”

Regulatory & Guideline Watch

Existing SCD clinical practice guidelines (including NIH/ASH) recognize hypoxia as a risk factor for complications such as pulmonary hypertension and stroke but do not currently provide specific recommendations on routine nocturnal oxygen assessment in adults with SCD. Increased awareness of nocturnal desaturation could inform future guideline considerations for respiratory screening in high-risk cohorts.