Obstructive sleep apnea (OSA) affects millions of adults in the United States, yet many people remain unaware they have the condition. OSA is linked to serious health problems such as high blood pressure, heart disease, and impaired daytime functioning. The disorder is typically diagnosed using pulse oximetry, a non-invasive tool that monitors blood oxygen saturation. However, previous research has shown that pulse oximeters can overestimate oxygen levels and may be less accurate in individuals with darker skin tones.
Two main definitions are used by the American Academy of Sleep Medicine for diagnosing OSA: one uses a 30% airflow reduction combined with either a 3% drop in oxygen saturation or an EEG arousal; the other uses a 30% airflow reduction and a 4% drop in oxygen saturation. Insurance providers like the Centers for Medicare and Medicaid Services often require only the stricter 4% threshold to confirm an OSA diagnosis, which could limit patient access to treatment.
A recent study from Boston University Chobanian & Avedisian School of Medicine examined whether these thresholds contribute to racial disparities in OSA diagnosis. The study found no racial differences in diagnoses among their group despite known limitations of pulse oximetry related to skin tone. However, women were less likely than men to meet the 4% desaturation threshold required for diagnosis under current insurance guidelines.
"While the use of the 4% rule compared to the 3% leads to a significant number of patients being excluded from OSA treatment, reassuringly, this does not appear to discriminate by race in our cohort. Female patients, on the other hand, are likely disadvantaged by the 4% rule," said Sanford Auerbach, MD, associate professor of neurology at Boston University and sleep specialist at Boston Medical Center.
Researchers reviewed records from more than 1,300 adults who had overnight sleep studies at an urban academic hospital. They collected data on medical history and demographics including age, sex, body mass index (BMI), anxiety and depression status, hypertension history, chronic obstructive pulmonary disease (COPD), and smoking status.
The study's authors recommend further research into improving pulse oximetry technology so it works effectively across all populations. They also suggest replacing the stricter 4% rule with the more inclusive 3% rule as a step toward broader access to treatment and greater equity in healthcare.
The findings are published online in the Journal of Clinical Medicine.
