In an article for The Huffington Post titled “A Patient Walks Into a Sleep Clinic With Too Many Red Blood Cells…,” Joseph Ojile, MD, FCCP, DABSM, explores the association between a high hematocrit (when the percentage of red blood cells is above the upper limits of normal) and sleep disorders. As obstructive sleep apnea (OSA) can be a possible cause of elevated red blood cell count, Ojile says primary care physicians should consider referring these patients for evaluation for OSA. A simple blood test administered by physicians can measure complete blood count.

Elevated Hematocrit and Health

Elevated hematocrit indicates a shortage of oxygen in a patient’s system—the body is creating more red blood cells to carry more oxygen to account for the shortage, says Ojile, who is a Sleep Review editorial advisory board member. It can be an indicator of severe illnesses, such as heart disease and stroke, as well as less threatening symptoms, including blurred vision. Ojile tells Sleep Review via e-mail, “Those with elevated hematocrit have an increased risk for blood clots, vascular injury, and fatigue, all of which increase as the hematocrit level rises.”

The Sleep Apnea Connection

In a 2006 study titled “Does Obstructive Sleep Apnea Increase Hematocrit?,” the authors concluded that sleep apnea alone is a risk factor for an increased hematocrit. The study, published in Sleep & Breathing, revealed that as the average oxygen saturation dropped, hematocrit increased. The low oxygen environment created by sleep apnea is a potential mechanism for elevating hematocrit and reducing oxygen, and as the oxygen decreases, the body aims to compensate for this. The body compensates in the following two ways, Ojile says: taking in more air, which is typically not possible in patients with OSA; and making more red blood cells to carry more oxygen and/or concentrate the red blood cells by decreasing the other elements that make up your blood.

The Huffington Post article notes that over time, the body becomes increasingly accustomed to low oxygen levels and the hematocrit remains elevated. As such, primary care physicians can be essential in helping treat patients with this condition with a referral to a sleep medicine specialist. Ojile says patients with elevated hematocrit and other risk factors and symptoms, such as high blood pressure, large neck circumference, or snoring, should be referred for sleep disorder evalution.

Lowering Hematocrit

A study published in Chest found that a small group of patients prescribed CPAP for treatment showed significant decreases in hematocrit levels. In addition, a European Respiratory Journal study followed patients for over a year and similar decreases in hematocrit levels were demonstrated. Ojile says, “CPAP is thought to improve overall oxygen delivery and indirectly results in reduced hemoglobin. However, this mechanism remains under discussion so it’s important to talk with your doctor before starting any kind of CPAP therapy.”

In addition to CPAP therapy, developing a comprehensive care plan with a patient’s primary care physician can be essential to good health. Ojile says, “Elevated hemoglobin is also related to other disease states such as severe COPD and primary blood disorder. Patients should always discuss their elevated hematocrit plan of treatment thoroughly with their primary care physician.”

Diagnosis and Care

As primary care physicians are often the initial point of care for patients, Ojile emphasizes the importance of these doctors in the diagnosis and care of patients with elevated hematocrit. He notes that an elevated hematocrit does not necessarily mean that a patient has sleep apnea, but writes in The Huffington Post article, “Over the years we have diagnosed and treated patients for OSA who have suffered at length with the effects of hypoxia because their health care providers did not consider a sleep disorder as the secondary source of their elevated hematocrit.”

As such, Ojile applauds the primary care physicians who are perceptive enough to refer patients with increased amounts of red blood cells to a sleep medicine professional for diagnosis. Ojile says, “The implication [for primary care physicians] is that this is a disorder that has bidirectional associations—that OSA and the elevated hematocrit are mutually impactful. Insightful primary care physicians realize this and send their patients with OSA symptoms and elevated hematocrit for sleep testing.”

Collaboration among healthcare professionals is also a vital component of patient care and treatment, especially for sleep medicine professionals. Ojile says, “Collaborating with our colleagues in primary care and hematology is vital to both diagnose and evaluate the differential diagnosis and therapy in a multidisciplinary way for the patient presenting with elevated hematocrit.”

Cassandra Perez is associate editor for Sleep Review.