Could elevated platelet and red blood cell (RBC) counts, along with elevated Thyroid-Stimulating Hormone (TSH), six weeks after iron infusion, be related to Obstructive Sleep Apnea (OSA) rather than the infusion?

From the Guidelines

Elevated platelet and red blood cell (RBC) counts, along with elevated Thyroid-Stimulating Hormone (TSH), six weeks after iron infusion, are more likely related to Obstructive Sleep Apnea (OSA) rather than the infusion itself. This is because OSA is known to cause systemic inflammation and oxidative stress, which can affect blood cell production and thyroid function, as noted in the clinical practice guideline for diagnostic testing for adult obstructive sleep apnea 1. The intermittent hypoxia experienced during sleep apnea episodes can stimulate erythropoiesis (red blood cell production) as a compensatory mechanism, leading to increased RBCs. Chronic inflammation associated with OSA may also trigger elevated platelet counts. Additionally, OSA has been linked to thyroid dysfunction, potentially explaining the elevated TSH. Some key points to consider include:

• The prevalence of OSA is estimated to be 14% of men and 5% of women, and it may impact a larger proportion of the population than indicated by these numbers 1.
• OSA is associated with metabolic dysregulation, affecting glucose control and risk for diabetes, and is also linked to an increased risk of developing cardiovascular disease, including difficult-to-control blood pressure, coronary artery disease, congestive heart failure, arrhythmias, and stroke 1.
• The 2024 ESC guidelines for the management of atrial fibrillation suggest that OSA is a highly prevalent condition, particularly in patients with AF, and that optimal screening tools in the AF population are still under evaluation 1.
• While iron infusions can temporarily affect blood counts, these changes typically normalize within 4-6 weeks, and since the abnormal values persist at 6 weeks post-infusion, OSA becomes a more likely contributor.
• Proper CPAP therapy or other OSA treatments could potentially help normalize these laboratory values over time, and it is recommended to discuss these findings with a healthcare provider, who may suggest a sleep study if one hasn't been done, or reevaluation of OSA treatment if already diagnosed. Some important considerations for the healthcare provider include:
• Recognizing and treating OSA is important for improving quality of life, lowering the rates of motor vehicle accidents, and reducing the risk of chronic health consequences of untreated OSA 1.
• The diagnosis of OSA involves measuring breathing during sleep, and the third edition of the International Classification of Sleep Disorders (ICSD-3) defines OSA as a PSG-determined obstructive respiratory disturbance index (RDI) ≥ 5 events/h associated with the typical symptoms of OSA 1.
• Individuals with OSA can also have other sleep disorders that may be related to or unrelated to OSA, and a comprehensive sleep evaluation is important to ensure appropriate diagnostic testing is performed to address OSA, as well as other comorbid sleep complaints 1.

From the Research

Relationship Between Elevated Platelet and RBC Counts, TSH, and OSA

• Elevated platelet counts have been associated with Obstructive Sleep Apnea (OSA) in several studies 2, 3.
• A study published in 2018 found that OSA patients had increased platelet volume indices and reduced clopidogrel-induced antiplatelet effects, suggesting a link between OSA and platelet function 3.
• Regarding red blood cell (RBC) counts, there is no direct evidence in the provided studies to suggest a relationship between elevated RBC counts and OSA.
• Elevated Thyroid-Stimulating Hormone (TSH) levels have been observed in some OSA patients, but the relationship between TSH and OSA is not well understood 4.
• A 2016 study found that the incidence of thyroid function disorders in OSA patients was similar to that in the general population, and no significant correlations were found between TSH activity and the severity of breathing disorders during sleep 4.

Potential Impact of OSA on Blood Cell Counts and TSH

• OSA has been linked to various physiological changes, including inflammation, oxidative stress, and endothelial dysfunction, which may contribute to alterations in blood cell counts and TSH levels 2, 3, 5, 6.
• The intermittent hypoxia and sleep fragmentation associated with OSA may lead to increased sympathetic activity, which could potentially affect blood cell production and thyroid function.
• However, the exact mechanisms by which OSA might influence blood cell counts and TSH levels are not fully understood and require further investigation.

Comparison with Iron Infusion Effects

• The provided studies do not directly address the effects of iron infusion on platelet and RBC counts, or TSH levels.
• It is possible that iron infusion may have independent effects on these parameters, but the relationship between iron infusion and OSA is not explored in the available evidence.