Anemia in Patients Undergoing Therapeutic Phlebotomy for Polycythemia Secondary to COPD and OSA

Background: Therapeutic phlebotomy is performed to relieve symptoms of secondary polycythemia in chronic hypoxic lung diseases such as chronic obstructive pulmonary disorder (COPD) and obstructive sleep apnea (OSA). Excessive phlebotomy may cause iron deficiency anemia, leading to hypoxemia and resulting in vicious cycle of further erythropoiesis and hyper viscosity. Also, anemia of chronic disease is prevalent both in COPD and OSA patients due to the underlying systemic inflammation. Our aim is to find if adult patients develop anemia while undergoing prolonged therapeutic phlebotomy treatments. Methods: We retrospectively reviewed all outpatients that have undergone therapeutic phlebotomy from September 2018 to July 2024 in our ambulatory outpatient clinic for demographic and relevant clinical and laboratory data including hematologic indices. Cumulative incidence that represents the cumulative probabilities of anemia was computed from the life table using the Kaplan Meier method. Continuous variables with non-normal distribution are presented as median (interquartile range [IQR]). Results: The cohort had 19 patients among which 74% are males. Fifty eight percent were diagnosed with OSA and the remaining with COPD. The majority (68%) of patients belong to White race. The age of patients at their first therapeutic phlebotomy at our institution is 62 (IQR, 55-74) years and the median body mass index (BMI) is 31.9 (28.6 -36.6) kg/m2. The baseline hemoglobin is 18 (17-19) g/dL. The total number of therapeutic phlebotomy procedures done is 8 (4-12). The duration between the first therapeutic phlebotomy at our institution and the last one reviewed is 210 days (121-385). The cumulative incidence of anemia after 10 procedures is 37%. Conclusions: The incidence of anemia is high in patients undergoing therapeutic phlebotomy for mitigating symptoms of secondary polycythemia. Careful and regular monitoring is necessary to prevent anemia in this at-risk population.