PB2050: EVALUATION OF NON-CLONAL ERYTHROCYTOSIS: SINGLE CENTRE EXPERIENCE

Abstract

Background: Secondary erythrocytosis has a broad differential diagnosis that includes hypoxic lung disease, cyanotic congenital heart disease, kidney disease, medications and erythropoietin-producing malignant disorders. Aetiology remains unknown in some patients, they have the so-called idiopathic erythrocytosis (IE). Among the latter, patients with inherited/congenital erythrocytosis can be found, especially if they have a positive family history. Aims: The aim of our study was to analyse the characteristics of non-clonal erythrocytosis in patients referred to our Haematology department in a 5-year period (2016 – 2021) and to compare the IE group to the group with known causes. Methods: We included all individuals who were Janus kinase 2 (JAK2) mutation negative and had erythrocytosis. Data was retrospectively collected with the help of the hospital database and statistically analysed with SPSS. Results: The study included 250 patients, 176 (70%) men and 74 (30%) women, with mean age 58.8 years (21 – 94 years). Their average haemoglobin values within a 1-year time period were 182.5 g/L for men and 169 g/L for women. Average haematocrit levels were 0.53 for men and 0.50 for women. Elevated erythropoietin (EPO) levels were found in 10.5% patients, 83.4% had normal and 6.1% decreased values. Symptoms were reported by 48% of the patients, mostly itchiness (16.4%), sweating (12%) and other (30%) such as tinnitus, myalgia, joint pain and snoring. The most probable reasons for secondary erythrocytosis were smoking/chronic obstructive pulmonary disease (COPD) (32%), IE (29%), dehydration (7%), nephrological aetiology (6%), obesity (4%), sleep apnoea (4%), asthma (4%), infection (4%), heart or pulmonary disease hypoxia (4%), possible hemochromatosis (3%), medications (2%) and high altitude/training (1%). Patients with IE had an average age of 57.2 years (24 – 83 years), 57 (78%) were men and 8 (11%) had a positive family history. EPO levels in this group were elevated in 7.8%, normal in 88.2% and decreased in 3.9%. Past thrombotic events were reported by 23.3% of individuals with IE and 20.3% of patients with known secondary cause. There was no statistical difference in age, gender, EPO, haemoglobin levels and past thrombotic events between the IE group and group with known causes. Patients with IE significantly differed from the group with known causes in haematocrit levels (p=0.0219) with lower levels in IE patients. Summary/Conclusion: Among 250 patients with non-clonal erythrocytosis the majority had acquired aetiology. The most common cause was hypoxia caused by smoking or COPD. Patients with IE significantly differed from the group with known causes in haematocrit levels, while there were no significant differences between groups in age, gender, EPO levels, haemoglobin levels and past thrombotic events.