A meta-analysis comparing clinical characteristics and outcomes in CALR-mutated and JAK2V617F essential thrombocythaemia.

A systematic review and meta-analysis were carried out to compare the clinical features and outcomes in calreticulin (CALR)-mutated and JAK2V617F patients of essential thrombocythemia (ET). Compared with JAK2V617F ET patients, CALR-mutated ET was associated with a clear increase in male predominance [OR 1.71 (95 % CI 1.28-2.28), P < 0.001, I(2)) = 51.6] and a significant decrease in thrombosis events [OR 0.40 (95 % CI 0.32-0.50), P < 0.001, I(2) = 0]. No difference was observed in hemorrhagic events [OR 0.86 (95 % CI 0.52-1.42), P = 0.558, I(2) = 0] or splenomegaly [OR 0.8 (95 % CI 0.55-1.14), P = 0.217 I (2) = 42.9]. CALR-mutated ET did not show better overall survival (OS) [HR 1.03 (95 % CI 0.74-1.44) P = 0.854, I(2) = 47.6] but showed better thrombosis-free survival (TFS) [HR 0.62 (0.44-0.87), P = 0.005, I(2) = 0] than JAK2V617F ET. In conclusion, CALR-mutated ET and JAK2V617F ET may represent two different subgroups of essential thrombocythaemia with respect to clinical features and outcomes.