JAK2 and miotic rate: Univariable analysis disclosed female gender (OR 3.76; 95% CI 1.44–10.5; p = .009), hydroxyurea naïve (OR 0.27; 95% CI 0.10–0.70; p = .008), CHR responder (OR 20.9; 95% CI 6.39–85.1; p < .001), hematocrit responder (OR 16.7; 95% CI 4.79–79.6; p < .001), platelet responder (OR 9.46; 95% CI 1.50–184; p = .043), CHR responder at 12 weeks (OR 9.23; 95% CI 2.34–61.9; p = .005), and baseline JAK2 V617F allele burden (OR 1.03; 95% CI 1.01–1.06; p = .019) were significantly associated with MR.