Risk-stratified survival data for 884 Mayo Clinic patients with primary myelofibrosis. *Very high-risk category includes patients with monosomal karyotype, inv(3)/i(17q) abnormalities, or any 2 of the following: Peripheral blood blasts > 9%, white blood cell ≥ 40 × 10⁹/L, other unfavorable karyotype (ie, nonmonosomal complex karyotype or any single or 2 abnormalities, including +8, −7/7q−, −5/5q−, inv(3), i(17q), 12p−, or 11q23 rearrangement). DIPSS-plus risk categorization is as described previously.¹