Table 3. Studies evaluating outcomes in essential thrombocythemia.

	Passamonti et al.11	Chim et al.29	Wolanskyj et al.28	Gangat et al.37	Passamonti et al.30	Palandri et al.31	Girodon et al.35	Abdulkarim et al.16	Barbui et al.34	Malak et al.32	Tefferi et al.2
N	435	231	322	605	605	386	311	130	891	105	292 (Mayo) 284 (Italy)
Median F/U (years)	9.3	NR	13.6	7	5.6	9.5	9.5	15	6.2	7.5	17.3 10.7
MF
N	1.6 (0.8–3.4)a	7 (3%)	NRb	NR	17 (2.8%)	20 (5%)	NR	7 (5%)	32 (4%)	12 (13%)	29 (9.9%) 26 (9.2%)
Median time to MF from Dx (years)	10.9	8	12.4	NR	9.1	7.25	NR	NR	NR	16	NR
Risk factors	NR	NR	None	NR	Anemiac	Sequential use of cytotoxic drugs	NR	Anemia Leukocytosis Reticulin BM cellularity	BM histology Age >60 years Hgb<120 g/l Absent JAK2V617F	None	MPL mutated
Leukemia
N	1.2 (0.5–2.8)a	4 (1.7%)	NRd	20 (3.3%)	14 (2.3%)	6 (1.5%)	18 (5.8%)	11 (8%)	8 (1%)	7 (10%)	12 (4.1%) 4 (1.4%)
Median time to LT from Dx (years)	14.5	10	13.8	11.5	11	8.5	6.3	NR	NR	7.4	NR
Risk factors	None	Previous MF Melphalan WBC>11 × 109/l	None	Anemiae Plts ⩾1000 × 109/l Age (continuous variable)	Age >60 years	Sequential use of cytotoxic drugs	None	Anemia Leukocytosis Reticulin BM cellularity	BM histology Thrombosis Plts>1000 × 109/l	None	None
Median survival (years)	22.6	13	18.9	18	22.3	NR	11	NRf	14.7	NRg	19.8h
Risk factors	Thrombosis Male	Age >60 years	Age ⩾60 years WBC⩾15 × 109/l Tobacco use DM	Age ⩾60 years WBC⩾15 × 109/l Anemiae Thrombosis DM Smoking	Age >60 years Thrombosis	Age ⩾60 years WBC⩾15 × 109/l HTN DM Thrombosis	Age >60 years WBC>11 × 109/l Anemia	Anemia	Age >60 years WBC>11 × 109/l Hgb <120 g/l Thrombosis BM histology	NR	Age ⩾60 years

Abbreviations: BM, bone marrow; DM, diabetes mellitus; Dx, diagnosis; HTN, hypertension; HU, hydroxyurea; LT, leukemic transformation; MF, myelofibrosis; NR, not reported; Plts, platelets; WBC, white blood cell.

^aIncidence per 1000 person-years (95% CI).

^b3.8% cumulative probability of MF transformation at 10 years (95% CI=1.4–6.1).

^cHgb<125 g/l in females, <135 g/l in males.

^d1.4% 10-year cumulative probability of AML transformation (95% CI=0–3).

^eHgb<120 g/l in females, <135 g/l in males.

^fOverall survival 58% at 10 years.

^gOverall survival 83% at 10 years.

^hBased on Mayo cohort.