Table 1 Baseline characteristics of the derivation and external validation cohorts

Male sex

753 (56.5)

362 (54.3)

391 (58.6)

Age

61.7 (22.0–96.0)

61.38 (22.0–92.0)

62.03 (28.0–96.0)

BMI

23.1 (13.4–32.1)

23.2 (15.2–31.8)

23.1 (13.4–32.1)

Smoking status

268 (20.1)

137 (20.5)

131 (19.6)

ECOG ≤ 2

671 (50.3)

331 (49.6)

340 (50.9)

History of VTE

46 (3.5)

24 (3.6)

22 (3.3)

Family history of thrombosis

24 (1.8)

6 (0.9)

18 (2.7)

Relevant comorbidities

 Hypertension

338 (25.3)

174 (26.1)

164 (24.6)

 Diabetes

123 (9.2)

65 (9.7)

58 (8.7)

 Coronary heart disease

47 (3.5)

26 (3.9)

21 (3.1)

 Heart disease

50 (3.8)

18 (2.7)

32 (4.8)

 Stroke

29 (2.2)

14 (2.1)

15 (2.2)

 Recent fracture

123 (9.2)

68 (10.2)

55 (8.2)

 Hyperlipidaemia

28 (2.1)

17 (2.5)

11 (1.6)

 Rheumatic diseases

10 (0.8)

4 (0.6)

6 (0.9)

 COPD or abnormal pulmonary function

63 (4.7)

23 (3.4)

40 (6)

 Recent infection

38 (2.9)

16 (2.4)

22 (3.3)

 Digestive diseases

13 (1.0)

7 (1)

6 (0.9)

 Hepatitis B

58 (4.4)

27 (4)

31 (4.6)

 Tuberculosis

21 (1.6)

13 (1.9)

8 (1.2)

 Other malignancy

32 (2.4)

19 (2.8)

13 (1.9)

Estrogen

2 (0.1)

2 (0.3)

0 (0)

Erythropoietin

48 (3.6)

21 (3.1)

27 (4.0)

Radiation

10 (0.8)

6 (0.9)

4 (0.6)

Recent immobilization

80 (6.0)

37 (5.5)

43 (6.4)

Central venous catheter or pacemaker

276 (20.7)

136 (20.4)

140 (20.9)

ISS stage

 I

220 (16.5)

117 (17.5)

103 (15.4)

 II

509 (38.2)

253 (37.9)

256 (38.4)

 III

605 (45.4)

297 (44.5)

308 (46.2)

M protein type

 Light chain

304 (22.8)

148 (22.2)

156 (23.4)

 Nonlight chain

1030 (77.2)

519 (77.8)

511 (76.6)

 IgG

719 (53.9)

357 (53.5)

362 (54.3)

 Non-IgG

615 (46.1)

310 (46.5)

305 (45.7)

Combined with amyloidosis

44 (3.3)

17 (2.5)

27 (4.0)

Disease stage

 NDMM

1096 (82.2)

554 (83.1)

542 (81.3)

 RRMM

238 (17.8)

113 (16.9)

125 (18.7)

Treatment stage

 Induction therapy

793 (59.5)

388 (58.2)

405 (60.7)

 Maintenance therapy

541 (40.6)

279 (41.8)

262 (39.3)

ASCT eligible

191 (14.3)

94 (14.1)

97 (14.5)

IMiD type

 Thalidomide

871 (65.3)

436 (65.4)

435 (65.2)

 Lenalidomide

463 (34.7)

231 (34.6)

232 (34.8)

Concurrent anticoagulant or antiplatelet drug

 Antiplatelet drug

507 (38.0)

251 (37.6)

256 (38.4)

 Anticoagulant

45 (3.4)

22 (3.3)

23 (3.4)

Concurrent chemotherapy

 Single

332 (24.9)

175 (26.2)

157 (23.5)

 Dexamethasone

1002 (75.1)

492 (73.8)

510 (76.5)

 Bortezomib

403 (30.2)

207 (31.0)

196 (29.4)

 Cyclophosphamide

245 (18.4)

126 (18.9)

119 (17.8)

 Doxorubicin

209 (15.7)

111 (16.6)

98 (14.7)

 Multiagent (≥ 3 drugs)

673 (50.5)

341 (51.1)

332 (49.8)

Laboratory data

 PT (s)

12.63 (7.00-26.50)

12.68 (7.00-26.50)

12.58 (7.00-25.50)

 APTT (s)

29.53 (11.10–77.00)

29.61 (14.5–77.00)

29.44 (11.10–73.20)

 FIB (g/L)

3.17 (0.10–9.50)

3.14 (0.10–9.50)

3.19 (0.29–8.38)

 Dimer (mg/L FEU)

1.87 (0.03-64.00)

1.89 (0.03-39.0)

1.85 (0.07-64.00)

 WBC (*10⁹/L)

5.25 (1.10-34.98)

5.24 (1.10–23.20)

5.27 (1.27–34.98)

 Hb (g/L)

99.41 (32.20–193.00)

99.52 (32.20–165.00)

99.29 (33.00-193.00)

 PLT (*10⁹/L)

181.93 (11.00-1329.00)

180.90 (11.00-1329.00)

182.99 (20.00-1329.00)

 Cr (µmol/L)

111.69 (16.20–1162.00)

108.66 (25.00-1162.00)

114.68 (16.20–951.00)

 ALB (g/L)

35.75 (12.00-49.90)

35.74 (12.00-49.90)

35.77 (15.90–48.70)

 LDH (U/L)

194.67 (48.00-974.00)

200.82 (48.00-974.00)

188.50 (76.00-615.00)

 BM2G (µg/L)

5499.84 (260.00-58000.00)

5463.79 (260.00-58000.00)

5535.70 (320.00-43777.62)

 LDL (mmol/L)

2.54 (0.32–11.33)

2.53 (0.32–11.28)

2.54 (0.35–11.33)

 TG (mmol/L)

2.24 (0.16–20.83)

2.27 (0.16–16.72)

2.22 (0.27–20.83)

 CHOL (mmol/L)

4.40 (0.91–24.35)

4.42 (0.96–24.35)

4.38 (0.91–17.44)

VTE

82 (6.1)

41 (6.1)

41 (6.1)

 Lower extremity

65 (4.9)

34 (5.1)

31 (4.6)

 Pulmonary embolism

6 (0.4)

3 (0.4)

3 (0.4)

 Upper extremity

11 (0.8)

4 (0.6)

7 (1.1)