Table 2.

Risk factors for venous thromboembolism in our cohort (n = 1308).

Variable	No.	2-Year cumulative rate, %	Univariate		Multivariate
			HR (95%CI)	P-valuea	HR (95%CI)	P-valuea
Age				0.009		0.016
<60 years	705	14.1	1		1
⩾60 years	603	19.3	1.42 (1.09–1.86)		1.46 (1.07–1.99)
CA-125 levels				0.003		0.025
⩽35 IU/L	132	5.8	1		1
>35 IU/L	1061	17.0	2.52 (1.33–4.76)		2.38 (1.11–5.07)
Thrombocytosisb				0.0001		0.032
No	860	13.8	1		1
Yes	434	22.3	1.66 (1.26–2.18)		1.42 (1.03–1.96)
Residual tumour size after surgery				0.028		0.52
>1 cm	353	20.2	1		1
⩽4 cm	897	13.6	0.72 (0.53–0.97)		0.89 (0.63–1.27)
Stage-specific histologic type				<0.0001
Advanced SOC	836	16.2	1		1
Advanced OCCC	106	43.1	2.74 (1.92–3.92)		3.38 (2.28–5.01)	<0.0001
Early-stage SOC	102	6.4	0.54 (0.28–1.03)		0.80 (0.38–1.68)	0.55
Early-stage OCCC	264	11.9	0.73 (0.50–1.06)		1.23 (0.77–1.95)	0.39

Abbreviations: HR, hazard ratio; CI, confidence interval; CA-125, cancer antigen 125; SOC, serous ovarian carcinoma; OCCC, ovarian clear cell carcinoma.

^aThe log-rank test was used for univariate analysis and Cox proportional hazards regression modelling was used for multivariate analysis.

^bPlatelet count ⩾ 400 × 10⁹/L.