Table 2. Analysis of recurrence-free survival (%) and univariate Cox regression, according to demographic variables, performance status, drained volume and PH.

Variables	n cases	n events	Recurrence-free survival (%)			Hazard ratio	95% CI	P
			6 months#	12 months#	P (K-M)
Overall	288	56	76.6	73.3	–	–	–	–
Gender
Male	108	21	74.1	74.1	0.961	1.00
Female*	179	35	78.1	73.0		0.99	0.57–1.70	0.961
Age
<60 years	134	32	73.9	67.9	0.116	1.00
≥60 years*	153	24	78.6	78.6		0.66	0.39–1.12	0.121
Main procedure
Chest drain	119	29	66.4	66.4	<0.001	1.00
indwelling pleural drain	28	2	79.7	XX+		0.28	0.07–1.17	0.081
Pleurodesis	124	13	88.6	84.6		0.33	0.17–0.63	0.001
Thoracocentesis	17	12	35.3	17.6		4.74	2.40–9.36	<0.001
ASA
I/II	138	25	78.2	76.0	0.229	1.00
III/IV*	149	31	75.4	70.8		1.38	0.81–2.34	0.234
ECOG
0/1	68	11	82.4	79.3	0.259	1.00
2	120	25	76.7	72.2		1.49	0.73–3.04	0.269
3/4*	99	20	72.1	72.1		1.85	0.88–3.90	0.106
Drained volume
>1,000 mL*	125	30	74.1	69.4	0.180	1.00
≤1,000 mL*	140	24	76.5	74.0		0.70	0.41–1.19	0.185
PH
7.35 to 7.45*	25	5	77.8	77.8	0.907	1.00
Other values	215	43	76.6	72.5		0.95	0.38–2.39	0.907
Primary site*
Breast	79	19	74.9	68.9	0.035	1.00
Lung	104	14	85.0	82.3		0.54	0.27–1.07	0.077
Gynecological	27	2	89.9	89.9		0.35	0.08–1.50	0.158
Gastric	35	11	29.4	XX†		1.74	0.82–3.69	0.150
Urological	15	3	71.8	71.8		0.85	0.25–2.88	0.795
Others sites	27	7	70.0	70.0		1.17	0.49–2.78	0.728

*, missing value; XX⁺, follow-up carried out until the 8^th month; K-M, Kaplan-Meier; XX^†, follow-up carried out until the 6^th month; ^#, lost of follow-up at 6^th months =13.9% (n= 40) patients and 12^th months =17.8% (n= 51) patients.