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Table 1 Baseline characteristics of the patients before and after propensity score matching

From: Efficacy of capecitabine and oxaliplatin versus S-1 as adjuvant chemotherapy in gastric cancer after D2 lymph node dissection according to lymph node ratio and N stage

 Before propensity score matching (n = 477)After propensity score matching §(n = 220)
S-1 (n = 331)XELOX (n = 146)p value*Absolute‡ Standardized difference in %S-1 (n = 110)XELOX (n = 110)p value†Absolute‡ Standardized difference in %
Age (years)
  < 65181 (54.7)104 (71.2)0.00134.770 (63.6)68 (61.8)0.8893.7
  ≥ 65150 (45.3)42 (28.8) 34.740 (36.4)42 (38.2) 3.7
Sex
 Male225 (68.0)101 (69.2)0.7952.676 (69.1)76 (69.1)> 0.999< 0.001
 Female106 (32.0)45 (30.8) 2.634 (30.9)34 (30.9) < 0.001
ECOG
 0241 (72.8)124 (84.9)0.00430.086 (78.2)89 (80.9)0.7386.7
  ≥ 190 (27.2)22 (15.1) 30.024 (21.8)21 (19.1) 6.7
ASA score
 1 to 2308 (93.1)138 (94.5)0.5493.4100 (90.9)103 (93.6)0.6159.2
  ≥ 323 (6.9)8 (5.5) 3.410 (9.1)7 (6.4) 9.2
Location
 EGJ11 (3.3)7 (4.8)0.4377.4107 (97.3)108 (98.2)> 0.9996.1
 Other320 (96.7)139 (95.2) 7.43 (2.7)2 (1.8) 6.1
Stage (AJCC 7th edition)
 IIA109 (32.9)5 (3.4)< 0.00182.83 (2.7)4 (3.6)0.9825.2
 IIB73 (22.1)19 (13.0) 23.921 (19.1)19 (17.3) 4.7
 IIIA52 (15.7)39 (26.7) 27.228 (25.5)26 (23.6) 4.2
 IIIB53 (16.0)48 (32.9) 40.033 (30.0)34 (30.9) 2.0
 IIIC44 (13.3)35 (24.0) 27.725 (22.7)27 (24.5) 4.3
T stage
 T126 (7.9)3 (2.1)0.00127.04 (3.6)3 (2.7)> 0.9995.2
 T251 (15.4)10 (6.8) 27.58 (7.3)8 (7.3) 0.0
 T3129 (39.0)56 (38.4) 1.340 (36.4)40 (36.4) 0.0
 T4a,b125 (37.8)77 (52.7) 30.458 (52.7)59 (53.6) 1.8
N stage
 N087 (26.3)9 (6.2)< 0.00156.79 (8.2)9 (8.2)0.9860.0
 N167 (20.2)28 (19.2) 2.716 (14.5)17 (15.5) 2.5
 N2103 (31.1)38 (26.0) 11.339 (35.5)36 (32.7) 5.8
 N374 (22.4)71 (48.6) 57.146 (41.8)48 (43.6) 3.7
Number of dissected lymph nodes
 mean ± sd47.0 ± 18.852.4 ± 17.1< 0.00130.051.4 ± 21.451.5 ± 16.50.4930.7
 median (IQR)43 (35–55)52 (39–65)  45 (37–64)52 (39–62)  
LNR group
 LNR 088 (26.6)9 (6.2)< 0.00140.268 (61.8)66 (60.0)0.893.7
 LNR 1127 (38.4)49 (33.6) 40.242 (38.2)44 (40.0) 3.7
 LNR 278 (23.6)47 (32.2)      
 LNR 338 (11.5)41 (28.1)< 0.00157.49 (8.2)9 (8.2)0.9940.0
Tumor size (cm)   10.036 (32.7)35 (31.8) 1.9
  < 6250 (75.5)83 (56.8) 19.339 (35.5)41 (37.3) 3.8
  ≥ 681 (24.5)63 (43.2) 42.626 (23.6)25 (22.7) 2.2
Differentiation
 Well to moderately114 (34.4)34 (23.3)0.01524.825 (22.7)28 (25.5)0.7536.4
 Poorly217 (65.6)112 (76.7) 24.885 (77.3)82 (74.5) 6.4
Lauren classification
 Intestinal118 (35.6)39 (26.7)0.11119.430 (27.3)34 (30.9)0.7328.0
 Diffuse96 (29.0)43 (29.5) 1.037 (33.6)32 (29.1) 9.8
 Mixed117 (35.3)64 (43.8) 17.443 (39.1)44 (40.0) 1.9
Lymphovascular invasion
 no90 (27.2)13 (8.9)< 0.00150.28 (7.3)13 (11.8)0.3598.9
 yes241 (72.8)133 (91.1) 50.2102 (92.7)97 (88.2) 8.9
Perineural invasion
 no161 (48.6)49 (33.6)0.00230.940 (36.4)39 (35.5)> 0.9991.9
 yes170 (51.4)97 (66.4) 30.970 (63.6)71 (64.5) 1.9
Completion of planned chemotherapy
 no69 (20.8)42 (28.8)0.05918.425 (22.7)26 (23.6)> 0.9992.1
 yes262 (79.2)104 (71.2) 18.485 (77.3)84 (76.4) 2.1
CEA (ng/ml)
  < 5315 (95.2)140 (95.9)0.7283.5106 (96.4)106 (96.4)> 0.999< 0.001
  ≥ 516 (4.8)6 (4.1) 3.54 (3.6)4 (3.6) < 0.001
CA 19–9 (U/ml)
  < 37.0308 (93.1)132 (90.4)0.3209.6100 (90.9)102 (92.7)0.8069.7
  ≥ 37.023 (6.9)14 (9.6) 9.610 (9.1)8 (7.3) 9.7
  1. Data are presented as the n (%) for categorical variable, unless otherwise indicated
  2. *P value from Wilcoxon rank sum test for continuous variables or Chi-square test, for categorical variables in before Propensity score matching data
  3. P value from Wilcoxon signed rank sum test for continuous variables or Chi-square test, for categorical variables in matched data
  4. ‡no covariates would be considered imbalanced if the threshold was set at either 0.10 (Normand et al. 2001) or 0.25 (Rubin 2001)
  5. §matched using digit-based greedy (“greedy”)