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Table 1 Baseline characteristics of the study groups

From: Effectiveness of topical vancomycin in the prevention of spinal surgical site infections: a retrospective cohort study

Baseline characteristics Vancomycin treated
N = 81
Vancomycin untreated
N = 375
Difference (p-value)
Age (years)
Median 50 45 0.06
IQR 27 22
Sex no. (%)
Male 47 (58.0) 249 (66.4) 0.19
Female 34 (42.0) 126 (33.6)
BMI (kg/m2)
Median 29.7 29.4 0.52
IQR 8.4 7.2
Type of surgery no. (%)
Lumbar 58 (72.0) 285 (76.0) < 0.01
Thoracic 5 (6.0) 5 (1.0)
Thoracolumbar 15 (18.0) 30 (8.0)
Cervical 3 (4.0) 55 (15.0)
Smoking history no. (%)
Never smokers 60 (74.0) 232 (62.0) 0.12
Current smokers 19 (23.0) 125 (33.3)  
Former smokers 2 (3.0) 18 (5.0)  
Diabetes mellitus no. (%) 20 (25.0) 64 (17.0) 0.14
Renal functions no. (%)
Normal 79 (98.0) 371 (99.0) 0.28
Abnormal 2 (2.0) 4 (1.0)  
Hypertension no. (%) 29 (36.0) 98 (26.0) 0.10
History of spinal infection no. (%) 4 (5.0) 3 (1.0) 0.02
History of spinal surgeries no. (%) 19 (23.0) 54 (14.0) 0.06
History of antibiotic use within 90 days before index date no. (%) 13 (16.0) 28 (8.0) 0.03
Prolonged operation time no. (%) 71 (88.0) 29 (8.0) < 0.01
Surgical approach no. (%)
Anterior 0 (0.0) 31 (8.0) < 0.01
Posterior 81 (100.0) 344 (92.0)
Implant no. (%) 72 (89.0) 184 (49.0) < 0.01
Alcohol as disinfectant no. (%) 70 (86.0) 303 (81.0) 0.30
Prophylactic gentamicin solution for irrigation no. (%) 68 (84.0) 281 (75.0) 0.11
Pre-operative white blood cell counts (in 10^3/µl)
Median 7.5 8.2 0.08
IQR 3.8 3.1
Pre-operative neutrophil counts (%)
Median 54.7 57.4 0.13
IQR 13.9 13.9