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Table 3 Univariate and Multivariable Analyses of Risk Factors for Recurrence

From: Appropriate duration of post-surgical intravenous antibiotic therapy for pyogenic spondylodiscitis

Risk factors No Recurrence (n = 76) Recurrence (n = 26) Univariate Analysis Multivariable Analysis
OR (95% CI) p value aOR (95% CI) p value
Age, y, mean 64 60 1.03 (0.99–1.07) 0.12   
Male sex 46 19 1.77 (0.66–4.72) 0.25   
Underlying illness
 Alcoholism 4 2 1.50 (0.26–8.71) 0.64   
 Diabetes mellitus 20 13 2.80 (1.11–7.05) 0.03   
 Liver cirrhosis 14 2 0.37 (0.08–1.75) 0.35   
 End-stage renal disease 11 8 2.63 (0.92–7.50) 0.08   
 Intravenous drug abuser 2 0 Not calculated    
 Malignancy 5 3 1.85 (0.41–8.36) 0.42   
Clinical data
 Time to surgery, d, mean 39 51 1.01 (0.99–1.02) 0.16   
 Back pain 71 24 0.99 (0.97–1.03) 0.55   
 Fever 27 7 0.67 (0.25–1.79) 0.48   
 Neurologic deficit 17 6 1.03 (0.95–1.07) 0.39   
 Concurrent metastatic infection 21 11 1.93 (0.76–4.85) 0.22   
Laboratory data (UNL)
 Abnormal WBC (11,500 cells/mL) 25 11 1.50 (0.60–3.73) 0.48   
 Abnormal ESR (30 mm/h) 76 26 Not calculated    
 Abnormal CRP (5 mg/L) 76 26 Not calculated    
 Positive blood culture 18 14 3.76 (1.48–9.58) 0.004 2.97 (1.13–7.91) 0.03
 Positive tissue culture 55 22 2.74 (0.93–8.05) 0.21   
 MRSA infection 14 11 3.25 (1.23–8.57) 0.02   
 MSSA infection 15 1 0.16 (0.02–1.30) 0.06   
Radiographic finding
 Cervical spine infection 3 0 Not calculated    
 Thoracic spine infection 14 4 0.81 (0.24–2.71) > 0.99   
 Lumbosacral spine infection 61 22 1.35 (0.41–4.52) 0.77   
 More than 2 levels 15 5 0.97 (0.31–2.99) > 0.99   
 Epidural abscess 23 15 2.30 (0.93–5.73) 0.09   
 Paraspinal abscess 11 11 4.33 (1.58–11.86) 0.003 3.36 (1.17–9.63) 0.02
Treatment data
 Anterior surgery 22 7 0.90 (0.33–2.45) > 0.99   
 Posterior surgery 30 12 1.31 (0.54–3.23) 0.65   
 A + P surgery 24 7 0.80 (0.30–2.15) 0.81   
 Instrumentation 39 9 0.50 (0.20–1.27) 0.18   
 Duration of pre-op antibiotics, d 10.2 8.4 1.00 (0.96–1.03) 0.84   
  1. Abbreviations: OR odds ratio, CI confidence interval, aOR adjusted odds ratio, UNL upper normal limit, WBC white blood cells, ESR erythrocyte sedimentation rate, CRP C-reactive protein, MSSA methicillin-susceptible Staphylococcus aureus, MRSA methicillin-resistant Staphylococcus aureus