Table 2.
Hazard-ratios of treatment failure in univariate Cox regression analysis
| HR | CI95% | p-value | |
|---|---|---|---|
| Sex (male) | 1.02 | [0.98, 1.05] | 0.326 |
| Age (years) | 0.84 | [0.33, 2.16] | 0.723 |
| Body mass index (kg/m²) | 1.00 | [0.98, 1.02] | 0.869 |
| Diabetes mellitus | 2.17 | [0.82, 5.72] | 0.118 |
| Autoimmune disease | Inf | [0, Inf] | 0.997 |
| Active cancer | 0.88 | [0.62, 1.23] | 0.441 |
| Active smoking | 2.26 | [0.85, 6.04] | 0.103 |
| Charlson comorbidity index | 1.10 | [0.97, 1.26] | 0.130 |
| ASA score | 2.07 | [1.07, 4.03] | 0.031 |
| Hip | 1.08 | [0.39, 3.02] | 0.885 |
| Knee | 0.88 | [0.31, 2.46] | 0.807 |
| Primary implantation | 1.25 | [0.29, 5.41] | 0.767 |
| Staphylococcus aureus | 4.03 | [0.54, 30.27] | 0.175 |
| MRSA | 2.56 | [0.73, 8.94] | 0.140 |
| Total duration of antibiotic therapy (days) | 0.98 | [0.97, 0.99] | 0.002 |
| Rifampin use | 0.17 | [0.06, 0.45] | <0.001 |
| Rifampin + fluoroquinolone | 0.19 | [0.07, 0.53] | 0.002 |
| Daily rifampin dose (mg/kg/day) | 1.00 | [0.88, 1.13] | 0.958 |
| Delay between debridement and rifampin introduction (days) | 0.99 | [0.95, 1.03] | 0.488 |
| Duration of rifampin (days) | 0.97 | [0.95, 1] | 0.022 |
| Drug-related adverse event | 0.52 | [0.15, 1.79] | 0.299 |
| Drug-related adverse event leading to rifampin interruption | Inf | [0, Inf] | 0.998 |
| Removal of polyethylene components | 1.19 | [0.36, 3.92] | 0.778 |
| Arthrotomy | Inf | [0, Inf] | 0.998 |
| Time to infection (days) | 1.02 | [0.94, 1.09] | 0.674 |
HR: hazard-ratio; CI95%: 95% confidence interval; ASA: American Society of Anesthesiologists (a clinical scoring system widely used to assess pre-operative clinical status); MRSA: methicillin-resistant Staphylococcus aureus.