Table 2.
Bivariate and Multivariate Cox Regression Model to Estimate Recurrence
| Groups | Crude HR (95% CI) | Adjusted HR (95% CI) |
|---|---|---|
| Rifampin treatment | ||
| No rifampin | Reference | Reference |
| Active rifampin treatment (days 1–90) | 0.57 (.43–.75) | 0.60 (.45–.79) |
| Active rifampin treatment (days 91–180) | 0.15 (.04–.59) | 0.16 (.04–.66) |
| Active rifampin treatment (days 181–731) | 0.43 (.14–1.37) | 0.57 (.18–1.81) |
| Postrifampin treatment (total ≤90 d) | 1.09 (.93–1.27) | 1.12 (.95–1.31) |
| Postrifampin treatment (total >90 d) | 1.03 (.74–1.42) | 1.07 (.75–1.51) |
| Age, y | ||
| <45 | Reference | Reference |
| 45–54 | 1.51 (1.05–2.16) | 1.33 (.93–1.90) |
| 55–64 | 1.52 (1.07–2.14) | 1.30 (.93–1.82) |
| 65–74 | 1.49 (1.04–2.12) | 1.20 (.85–1.69) |
| 75–84 | 1.51 (1.05–2.18) | 1.10 (.76–1.57) |
| ≥85 | 1.85 (1.24–2.77) | 1.06 (.70–1.63) |
| Sex | ||
| Male | 0.98 (.75–1.27) | NAa |
| Female | Reference | NAa |
| Race | ||
| White | 1.01 (.85–1.21) | 1.16 (.95–1.42) |
| Black | 0.91 (.74–1.12) | 1.03 (.82–1.29) |
| Other | Reference | Reference |
| BMI, kg/m2 | ||
| Normal (BMI ≥20 and <25) | Reference | Reference |
| Underweight (BMI <20) | 0.96 (.64–1.44) | 1.08 (.71–1.64) |
| Overweight (BMI ≥25 and <30) | 0.79 (.69–.92) | 0.83 (.70–.97) |
| Obese (BMI ≥30) | 0.81 (.70–.92) | 0.88 (.76–1.02) |
| Year of PJI | ||
| 2003–2004 | Reference | Reference |
| 2005–2007 | 0.85 (.70–1.03) | 0.92 (.75–1.13) |
| 2008–2010 | 0.82 (.68–1.00) | 0.90 (.73–1.09) |
| 2011–2013 | 0.73 (.61–.89) | 0.73 (.60–.90) |
| 2014–2016 | 0.70 (.57–.85) | 0.69 (.56–.85) |
| 2017–2019 | 0.68 (.56–.83) | 0.66 (.54–.81) |
| Geographic area | ||
| Northeast | 0.86 (.73–1.03) | NAa |
| South | 0.92 (.81–1.05) | NAa |
| Central | 0.97 (.85–1.10) | NAa |
| West | Reference | NAa |
| Modified APACHE III score | ||
| ≤21 | Reference | Reference |
| 22–32 | 1.43 (1.27–1.62) | 1.30 (1.15–1.48) |
| 33–45 | 1.62 (1.37–1.91) | 1.37 (1.15–1.64) |
| >45 | 2.27 (1.76–2.94) | 1.86 (1.41–2.46) |
| Staphylococcus aureus susceptibility | ||
| MSSA | Reference | Reference |
| MRSA | 1.32 (1.18–1.47) | 1.27 (1.13–1.42) |
| Polymicrobial infection | 0.96 (.86–1.07) | NAa |
| Joint | ||
| Knee | 0.78 (.48–1.28) | NAa |
| Hip | 0.77 (.47–1.28) | NAa |
| Timing of PJI from previous joint surgery | ||
| Early (within 90 d) | 0.85 (.74–.97) | NAa |
| Late (after 90 d) | 0.93 (.83–1.06) | NAa |
| Unknown | Reference | NAa |
| Comorbidities | ||
| Congestive heart failure | 1.29 (1.14–1.47) | 1.18 (1.04–1.35) |
| Peripheral vascular disease | 1.20 (1.07–1.35) | 1.22 (1.08–1.37) |
| Hemiplegia | 1.40 (1.13–1.74) | 1.37 (1.09–1.72) |
| Diabetes mellitus | 1.15 (1.03–1.27) | 1.19 (1.06–1.32) |
| Liver disease | 1.18 (1.04–1.34) | 1.15 (1.01–1.32) |
| Solid cancer | 1.15 (1.02–1.31) | 1.19 (1.05–1.34) |
| Peptic ulcer | 1.15 (.96–1.37) | 1.18 (.98–1.42) |
| Myocardial infarction | 1.04 (.89–1.23) | NAa |
| COPD | 0.97 (.88–1.08) | NAa |
| Cerebrovascular disease | 0.93 (.82–1.06) | NAa |
| Autoimmune disease | 0.95 (.80–1.14) | NAa |
| Hematologic malignancy | 1.09 (.82–1.45) | NAa |
| Chronic kidney disease | 1.06 (.94–1.21) | NAa |
Abbreviations: APACHE, Acute Physiology and Chronic Health Evaluation; BMI, body mass index; CI, confidence interval; COPD, chronic obstructive pulmonary disease; HR, hazard ratio; MRSA, methicillin-resistant Staphylococcus aureus; MSSA, methicillin-susceptible Staphylococcus aureus; NA, not applicable; PJI, prosthetic joint infection.
a
Variable was not selected in the final multivariate model.