Table 2.
Comparison of the 20 cases and 40 controls in univariate analysis with conditional logistic regression
| Cases (n = 20) | Controls (n = 40) | P | |
|---|---|---|---|
| Female, n | 19 | 34 | 0.27 |
| No-low/moderate-high rheumatic disorder activity, n | 11/7 | 20/20 | 0.67 |
| TJA surgery on affected or matched joint within the last year, n | 8 | 5 | 0.03† |
| - of which primary TJA, n/TJA revision, n | 5/3 | 3/2 | |
| - after TNFα-blockers introduction | 6 of 8 | 5 of 5 | |
| - after TNFα-blocker withdrawal ≥5 half-lives | 1 of 6 | 4 of 5 | 0.08 |
| Previous TJA infection, n | 3 | 0 | 0.08 |
| - of which same TJA involved, n | 2 | - | - |
| Main comorbidities, n | |||
| - Diabetes mellitus | 2 | 1 | 0.26 |
| - Bronchiectasis | 0 | 1 | 0.99 |
| - Cirrhosis | 0 | 0 | 1 |
| - Cancer/hemopathy | 0 | 2 | 0.99 |
| - HIV | 0 | 0 | 1 |
| - Chronic renal failure | 1 | 2 | 1 |
| - Hypogammaglobulinemia | 1 | 1 | 0.88 |
| Current TNFα-blocker: | |||
| - Infliximab/etanercept/adalimumab, n | 7/5/8 | 13/15/12 | 0.70 |
| - Duration of exposition to the current TNFα- | 26.0 ± 24.1 | 39.0 ± 24.6 | 0.06 |
| blocker (months) * | |||
| Number of prior TNFα-blockers * | 0.5 ± 0.7 | 0.6 ± 0.7 | 0.69 |
| Total duration of exposition to any TNFα-blockers (months) * | 32.0 ± 25.6 | 48.6 ± 25.2 | 0.07 |
| Oral intake of steroids * (mg/d) | 9.5 ± 7.3 | 5.3 ± 3.9 | 0.02† |
| Oral intake of steroids ≥10 mg/d, n | 7 | 7 | 0.06 |
| Intravenous infusion of steroids last year, n | 2 | 1 | 0.75 |
| Current DMARDs, n | |||
| - Methotrexate | 14 | 26 | 0.71 |
| - Leflunomide | 1 | 5 | 0.99 |
| - Azathioprine | 0 | 2 | 0.40 |
* mean ± standard deviation; † Results achieving a P value < 0.05 were considered as statistically significant.
DMARDs, disease-modifying anti-rheumatic drugs; TJA, total joint arthroplasty; TNF, tumor necrosis factor.