| Odds ratio | 95 % CI | P-value |
---|---|---|---|
Age (years) | 0.970 | 0.932–1.010 | 0.140 |
Charlson Comorbidity Index | |||
 0 | 1.00 |  |  |
  ≥ 1 | 2.16 | 0.83–5.64 | 0.116 |
Mean hospital volume (per year) | |||
  ≤ 4 | 1.00 |  |  |
  ≥ 5 | 0.31 | 0.10–0.96 | 0.042 |
Underlying diagnosis | |||
 Osteoarthritis | 1.00 |  |  |
 Rheumatoid arthritis | 1.43 | 0.63–3.24 | 0.393 |
Anesthesia time | |||
  < 200 min | 1.00 |  |  |
  ≥ 200 min | 2.83 | 1.10–7.28 | 0.031 |