Summary of baseline characteristics stratified by OSA status
| No OSA (n=38 538) | OSA (n=3228) | P value | |
| Obesity | 7972 (20.7) | 1501 (46.5) | <0.001 |
| ASA status | |||
| I–II | 35 827 (93.0) | 2427 (75.2) | <0.001 |
| III–IV | 2706 (7.0) | 801 (24.8) | |
| Missing | 5 (0.0) | 0 (0.0) | |
| Type of anesthesia | |||
| General | 814 (2.1) | 100 (3.1) | <0.001 |
| Neuraxial | 37 724 (97.9) | 3128 (96.9) | |
| Time period | |||
| 2005–2006 | 2762 (7.2) | 143 (4.4) | <0.001 |
| 2007–2008 | 7010 (18.2) | 491 (15.2) | |
| 2009–2010 | 8388 (21.8) | 704 (21.8) | |
| 2011–2012 | 9796 (25.4) | 830 (25.7) | |
| 2013–2014 | 10 582 (27.5) | 1060 (32.8) | |
| Age | 66.00 (58.00–74.00) | 64.00 (57.00–71.00) | <0.001 |
| Gender | |||
| Female | 23 427 (60.8) | 1182 (36.6) | <0.001 |
| Male | 15 111 (39.2) | 2046 (63.4) | |
| Type of surgery | |||
| THA | 19 690 (51.1) | 1332 (41.3) | <0.001 |
| TKA | 18 848 (48.9) | 1896 (58.7) | |
| Baseline laboratory values | |||
| Hemoglobin | 13.30 (12.40–14.30) | 13.70 (12.70–14.60) | <0.001 |
| Missing | 5526 (14.3) | 464 (14.4) | |
| Creatinine | 0.90 (0.70–1.00) | 0.90 (0.80–1.10) | <0.001 |
| Missing | 5613 (14.6) | 470 (14.6) | |
| INR | 0.99 (0.97–1.03) | 1.00 (0.97–1.03) | <0.001 |
| Missing | 5646 (14.7) | 474 (14.7) | |
| Platelets | 251.00 (212.00–297.00) | 241.00 (201.00–284.00) | <0.001 |
| Missing | 5537 (14.4) | 465 (14.4) | |
| Perioperative benzodiazepines | |||
| No | 2038 (5.3) | 152 (4.7) | <0.001 |
| Yes | 31 170 (80.9) | 2705 (83.8) | |
| Missing | 5330 (13.8) | 371 (11.5) | |
| Perioperative ketamine | |||
| No | 25 361 (65.8) | 2139 (66.3) | <0.001 |
| Yes | 3634 (9.4) | 476 (14.7) | |
| Missing | 9543 (24.8) | 613 (19.0) | |
| Postoperative outcomes | |||
| Cardiac | 855 (2.2) | 76 (2.4) | 0.660 |
| Pulmonary | 839 (2.2) | 113 (3.5) | <0.001 |
| Gastrointestinal | 419 (1.1) | 55 (1.7) | 0.002 |
| Renal/genitourinary | 869 (2.3) | 94 (2.9) | 0.020 |
| Thromboembolic | 327 (0.8) | 30 (0.9) | 0.704 |
| Delirium | 851 (2.2) | 71 (2.2) | 1.000 |
| Prolonged LOS (>4 days) | 7344 (19.1) | 782 (24.2) | <0.001 |
Categorical variables are summarized as frequency (%) and are analyzed using χ2 test. Continuous variables are summarized as median (IQR) and are analyzed using t-test. Missing data are summarized as frequency (%).
ASA, American Society of Anesthesiologists; INR, international normalized ratio; LOS, length of stay; OSA, obstructive sleep apnea; THA, total hip arthroplasty.