Patient characteristics by procedure
| Primary TKR | Primary TKR | Revision TKR | Revision THR | |
| No of study participants | 10 260 | 10 961 | 505 | 633 |
| Age (mean (SD)) | 70.01 (9.24) | 68.93 (10.53) | 69.43 (9.93) | 70.34 (10.91) |
| Gender: male (n (%)) | 4426 (43.1) | 4525 (41.3) | 233 (46.1) | 264 (41.7) |
| Year of surgery (median (IQR)) | 2009 (2006, 2011) | 2008 (2005, 2011) | 2009 (2007, 2011) | 2009 (2006, 2011) |
| Diagnoses recorded in CPRD | ||||
| Rheumatoid arthritis (n (%)) | 851 (8.3) | 639 (5.8) | 65 (12.9) | 92 (14.5) |
| Diagnoses recorded in HES APC | ||||
| Myocardial infarction (n (%)) | 138 (1.3) | 140 (1.3) | 6 (1.2) | 14 (2.2) |
| Congestive cardiac failure (n (%)) | 96 (0.9) | 137 (1.2) | 8 (1.6) | 14 (2.2) |
| Peripheral vascular disease (n (%)) | 101 (1.0) | 102 (0.9) | 10 (2.0) | 8 (1.3) |
| Cerebrovascular disease (n (%)) | 54 (0.5) | 56 (0.5) | 3 (0.6) | 5 (0.8) |
| Dementia (n (%)) | 25 (0.2) | 37 (0.3) | 0 (0.0) | 10 (1.6) |
| Chronic pulmonary disease (n (%)) | 1091 (10.6) | 998 (9.1) | 58 (11.5) | 55 (8.7) |
| Rheumatological disease (n (%)) | 593 (5.8) | 474 (4.3) | 38 (7.5) | 50 (7.9) |
| Liver disease (n (%)) | 20 (0.2) | 22 (0.2) | 0 (0.0) | 5 (0.8) |
| Diabetes mellitus (n (%)) | 991 (9.7) | 755 (6.9) | 56 (11.1) | 45 (7.1) |
| Haemiplegia or paraplegia (n (%)) | 18 (0.2) | 17 (0.2) | 4 (0.8) | 5 (0.8) |
| Renal disease (n (%)) | 202 (2.0) | 235 (2.1) | 11 (2.2) | 20 (3.2) |
| Any malignancy (n (%)) | 78 (0.8) | 97 (0.9) | 7 (1.4) | 9 (1.4) |
| Metastatic solid tumour (n (%)) | 6 (0.1) | 10 (0.1) | 1 (0.2) | 2 (0.3) |
| AIDS HIV infection (n (%)) | 0 (0.0) | 1 (0.0) | 0 (0.0) | 0 (0.0) |
| RCS Charlson score (n (%)) | ||||
| 0 | 7443 (72.5) | 8413 (76.8) | 342 (67.7) | 455 (71.9) |
| 1 | 2302 (22.4) | 2110 (19.3) | 130 (25.7) | 124 (19.6) |
| 2 | 437 (4.3) | 353 (3.2) | 29 (5.7) | 45 (7.1) |
| 3+ | 78 (0.8) | 85 (0.8) | 4 (0.8) | 9 (1.4) |
| IMD quintiles (n (%)) | ||||
| 1 | 2330 (22.7) | 2779 (25.4) | 128 (25.3) | 208 (32.9) |
| 2 | 2487 (24.2) | 2794 (25.5) | 120 (23.8) | 155 (24.5) |
| 3 | 2383 (23.2) | 2479 (22.6) | 117 (23.2) | 127 (20.1) |
| 4 | 1930 (18.8) | 1923 (17.5) | 105 (20.8) | 84 (13.3) |
| 5 | 1121 (10.9) | 980 (8.9) | 35 (6.9) | 59 (9.3) |
| Missing | 9 (0.1) | 6 (0.1) | 0 (0.0) | 0 (0.0) |
| Ethnicity (n (%)) | ||||
| Non-White | 240 (2.3) | 60 (0.5) | 15 (3.0) | 6 (0.9) |
| White | 9073 (88.4) | 9643 (88.0) | 460 (91.1) | 575 (90.8) |
| Missing | 947 (9.2) | 1258 (11.5) | 30 (5.9) | 52 (8.2) |
CPRD, Clinical Practice Research Datalink; HES APC, Hospital Episode Statistics Admitted Patient Care; IMD, Index of Multiple Deprivation; RCS, Royal College of Surgeons; THR, total hip replacement; TKR, total knee replacement.