Data set characteristics
| Count at ISHPs (% of group) | Count at NHS site (% of group) | Median length of stay (IQR), days, both groups | 28-day readmission proportion (%), both groups* | ||
| Within specialty | All cause | ||||
| Total inpatient operations | 468 259 | 3 203 331 | 2 (0–4) | 2.8 | 5.3 |
| Median age (IQR) | 64 (51–72) | 57 (39–70) | NA | NA | NA |
| Sex | |||||
| Male | 202 080 (43.2) | 1 239 148 (38.7) | 2 (0–3) | 2.5 | 5.2 |
| Female | 266 179 (56.8) | 1 964 183 (61.3) | 2 (0–4) | 3.1 | 5.3 |
| Generic operation type | |||||
| Cholecystectomy | 56 153 (12.0) | 656 976 (20.5) | 1 (0–1) | 5.3 | 7.1 |
| Hip replacement | 142 451 (30.4) | 518 755 (16.2) | 4 (3–6) | 1.8 | 5.5 |
| Hysterectomy | 13 676 (2.9) | 310 517 (9.7) | 3 (2–4) | 5.9 | 8.4 |
| IH repair | 8783 (1.9) | 46 919 (1.5) | 0 (0–1) | 2.8 | 4.6 |
| Knee replacement | 150 834 (32.2) | 554 743 (17.3) | 4 (3–6) | 1.9 | 5.7 |
| Lumbar decompression | 13 770 (2.9) | 59 163 (1.8) | 1 (1–2) | 2.0 | 4.0 |
| Prostate resection | 10 190 (2.2) | 150 664 (4.7) | 2 (2–3) | 4.5 | 8.9 |
| UH repair | 31 270 (6.7) | 177 216 (5.5) | 0 (0–0) | 2.8 | 4.0 |
| VH repair | 6322 (1.4) | 40 759 (1.3) | 0 (0–1) | 4.6 | 6.5 |
| Wisdom tooth | 34 810 (7.4) | 687 619 (21.5) | 0 (0–0) | 0.3 | 1.1 |
| Year of operation | |||||
| 2006 | 2746 (0.6) | 135 542 (4.2) | 3 (0–5) | 2.8 | 5.5 |
| 2007 | 4393 (0.9) | 210 329 (6.6) | 3 (0–5) | 2.7 | 5.2 |
| 2008 | 9332 (2.0) | 221 976 (6.9) | 2 (0–5) | 2.6 | 5.1 |
| 2009 | 13 612 (2.9) | 227 037 (7.1) | 2 (0–5) | 2.7 | 5.3 |
| 2010 | 23 050 (4.9) | 240 486 (7.5) | 2 (0–4) | 2.7 | 5.2 |
| 2011 | 30 373 (6.5) | 243 700 (7.6) | 2 (0–4) | 2.8 | 5.2 |
| 2012 | 33 960 (7.3) | 249 360 (7.8) | 2 (0–4) | 2.8 | 5.2 |
| 2013 | 38 584 (8.2) | 247 253 (7.7) | 1 (0–4) | 2.8 | 4.9 |
| 2014 | 45 340 (9.7) | 259 501 (8.1) | 1 (0–3) | 2.8 | 5.1 |
| 2015 | 48 386 (10.3) | 248 852 (7.8) | 1 (0–3) | 2.7 | 5.1 |
| 2016 | 49 082 (10.5) | 239 920 (7.5) | 1 (0–3) | 2.8 | 5.2 |
| 2017 | 54 137 (11.6) | 237 737 (7.4) | 1 (0–3) | 2.9 | 5.3 |
| 2018 | 56 443 (12.1) | 223 751 (7.0) | 1 (0–3) | 3.1 | 5.7 |
| 2019 | 58 821 (12.6) | 217 887 (6.8) | 1 (0–3) | 3.2 | 5.9 |
| Index of Multiple Deprivation quintile | |||||
| 1 (most deprived) | 58 046 (12.4) | 606 142 (18.9) | 1 (0–3) | 3.4 | 6.0 |
| 2 | 78 162 (16.7) | 646 250 (20.2) | 1 (0–4) | 2.9 | 5.4 |
| 3 | 100 595 (21.5) | 664 635 (20.7) | 2 (0–4) | 2.8 | 5.2 |
| 4 | 113 908 (24.3) | 649 870 (20.3) | 2 (0–4) | 2.7 | 5.1 |
| 5 (least deprived) | 116 154 (24.8) | 607 432 (19.0) | 2 (0–4) | 2.5 | 4.9 |
| Unknown | 1394 (0.3) | 29 002 (0.9) | 3 (0–5) | 1.8 | 3.1 |
| Charlson Comorbidity Index | |||||
| 0 | 358 809 (76.6) | 2 314 090 (72.2) | 1 (0–3) | 2.6 | 4.5 |
| 1–3 | 24 130 (5.2) | 156 869 (4.9) | 3 (1–5) | 3.3 | 6.7 |
| 4+ | 85 320 (18.2) | 732 372 (22.9) | 3 (1–5) | 3.6 | 7.6 |
| Ethnicity | |||||
| White | 348 850 (74.5) | 2 566 935 (88.1) | 2 (0–4) | 3.0 | 5.6 |
| Asian | 8336 (1.8) | 119 653 (3.7) | 1 (0–3) | 3.5 | 6.0 |
| Black | 2669 (0.6) | 71 840 (2.2) | 0 (0–3) | 3.0 | 5.4 |
| Mixed | 1579 (0.3) | 21 203 (0.7) | 0 (0–2) | 2.6 | 4.3 |
| Other/unknown | 106 825 (22.8) | 423 700 (13.2) | 1 (0–3) | 1.7 | 3.4 |
Similar operation types have been grouped together in order to summarise the data.
*The percentage is calculated based on patients discharged alive (and not transferred to another hospital provider) within 60 days of their index admission.
IH, inguinal hernia; ISHP, Independent Sector Healthcare Provider; NA, not applicable; NHS, National Health Service; UH, umbilical hernia; VH, ventral hernia.