Table 1.
Characteristics of included patients
| Characteristic | All patients (n = 13,254; 100%)a | No pressure injuries (n = 9728; 73.4%)a | Pressure injuries (n = 3526; 26.6%)a | ICU-acquired pressure injuries (n = 2145; 16.2%)a |
|---|---|---|---|---|
| Age, years (M, IQR) | 64 (51–74) | 63 (50–74) | 66 (54–75) | 65 (53–74) |
| Sex (male) | 8184 (61.8) | 5923 (60.9) | 2261 (64.1) | 1414 (65.9) |
| Body Mass Index classb | ||||
| Underweight (< 18.5) | 680 (5.1) | 446 (4.6) | 234 (6.6) | 134 (6.2) |
| Normal weight (18.5–24.9) | 5287 (39.9) | 3944 (40.5) | 1343 (38.1) | 759 (35.4) |
| Pre-obesity (25–29.9) | 4420 (33.3) | 3259 (33.5) | 1161 (32.9) | 733 (34.2) |
| Obesity class I (30–34.9) | 1713 (12.9) | 1259 (12.9) | 454 (12.9) | 305 (14.2) |
| Obesity class II (35–40) | 690 (5.2) | 501 (5.2) | 189 (5.4) | 129 (6) |
| Obesity class III (> 40) | 464 (3.5) | 319 (3.3) | 145 (4.1) | 85 (4) |
| Mechanical ventilation on ICU admission | 7369 (55.6) | 5000 (51.4) | 2369 (67.2) | 595 (27.8) |
| Type of admission | ||||
| Medical | 6501 (49) | 4499 (46.2) | 2002 (56.8) | 1114 (51.9) |
| Elective surgery | 29 (22.5) | 2521 (25.9) | 457 (13) | 288 (13.4) |
| Emergency surgery | 2609 (19.7) | 1866 (19.2) | 743 (21.1) | 522 (24.3) |
| Trauma and burns | 1066 (8.8) | 842 (8.7) | 324 (9.1) | 221 (10.3) |
| Comorbidities | ||||
| Acquired Immune Deficiency Syndrome | 56 (0.4) | 35 (0.4) | 21 (0.6) | 16 (0.7) |
| Chronic Obstructive Pulmonary Disease | 1663 (12.5) | 1058 (10.9) | 605 (17.2) | 368 (17.2) |
| Malignancy | 1509 (11.4) | 1093 (11.2) | 416 (11.8) | 246 (11.5) |
| Cancer, solid tumour | 1089 (8.2) | 812 (8.3) | 277 (7.9) | 167 (7.8) |
| Metastatic cancer | 378 (2.9) | 280 (2.9) | 98 (2.8) | 47 (2.2) |
| Haematologic cancer | 233 (1.8) | 147 (1.5) | 86 (2.4) | 55 (2.6) |
| Immunocompromised | 968 (7.3) | 633 (6.5) | 335 (9.5) | 206 (9.6) |
| Corticosteroid therapy | 449 (3.4) | 271 (2.8) | 178 (5) | 106 (4.9) |
| Immunosuppression | 444 (3.3) | 279 (2.9) | 165 (4.7) | 107 (5) |
| Chemotherapy | 313 (2.4) | 228 (2.3) | 85 (2.4) | 55 (2.6) |
| Cirrhosis | 433 (3.3) | 314 (3.2) | 119 (3.4) | 60 (2.8) |
| Diabetes | 2842 (21.4) | 1913 (19.7) | 929 (26.3) | 534 (24.9) |
| Heart failure | 1752 (13.2) | 1132 (11.6) | 620 (17.6) | 373 (17.4) |
| Impaired mobility | 1680 (12.7) | 1067 (11) | 613 (17.4) | 311 (14.5) |
| Malnutrition | 651 (4.9) | 359 (3.7) | 292 (8.3) | 138 (6.4) |
| Peripheral vascular disease | 662 (5) | 408 (4.2) | 254 (7.2) | 146 (6.8) |
| Renal failure | 1416 (10.7) | 898 (9.2) | 518 (14.7) | 320 (14.9) |
| Simplified Acute Physiology Score II categoryc | ||||
| ≤ 23 | 3473 (26.2) | 2985 (30.7) | 488 (13.8) | 304 (14.2) |
| 24–33 | 3335 (25.2) | 2616 (26.9) | 719 (20.4) | 431 (20.1) |
| 34–44 | 2955 (22.3) | 1973 (20.3) | 982 (27.9) | 595 (27.7) |
| ≥ 45 | 3491 (26.3) | 2154 (22.1) | 1337 (37.9) | 815 (38.0) |
| Braden score categoryd | ||||
| Very high risk (≤ 9) | 1448 (10.9) | 849 (8.8) | 599 (17) | 53 (2.5) |
| High risk (10–12) | 3928 (29.6) | 2491 (25.8) | 1437 (40.8) | 365 (17) |
| Moderate risk (13–14) | 2474 (18.8) | 1743 (18.1) | 731 (20.8) | 463 (21.6) |
| Mild risk (15–18) | 3689 (27.8) | 3039 (31.5) | 650 (18.5) | 878 (41) |
| No risk (19–23) | 1635 (12.3) | 1534 (15.9) | 101 (2.9) | 383 (17.9) |
| Length of stay in ICU prior to study day (M, IQR) | 4 (1–12) | 3 (1–9) | 10 (4–25) | 13 (5–29) |
| Length of stay in ICU (M, IQR) | 11 (4–28) | 8 (3–21) | 22 (10–46) | 27 (13–52) |
| Length of stay from ICU admission to hospital discharge (M, IQR) | 19 (9–40) | 16 (8–33) | 31 (15–57) | 36 (19–62) |
| Length of stay in hospital after study day (M, IQR) | 12 (6–27) | 10 (5–23) | 17 (7–35) | 19 (8–36) |
| Patients still in ICU 3 months after study day | 178 (1.3) | 129 (1.3) | 49 (1.4) | 30 (1.4) |
| Patients still in non-ICU ward 3 months after study day | 781 (5.9) | 531 (5.5) | 250 (7.1) | 171 (8) |
| Deceased during hospital stay | 2929 (22.1) | 1663 (17.1) | 1266 (35.9) | 812 (37.9) |
| 28-days mortality | 1751 (13.2) | 1149 (11.8) | 606 (17.2) | 340 (15.9) |
Results are expressed as number (percentages) if not differently indicated
ICU intensive care unit, M median, IQR interquartile range
aTotals may not sum to 13,254, 9728, 3526 and 2145, respectively, owing to missing values; an overview of the completeness of data is in Online Resource_8
bBody Mass Index is body weight in kilograms divided by body height in meters squared
cRange of possible scores is 0–163; a higher SAPS II score indicates a higher severity of disease and acute illness; scores are categorized according to the sample’s quartiles
dRange of possible scores is 6–23