Table 1. Descriptive data of the two cohorts.
| Cohort 1 | Cohort 2 | |
|---|---|---|
| N = 364 | N = 332 | |
| Characteristic | ||
| Background data | ||
| Age, median (IQR) | 84 (79–88) | 85 (78–89) |
| Female, n/N (%) | 276/364 (76) | 252/332 (76) |
| Prefracture Barthel Index score, median (IQR) | 19 (16–20) | 18 (14–20) |
| Nottingham EADL, median (IQR) | 39 (17–56) | 30(10–52) |
| Prefracture dementia (consensus diagnosis), n/N (%) | 65/171 (38) | 165/332 (50) |
| IQCODE score, median (IQR) | 3.44 (3.06–4.50) | 3.75 (3.06–4.81) |
| Living in an institution, n/N (%) | 56/364 (15) | 104/332 (31) |
| Injury occurred indoors, n/N (%) | 259/361 (72) | 277/332 (83) |
| Prefracture hypertension, n/N (%) | 121/364 (33) | 136/315 (43) |
| Charlson comorbidity index > 1, n/N (%) | 107/364 (29) | 108/332 (33) |
| Polypharmacy (= 5 or more systemic medications), n/N (%) | 140/364 (39) | 159/332 (48) |
| BMI, median (IQR)b | 22 (20–25) | 24 (21–27) |
| Admission data | ||
| Time admission to surgery, hours, median (IQR) | 18 (9–29) | 24 (16–40) |
| CRP > 10 mg/L, n/N (%) | 129/364 (35) | 130/328 (40) |
| ASA group III, IV or V, n/N (%) | 181/363 (50) | 191/306 (62) |
| Spinal anaesthesia, n/N (%) | 337/362 (93) | 291/315 (92) |
| Surgery started between 5:00 p.m. and 6:30 a.m. | 153/360 (43) | 156/328 (48) |
| Sepsis, n/N (%) | 5/364 (1) | 4/332 (1) |
| Stroke, n/N (%) | 3/364 (1) | 1/332 (0) |
| Delirium any time during hospital stay | 168/364 (46) | 168/327 (51) |
| Preoperative delirium | 50/237 (21) | 99/299 (33) |
| Incident delirium | 68/187 (36) | 56/200 (26) |
IQR = Interquartile range; Nottingham EADL = Nottingham Extended Activities of Daily Living; IQCODE = Informant Questionnaire on Cognitive Decline in the Elderly; BMI = Body Mass Index; CRP = C-reactive protein; ASA = American Society of Anaesthesiologists
Missing data (N) for several variables: Prefracture dementia consensus diagnosis: N = 193, Injury occurred indoors: N = 3, Prefracture hypertension: N = 17, BMI: N = 134, CRP: N = 4, ASA group: N = 27, Spinal anaesthesia: N = 19, Time of surgery: N = 8, Delirium any time: N = 5, Preoperative delirium assessments: N = 160 (127 in cohort 1 and 33 in cohort 2).