Table 3.
Baseline cognitive impairment or dementia as independent risk factors for delirium
| Study (year) | Population | Cognitive baseline | Delirium measure | Mean age (y) | % delirium | Effect size (adjusted) (95% CI) |
|---|---|---|---|---|---|---|
| Arbabi et al32 | Prospective, observational trial (n = 220) patients | History of dementia | RASS, CAM | 59 | 10% | OR: 10.6 (1.2–93.9) |
| Ahmed and Kuo33 | All geriatric patients, aged 65 years and older, who underwent hip hemiarthroplasty following a hip fracture (n = 13,174) | History of dementia | Chart method | 83 | 30% | OR: 2.6 (2.3–2.9) |
| Jaatinen et al34 | Hip fracture, aged 65 y or more (n = 476) | No known cognitive disorder | CAM | – | 18% | OR: 2.29 (1.39–3.79) |
| O’Regan et al35 | Medical inpatients ≥70 years (n = 555) | History of dementia | Revised Delirium Rating Scale (DRS-R98) | – | 33% | OR: 2.5 (1.0–6.4) |
| Sprung et al36 | Mayo Clinic Study of Aging exposed to anesthesia, age ≥65 y (n = 2014) | MCI/dementia (n = 347) | CAM-ICU | 80 | 3.7% | OR: 2.53 (1.52–4.21) |
| Lewis et al37 | Medical inpatients (Tanzania) age >60 y (n = 494) | Neurocognitive battery, then expert panel for DSM-IV | Neurocognitive battery, then expert panel for DSM-V | 75 | 19% | OR: 3.4 (2.0–6.0) |
| Davis et al38 | Vantaa 85+ cohort, n = 465 | DSM-III-R | By reported history, DSM-III-R criteria | 88 | 81 episodes | OR: 0.95 (0.92–0.99) For every MMSE point lost, the risk of incident delirium increased by 5% |
| Zeng et al39 | Medical inpatients age ≥50 (n = 162) | MMSE ≤ 24 Mini-Cog ≤ 2 AD8 ≥ 2 Dementia = (MC)2 ≥ 2 |
CAM | 69 | 14% | RR: 5.5 (2.7–11.1) by MMSE RR: 2.7 (1.3–5.7) by Mini-Cog RR: 2.4 (1.1–5.1) by AD8 RR: 2.5 (1.2–5.5) by dementia = (MC)2 |
| Kennedy et al40 | Emergency department, age ≥ 65 y (n = 700) | Documented dementia by chart | Prevalent delirium by CAM | 77 | 9% | OR: 4.3 (2.2–8.5) |
| Koster et al41 | Elective cardiac surgery, age ≥ 70 y (n = 300) | MMSE < 23 | DOSS | 74 | 17% | OR: 4.5 (1.9–13) |
| Moerman et al42 | Acute hip fracture, age ≥ 65 y (n = 378) | Clinical diagnosis of dementia | Prevalent delirium by DSM-IV | 84 | 27% | OR: 2.8 (1.7–4.6) |
| Bo et al43 | Patients age ≥ 70 years admitted to medical or geriatric ward (n = 252) | SPMSQ for the presence and severity of cognitive impairment | Incident delirium by CAM | 82 | 11% | RR: 2.1 (1.6–2.6) |
| Rudolph et al44 | Planned cardiac surgery, age ≥60 y (development n = 122; validation = 109) | Preoperative MMSE ≤ 23 | Incident delirium by CAM | 75 | 44% | RR: 1.3 (1.0–1.7) |
| Kalisvaart et al45 | Elective hip surgery, age ≥ 70 y (n = 603) | Preoperative MMSE <24 | Postoperative delirium by DSM-IV and CAM | 78 | 12% | RR: 5.5 (3.6–8.6) |
| Wilson et al46 | Patients aged ≥ 75 y admitted to an acute medical ward (n = 100) | IQCODE to establish the presence of cognitive change over time | Incident delirium by DSM-III | 85 | 12% | OR: 3.2 (1.2–9.0) |
| O’Keeffe et al47 | Acute medical admissions to geriatric medicine unit (n = 225) | Clinical diagnosis of dementia or BDRS ≥4 | Incident delirium by DSM-III | 82 | 28% | OR: 4.8 (2.0–11.6) |
| Marcantonio et al48 | Elective surgical admissions, age ≥ 50 y (n = 1,341) | TICS <30 | Postoperative delirium by CAM | 68 | 9% | OR: 4.2 (2.4–7.3) |
| Pompei et al49 | Acute hospital medical and surgical admissions, age ≥ 65 y with no delirium (development n = 432; validation n = 323) | MMSE < 24 (education adjusted) | Incident delirium by DSM-III-R | 74 | 15% | OR: 3.6 (2.1–6.2) |
| Inouye et al50 | Acute hospital medical admissions, age ≥ 70 y with no dementia or delirium (development n = 107; validation n = 174) | MMSE < 24 on admission | Incident delirium by CAM | 79 | 25% | RR: 2.8 (1.2–6.7) |
Abbreviations: BDRS, Blessed Dementia Rating Scale; CAM, Confusion Assessment Method; DOSS, Delirium Observation Screening Scale; IQCODE, Informant Questionnaire for Cognitive Decline in the Elderly; MMSE, Mini-Mental State Examination; OR, odds ratio; RR, relative risk; SPMSQ, Short Portable Mental Status Questionnaire; TICS, telephone interview for cognitive status.