Table 2.
Characteristics of intensive care unit admissions contributed by participants eligible for the secondary outcomes according to pre-ICU cognitive status
| Characteristic | Incident NH Admission (N = 267)* |
All-Cause Mortality (N = 391)† |
||||
|---|---|---|---|---|---|---|
| Cognitively Intact (n = 97) | Minimal Impairment (n = 119) | Moderate Impairment (n = 51) | Cognitively Intact (n = 127) | Minimal Impairment (n = 172) | Moderate Impairment (n = 92) | |
| Age, yr | 82.3 (±4.9) | 83.5 (±5.5) | 85.8 (±5.5) | 82.7 (±4.9) | 84.5 (±5.6) | 86.5 (±5.5) |
| Female sex | 53 (54.6) | 77 (64.7) | 28 (54.9) | 71 (55.9) | 107 (62.2) | 53 (57.6) |
| Non-Hispanic white | 91 (93.8) | 99 (83.2) | 45 (88.2) | 119 (93.7) | 148 (86.1) | 76 (82.6) |
| Education, yr | 13.1 (±2.5) | 11.7 (±3.0) | 10.7 (±2.9) | 13.1 (±2.6) | 11.8 (±3.0) | 10.5 (±3.1) |
| Cognitive function by MMSE score‡ | 28.9 (0.8) | 25.8 (±1.0) | 20.7 (±3.3) | 28.9 (0.7) | 25.8 (±1.1) | 18.5 (±5.0) |
| Chronic conditions§ | 2.4 (±1.3) | 2.5 (±1.3) | 2.5 (±1.1) | 2.4 (±1.3) | 2.6 (±1.3) | 2.5 (±1.3) |
| Pre-ICU disability|| | 2.9 (±2.9) | 4.7 (±3.4) | 6.5 (±3.9) | 4.1 (±3.7) | 6.0 (±4.1) | 8.7 (±4.1) |
| Physical capabilities¶ | 6.4 (±3.1) | 5.6 (±2.7) | 4.4 (±2.7) | 5.8 (±3.2)) | 5.1 (±2.9) | 3.1 (±2.8) |
| Nursing home resident in the month before ICU admission | NA | NA | NA | 11 (8.7) | 33 (19.2) | 27 (29.4) |
| ICU length of stay** | 3.5 (±5.8) | 3.1 (±4.9) | 2.7 (±2.1) | 4.1 (±6.4) | 3.9 (±5.7) | 3.2 (±3.0) |
| Use of mechanical ventilation†† | 14 (14.4) | 16 (13.6) | 4 (7.8) | 28 (22.1) | 42 (24.7) | 23 (25.0) |
| Shock†† | 6 (6.2) | 3 (2.5) | 4 (7.8) | 15 (11.8) | 15 (8.7) | 12 (13.0) |
Definition of abbreviations: ICU = intensive care unit; MMSE = Mini-Mental State Examination; NA = not applicable; NH = nursing home.
The 267 ICU admissions were contributed by 216 participants. Only ICU admissions where the participant was community-dwelling before hospital admission and survived to hospital discharge were eligible for the outcome of incident nursing home admission.
The 391 ICU admissions were contributed by 303 participants. Because the ICU admission date was not available in Medicare claims, the hospital admission date was used as a proxy.
Measured with the Folstein Mini-Mental State Exam (MMSE) (20): Scores range from 0 to 30, with higher scores representing better cognitive function. Moderate impairment, minimal impairment, and cognitively intact were defined as MMSE scores of less than 24, 24–27, and 28–30, respectively.
Of a possible nine: hypertension, myocardial infarction, heart failure, stroke, diabetes mellitus, arthritis, hip fracture, chronic lung disease, and cancer (other than minor skin cancers).
From the month before ICU admission, assessed in each of 13 functional activities: four activities of daily living (bathing, dressing, walking, and transferring), five instrumental activities (shopping, housework, meal preparation, taking medications, and managing finances), and four mobility activities (walk a quarter-mile, climb a flight of stairs, lift or carry 10 pounds, and drive in the past month).
Short Physical Performance Battery (SPPB) (24): Scores range from 0 to 12, with higher scores indicating better performance on three objectively measured tasks (gait speed, chair stands, and balance), as described in the text.
When data were available from Medicare claims, ICU length of stay was based on the number of days billed in a critical care unit. For participants in managed Medicare, ICU length of stay was abstracted from the medical record.
Ascertained using ICD-9 codes and chart review, as described in Methods in the online supplement.