Table 1.
Study and Patient Characteristics.
| Characteristic | Development Cohort, N = 212 | External Validation Cohort, N = 349 | P Value |
|---|---|---|---|
| Data collection period | January 2011 to December 2012 | February 2014 to December 2015 | |
| Study design | Prospective observational cohort | Prospective observational cohort | |
| Setting | Mixed medical-surgical ICU of 1 academic medical center in the Netherlands | Mixed medical-surgical ICUs of 5 hospitals in the Netherlands | |
| Inclusion criteria | Consecutive, newly admitted ICU patients mechanically ventilated for ≥2 days | Consecutive, newly admitted ICU patients mechanically ventilated at 48 hours after ICU admission | |
| Outcome | Presence of ICU-AW | Presence of ICU-AW | |
| Reference standard | Average MRC score<4 | Average MRC score < 4 | |
| Incidence of ICU-AW, n (%) | 103 (49) | 190 (55) | .208 |
| Age, mean (SD) | 61 (16) | 63 (14) | .050 |
| Females, n (%) | 92 (43) | 136 (39) | .347 |
| Reason for admission | |||
| Planned surgical, n (%) | 44 (21) | 72 (21) | .994 |
| Emergency surgical, n (%) | 49 (23) | 85 (24) | |
| Medical, n (%) | 119 (56) | 192 (55) | |
| APACHE IV score, mean (SD) | 81 (28), 3 missing | 79 (27), 16 missing | .272 |
| Maximal SOFA score in first 2 days, mean (SD) | 10 (3) | 9 (3), 12 missing | .013 |
| Average MRC score, median (IQR) | 4.0 (2.6-4.8) | 3.8 (3.2-4.5) | .834 |
| Day of MRC assessment after ICU admission, median (IQR) | 8 (6-12) | 6 (4-10) | <.001 |
| Days with MV, median days (IQR) | 8 (4-16) | 6 (4-11) | .001 |
| LOS ICU, median days (IQR) | 10 (7-8) | 9 (6-17) | .107 |
| ICU mortality, n (%) | 21 (10) | 25 (7) | .269 |
Abbreviations: APACHE IV: Acute Physiology and Chronic Health Evaluation IV; ICU-AW, intensive care unit–acquired weakness; IQR, interquartile range; LOS ICU, length of stay in the intensive care unit; MRC, Medical Research Council; MV, mechanical ventilation; SD, standard deviation; SOFA, Sequential Organ Failure Assessment.