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Table 1 Demographic, clinical characteristics, baseline bone turnover markers, biochemistry, and outcomes by bone mineral density assessments at 2-year follow-up

From: The association of time and medications with changes in bone mineral density in the 2 years after critical illness

Variable All (n = 92) Completed three BMD assessments (n = 48) Completed one to two BMD assessments (n = 44) p value
Age (yrs) 63.4 (±14.7) 65.8 (±11.4) 60.8 (±17.4) 0.1
BMI 27.1 (±5.1) 27.2 (4.4) 27.1 (5.8) 0.9
Women 44 (47.8) 22 (45.8) 22 (50.0) 0.8
Any osteoporosis risk factor 40 (43.5) 15 (31.3) 25 (56.8) 0.02
Co-morbidity
 Renal 7 (7.6) 4 (8.3) 3 (6.8) 1.0
 Cardiovascular 40 (43.5) 22 (45.8) 18 (40.9) 0.7
 Respiratory 22 (23.9) 8 (16.7) 14 (31.8) 0.1
APACHE III score 74.4 (±29.5) 76.3 (±29.3) 72.4 (±30.0) 0.5
ICU admission category
 Medical 54 (58.7) 26 (54.2) 28 (63.6)  
 Cardiothoracic surgery 16 (17.4) 10 (20.8) 6 (13.6)  
 General surgery 22 (23.9) 12 (25.0) 10 (22.7)  
ICU biochemistry and biomarkers
 Albumin (g/L) 23.9 (±5.8) 23.6 (±5.9) 24.1 (±5.7) 0.6
 Calcium adj (mmol/L) 1.99 (±0.33) 2.01 (±0.32) 1.96 (±0.33) 0.5
 Creatinine (umol/L) 116 [85, 178] 125 [85, 175] 109 [89, 196] 0.7
 Vitamin D (nmol/L) 44.2 (±20.2) 43.4 (±20.0) 45.1 (±20.7) 0.7
 Phosphate (mmol/L) 0.70 [0.52, 1.00] 0.67 [0.49, 1.04] 0.72 [0.52, 0.96] 0.7
 PTH (pmol/L) 9.29 (±7.51) 9.88 (±7.94) 8.65 (±7.05) 0.4
 CTX (ng/L) 581 [400, 851] 581 [386, 884] 581 [414, 837] 1.0
 P1NP (ug/L) 31.5 [22.0, 60.0] 30.5 [22.0, 46.0] 32.5 [22.5, 87.0] 0.2
Hospital interventions/outcomes
 Ventilation duration (hrs) 86.0 [47.4, 146.0] 80.4 [43.9, 118.0] 91.9 [52.3, 215.0] 0.1
 Glucocorticoid 29 (31.5) 16 (33.3) 13 (29.5) 0.8
 CRRT 15 (16.3) 6 (12.5) 9 (20.5) 0.3
 ICU LOS (days) 6 [4, 9] 7 [4, 8] 6 [4, 11] 0.9
 Hospital LOS (days) 16 [11, 30] 15 [11, 28] 17 [10, 32] 0.7
Baseline BMD (post-ICU discharge)
 ICU admit to BMD (days) 33 [13,58] 36 [14, 63] 33 [12,56]  
 T-score femur -0.8 (±1.5) -1.0 (±1.4) -0.7 (±1.5) 0.3
 Absolute femur (g/cm3) 0.956 (±0.197) 0.941 (±0.183) 0.974 (±0.212) 0.4
 T-score AP spine 0.1 [-1.4, 1.0] -0.1 [-1.6, 0.8] 0.1 [-1.3, 1.2] 0.4
 Absolute AP spine (g/cm3) 1.207 (±0.242) 1.200 (±0.228) 1.210 (±0.261) 0.7
Mortality
 1-year 8 (8.7) 0 (0) 8 (18.2)  
 2-year 10 (10.9) 0 (0) 10 (22.7)  
  1. Data are shown as mean (±standard deviation), median [interquartile range] or number (%). Complete BMD follow-up defined as all three post-ICU measurements performed during the 2-year period. Incomplete BMD follow-up defined as one or two post-ICU measurements performed. Reference ranges: vitamin D (<25 nmol/L = deficient, 25–50 nmol/L insufficient, >50 nmol/L sufficient), PTH (range 1.6–6.9 pmol)
  2. Abbreviations: BMD bone mineral density, BMI body mass index, APACHE Acute Physiology and Chronic Health Evaluation, ICU intensive care unit, PTH parathyroid hormone, CTX collagen type 1 cross-linked c-telopeptide, P1NP type 1 N-terminal procollagen, CRRT continuous renal replacement therapy, LOS length of stay, AP anterioposterior