Table 1 Analyzed randomized controlled trials: study population, type of intervention, methodological scoring

Amrein et al. 2011[30]

25

Mixed ICU patients, expected LOS > 48 h

25-hydroxyvitamin D ≤ 20 ng/ml

Single dose of 540 000 IU NG

11

1

Amrein et al. 2014[7]

492

Medical and surgical ICU patients, expected LOS > 48 h

25-hydroxyvitamin D ≤ 20 ng/ml

Dose of 540 000 IU NG. 28 days after first dose, 5 monthly maintenance doses of 90 000 IU

12

1

Leaf et al. 2014[31]

67

ICU patients with severe sepsis/septic shock

Mixed

2 µg calcitriol, single dose IV 2ug

12

1

Quraishi et al. 2015[21]

30

ICU patients with sepsis

Mixed

Single dose of 200 000 IU or 400 000 IU

12

1

Han et al. 2016 [19]

31

Mixed ICU patients receiving EN, expected LOS 96 h

Mixed

50 000 IU daily for 5 days or 100 000 IU daily for 5 days

8

1

Ding et al. 2017 [32]

57

Septic patients with ICU stay > 48 h

25-hydroxyvitamin D < 30 ug/mL

Single dose of 300,000 IU IM

7

2

Miroliaee et al. 2018[33]

51

Mechanically ventilated ICU patients with pneumonia

25-hydroxyvitamin D < 30 ng/ml

Single dose of 300,000 IU IM

6

2

Ginde et al. 2019[8]

1360

ICU patients with > 1 risk factors for death or lung injury

25-hydroxy vitamin D < 20 ng/ml

Single dose of 540 000 IU via NG

9

2

Hasanloei et al. 2019[20]

72

Mechanically ventilated (> 48 h) trauma ICU patients with LOS ≥ 7d

25-hydroxy vitamin D 10–30 ng/ml

(1) 50 000 IU daily for five days via NG

(2) Single dose of 300,000 IU IM

5

2

Miri et al. 2019 [35]

44

Mechanically ventilated ICU patients

"Vitamin D deficient"

Single dose of 300,000 IU IM

5

2

Yousefian et al. 2019 [34]

66

Mechanically ventilated stroke patients

25-hydroxy vitamin D < 20 ng/ml

300,000 IU IM up to 3 times per week

7

2

Ingels et al. 2020 [29]

24

ICU patients, expected LOS > 10d

25-hydroxy vitamin D < 10 ng/ml

200 µg calcidiol loading dose on admission followed by 15 µg daily for 10 days

7

2

Karsy et al. 2020 [36]

274

Neurocritical care patients

25-hydroxy vitamin D < 20 ng/ml

Single dose of 540 000 IU

13

1

Sharma et al. 2020 [37]

35

Mechanically ventilated patients with traumatic brain injury

"Vitamin D deficient"

Single dose of 120 000 IU via feeding tube

8

1

Sistanizad et al. 2021 [9]

30

Mechanically ventilated ICU patients surviving the first 72 h

25-hydroxy vitamin D < 10 ng/ml

300,000 IU IM up to 3 times per wk

4

2

Bhattacharyya et al. 2021 [28]

126

Sepsis patients expected to survive > 96 h with EN access

Mixed

Single dose of 540,000 IU dissolved in 45 ml of milk

11

2