Table 1 Characteristics of the randomized placebo-controlled trials included in the meta-analysis.

From: Vitamin D supplementation and the outcomes of critically ill adult patients: a systematic review and meta-analysis of randomized controlled trials

Study, publish year

Study sites

Study duration

No of patients

Study population

Intervention

Amrein et al., 2011

Single center in Austria

2009–2010

25

Adult patients expected to stay in the ICU for 48 h or more, and had a 25-hydroxyvitamin D level ≤ 20 ng/mL

Single enteral dose of vitamin D3 540,000 IUs

Leaf et al., 2014

Two centers in USA

2013

67

ICU adult patients with severe sepsis or septic shock and presence of an arterial or central venous catheter

Single intravenous dose of calcitriol 2 μg

Amrein et al., 2014

Single center in Austria

2012–2015

475

Patients who were 18 years or older expected to stay in the ICU for 48 h or more, and had a 25-hydroxyvitamin D level ≤ 20 ng/mL

Single enteral dose of vitamin D3 540,000 IUs followed by monthly maintenance doses of 90,000 IU for 5 months

Quraishi et al., 2015

Single center in USA

2014

30

Adult patients admitted to medical or surgical ICU and with 24 h of new onset sepsis

Single enteral dose of vitamin D3 200,000 IU or 400,000 IUs

Han et al., 2016

Two centers in USA

NR

30

Adult patients received care in ICU, expected to require MV for ≥ 72 h and expected to survive and remain in ICU for ≥ 96 h

Different vitamin D3 enteral doses divided more than 5 consecutive days (50,000 IU or 100,000 IU daily)

Miroliaee et al., 2017

Two centers in Iran

2014–2015

46

Adult patients who had been diagnosed wtih ventilator-associated pneumonia and 25-hydroxyvitamin D level ≤ 30 ng/mL

300,000 IUs of intramuscular vitamin D

Ginde et al., 2019

44 centers in USA

2017–2018

1,078

Adult patients admitted to ICU and had 25-hydroxyvitamin D level ≤ 20 ng/mL

a single enteral dose of 540,000 IU1

Hasanloei et al., 2019

Single center in Iran

2017–2018

72

Traumatic injury admitted to ICU with a 25(OH)D serum level between 10 and 30 ng/mL

Oral 50,000 IU cholecalciferol daily for 6 days, or one intramuscular injection of 300,000 IU of cholecalciferol

Miri et al., 2019

Single center in Iran

NA

40

Mechanically ventilated patient admitted to ICU

intramuscular injection of 300,000 IU vitamin D

  1. NA not applicable.