Table 1 Main characteristics included in the meta-analysis
First author/Year of publication (reference) | Amrein et al ./2014 [22] | Aygencel et al ./2013 [19] | Hu et al ./2013 [18] | Nair et al ./2012 [21] | Higgins et al ./2012 [20] | Venkatram et al ./2011 [8] | Braun et al ./2011 [17] |
|---|---|---|---|---|---|---|---|
Study design | Single-center, retrospective | Single-center, prospective | Single-center, prospective | Multi-center, prospective | Multi-center, prospective | Single-center, retrospective | Multi-center, retrospective |
Country | Austria | Turkey | China | Australia | Canada | USA | USA |
Patients | Neurologic (30.2%), cardiac surgery (15.0%), respiratory disease (8.1%), trauma (5.8%), brain surgery (5.0%), infectious diseases, including sepsis at admission (4.4%) | Respiratory insufficiency (45%), organ dysfunctions (44%), invasive mechanical ventilation (44%), sepsis/septic shock (35.8%), renal replacement therapy (34%), nosocomial infection (35%) | Severe pneumonia with respiratory failure (47.2%), acute exacerbations of chronic obstructive pulmonary disease (19%), intra-abdominal infection (15.3%), mechanical ventilation (85.6%) | Cardiac (30%), infection/sepsis (26%), heart/lung/bone marrow transplant (21%), trauma (9%), metabolic (7%), neurological (7%) | Cardiovascular (14%), respiratory (29%), neurological (7%), metabolic (7%), gastrointestinal (3%), sepsis (5%), postoperative (35%) | Cardiac (4.8%), gastrointestinal (10.7%), metabolic (11.4%), neurological (12.5%), obstructive airway disease (13.7%), pulmonary (18.3%), others (10.9%), renal (5%), sepsis/septic shock (12.3%) | Medical (58.3%) Surgical (41.7%) |
Patients, n | 655 | 201 | 216 | 100 | 196 | 437 | 2,399 |
Case patients, n (%) | 394 (60.2%) | 139 (69.2%) | 95 (44.0%) | 24 (24.0%) | 50 (25.5%) | 340 (77.8%) | 637 (26.6%) |
Male patients, n (%) | 412 (62.9%) | 113 (56.0%) | 120 (55.6%) | 65 (65.0%) | 121 (62.0%) | 208 (47.5%) | 1,030 (43.0%) |
Age, y, mean | 65 (22)a | 66 (21)a | 64 (25)a | 52 ± 17b | 64 ± 14b | 56.6 ± 17.1b | 64.9 ± 16.6b |
Severity of illness | 26 (16)a (SAPS II) | 23(11)a (APACHE II) | 21(8)a (APACHE II) | 21 ± 8b (APACHE II) | 20.2 ± 7.8b (APACHE II) | 67.0 ± 27.5b (APACHE IV) | / |
Definition of Vitamin D deficiency, insufficiency and sufficiency | Deficient (<20 ng/ml), insufficient (≥20 and <30 ng/ml), normal (≥30 ng/ml) | Insufficient (<20 ng/ml), sufficient (≥20 ng/ml) | Deficient (<20 ng/ml), insufficient (≥20 and <30 ng/ml), sufficient (≥30 ng/ml) | Deficient (<10 ng/ml), insufficient(10 to 20 ng/ml), sufficient(>20 ng/ml) | Deficient (≤12 ng/ml), insufficient (>12 to ≤24 ng/ml), sufficient (>24 ng/ml) | deficient (<20 ng/ml), insufficient (≥20 and <30 ng/ml), sufficient (≥30 ng/ml) | deficient(≤15 ng/mL, insufficient (16 to 29 ng/mL, sufficient (≥30 ng/ mL) |
Major clinical outcomes | ICU and hospital mortality, ICU and hospital LOS | ICU mortality | Hospital mortality | Hospital mortality, ICU and hospital LOS | Hospital mortality, time-to-alive ICU discharge | Hospital mortality, hospital LOS | 30-day, 90-day, 365-day, and in-hospital morality |
Quality score c | 7 | 6 | 6 | 7 | 7 | 6 | 7 |