Khazdouz et al.

(2018)

Iran

RCT

PEDro=9

N = 100

Population: Zinc supplemented Group (N=50): Mean Age= 32.0±13.8y; Gender: Male=92%, Female=8%; Mean Time Post Injury= within 24 hours; Mean GCS= 7.2±0.6. Control group (N=50): Mean Age= 37.6±17.5y; Gender: Male= 80%, Female=8%; Mean Time Post Injury= within 24 hours; Mean GCS= 7.2±0.7.

Intervention: Patients were randomly assigned to one of two groups. Both groups were fed through a nasogastric tube for 15 days. The zinc supplemented group received 120mg in addition to standard feeding formula. The control group received a placebo in addition to standard feeding formula. Patients were assessed on day 1, 7, 16, and 28 days.

Outcome Measures:  Plasma zinc, copper, and albumin levels, 24-hour urinary zinc excretion, Sequential Organ Failure Assessment (SOFA) were assessed on days 1, 7, and 16. Erythrocyte Sedimentation Rate (ESR), C-Reactive Protein (CRP), and White Blood Cell (WBC) count were assessed on days 1 and 16. Glasgow Outcome Score (GOS) and mortality rate at day 28, and Length of Stay (LOS). GCS was assessed day 1, 7, 16, and 28.

1.        Plasma zinc levels were significantly different between groups at days 7 and 16 (p<0.001) showing the zinc supplemented group had higher levels.

2.        Plasma copper levels were not significantly different at any time points between groups.

3.        Plasma albumin levels were not significantly different at any time points between groups.

4.        24-hour urinary zinc excretion was significantly different between groups at day 16 (p=0.021) showing the zinc supplemented group had higher levels. Not seen at day 7.

5.        SOFA scores were significantly different between groups at day 16 (p=0.022) showing lower scores in the zinc supplemented group. Not seen at day 7.

6.        ESR level was significantly different between groups at day 16 (p<0.001) showing lower levels in the zinc supplemented group. Not seen on day 1.

7.        CRP level was significantly different between groups at day 16 (p<0.001) showing lower levels in the zinc supplemented group. Not seen at day 1.

8.        WBC was significantly different between groups at day 16 (p<0.001) showing lower levels in the zinc supplemented group. Not seen at day 1.

9.        GOS was not significantly different between groups at day 28.

10.     Mortality rate was not significantly different between groups at day 28.

11.     LOS was significantly different between groups (p=0.043) showing lower stay in the zinc supplemented group.

12.     GCS was significantly different between groups at day 16 and day 28 (p=0.007 and p=0.005, respectively) showing higher scores in the zinc supplemented group. Not seen at day 7.

Young et al. (1996)

USA

RCT

PEDro=7

N=68

Population: Head injury; Intervention Group (n=33): Mean Age=34.6yr; Gender: Male=27, Female=6; Mean GCS Score=6.4. Control Group (n=35): Mean Age=35.9yr; Gender: Male=28, Female=7; Mean GCS Score=6.6.

Intervention: Patients were randomly assigned to receive either zinc at a standard level (2.5 mg) or zinc-supplementation (12 mg) for 15 days. After 15 days, oral zinc (168 mg zinc gluconate, 22 mg elemental zinc) or matching placebo tablet were given for a total of 3 mo.

Outcome Measures: Glasgow Coma Scale (GCS), mortality, zinc concentration, serum pre-albumin levels, Retinol-Binding Protein (RBP) concentrations.

1.        There was no significant difference in 1mo mortality rates between groups (p=0.09).

2.        GCS scores of the zinc-supplemented group were greater than the adjusted mean GCS score of the standard group at day 28 (p=0.03).

3.        Mean serum pre-albumin levels and mean RBP concentrations were significantly higher in the zinc-supplementation group at 3wk post injury (p=0.003 and p=0.01, respectively).

4.        The groups were not different in serum zinc concentration, weight, energy expenditure, or total urinary nitrogen excretion after admission.

5.        The mean 24 hr urine zinc levels were significantly greater in the zinc-supplemented group at days 2 (p=0.0001) and 10 (p=0.01).