The impact of serum zinc normalization on clinical outcomes in severe burn patients.

INTRODUCTION: Patients with thermal burns become zinc deficient due to exudative losses, increased urinary excretion, and reduction of carrier proteins which results in impaired immunity, wound healing and glucose control. Previous trials have demonstrated improved wound healing utilizing fixed zinc supplementation, but none have assessed the potential benefits associated with normalizing serum zinc concentrations. The objective of this study was to compare the impact of zinc normalization on clinical outcomes in patients with severe thermal burns. METHODS: This retrospective, single-center study of patients with at least 10% total body surface area (TBSA) burn and three serum zinc concentrations compared the ratio of hospital length of stay (LOS) over TBSA burned (LOS/TBSA index) between those with normal (≥60 mcg/mL) and non-normal (<60 mcg/mL) serum zinc concentrations; delineated by the third measurement. Secondary outcomes were time to 90% epithelialization, infection incidence, and percentage of blood glucose values greater than 180 mg/dL. Data are reported as median [25-75% interquartile range] for continuous variables and frequency (percent) for categorical variables. RESULTS: A total of 56 patients were included for evaluation (11 normal and 45 non-normal). Burn size was 20.5% TBSA [11-29] for those with normal zinc and 27.3% [22-36] for non-normal; number of grafts for each group was 1 [0-1] vs 2 [1-3] respectively. LOS/TBSA index did not differ significantly between groups (1.10 normal vs. 1.21 non-normal, unadjusted p = 0.69; p = 0.75 adjusting for number of grafts). Time to 90% epithelialization was reduced in the normal group (27.5 vs. 57 days, p = 0.02), but this did not remain statistically significant after adjustment for %TBSA and number of grafts (p = 0.18). The groups did not differ significantly in incidence of infection or hyperglycemia in either unadjusted or adjusted analyses. CONCLUSIONS: This was the first study, to our knowledge, to assess the clinical impact of normalizing serum zinc levels in patients with severe burns. Our results suggest the normalization of serum zinc levels through individualized zinc supplementation is not associated with improvement in clinical outcomes during hospitalization and therefore fixed-dose zinc supplementation without acquisition of serum zinc measurements should be considered.