Selenium supplementation for critically ill adults

Background

Selenium is a trace mineral essential to health and has an important role in immunity, defence against tissue damage and thyroid function. Improving selenium status could help protect against overwhelming tissue damage and infection in critically ill adults.

Objectives

This review assessed the effects of selenium supplementation, including the selenium-containing compound ebselen, on adults recovering from critical illness.

Search strategy

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 3), MEDLINE, EMBASE, CAB NAR, BIOSIS, CINAHL, Current Controlled Trials and reference lists. We contacted investigators and handsearched four journals. The date of the most recent search was August 2007.

Selection criteria

Randomized trials of selenium or ebselen supplementation by any route in adults with critical illness (including patients with burns, head injury, brain haemorrhage, cerebrovascular accident) and after surgery.

Data collection and analysis

Two authors independently extracted data and assessed trial quality. We sought additional information as required from trialists. We undertook pooling of data for outcomes and selected exploratory analyses were undertaken.

Main results

Ten randomized trials involving 1172 participants were included. The quality of trials, as reported, was poor, particularly for allocation concealment. The availability of outcome data was limited and trials involving selenium supplementation were mostly small. Thus the results must be interpreted with caution.

Seven trials of intravenous sodium selenite showed no statistically significant difference in mortality (relative risk (RR) 0.75, 95% confidence interval (CI) 0.53 to 1.06). In general intensive care patients the RR for selenium supplementation was 0.75 (95% CI 0.59 to 0.96). Three trials of ebselen showed no statistically significant difference in mortality (RR 0.83, 95% CI 0.51 to 1.35).

Three trials of intravenous sodium selenite found no statistically significant difference between groups for participants developing infection (RR 1.22, 95% CI 0.67 to 2.23). Three trials of ebselen provided data for participants developing infections (pyrexia, respiratory infections or meningitis), which were not statistically significant (RR 0.60, 95% CI 0.36 to 1.02).

No clear evidence emerged for the benefits of selenium or ebselen supplementation for the outcomes of days on a ventilator, length of intensive care unit stay, length of hospital stay or quality of life.

Authors' conclusions

There is limited evidence to recommend supplementation of critically ill patients with selenium or ebselen. Trials are required which overcome the defects of the reviewed studies, particularly inadequate size and methodology.