Thirty-one RCTs were included in the review (n=1,974 patients). Trial sample sizes were generally small: four trials had a sample size of more than 100, 15 trials had a sample size between 31 and 100 patients and 12 trials had a sample size of 30 patients or less. Trial quality was variable: five trials scored 5 out of 5, 10 scored 4, 12 scored 3 and four scored 2.
Compared with placebo, there was no statistically significant difference with steroids in terms of mortality, re-exploration, postoperative infections, sternal wound infections and ventilation length. Steroids offered a statistically significantly reduced risk of atrial fibrillation (OR 0.56, 95% CI 0.44 to 0.72; I2=0%; 15 RCTs) and a statistically significantly reduced blood loss (MD -204.2mL, 95% CI -287.4 to -121, I2=0%; seven RCTs). Steroids also offered a statistically significantly shorter length of intensive care unit stay (MD -6.7 hours, 95% CI -10.5 to -2.8, I2=89%; 17 RCTs) and a shorter overall stay (-0.8 days, 95% CI -1.4 to -0.2, I2=46%; 16 RCTs).
Subgroup analysis indicated differences in certain outcomes between methotrexate and dexamethasone and between diabetic and non-diabetic patients.