Twenty-three trials (2,820 patients, range 16 to 1,001) were included. Reported follow-up durations ranged from seven days to three months. Overall, the evidence was considered at high risk of bias due to a lack of information about methods of randomisation (11 out of 23 trials) and a lack of uniform and explicit definitions of infections. Few studies (five out of 23) reported that outcome assessors were appropriately blinded. The only study on patients with cardiac arrest was generally considered at low risk of bias. Other results of the quality assessment were reported.
Overall incidence of infections was higher in patients treated with hypothermia compared with control but the difference was not statistically significant (rate ratio 1.21, 95% CI 0.95 to 1.54; 23 trials).
Patients who underwent therapeutic hypothermia were at higher risk of pneumonia (risk ratio 1.44, 95% CI 1.10 to 1.90; 16 trials) and sepsis (risk ratio 1.80, 95% CI 1.04 to 3.10; six trials) compared to control. There was no statistically significant difference between intervention and control in risk of urinary tract infection. There was no evidence of significant heterogeneity across the studies (Ι²≤33%).
The one study that included patients with cardiac arrest reported an increased risk of infection in patients treated with hypothermia but the difference was not statistically significant (rate ratio 1.40, 95% CI 0.97 to 2.02). Results of other subgroup analyses were reported.