Perioperative hyperglycemia is common during cardiac surgery and has been linked to an increased risk of surgical site infections (SSIs). However, the benefits of perioperative tight glucose control (TGC) remain debated, largely due to concerns about hypoglycemia. This systematic review assessed the effects and safety of TGC on SSIs in adults undergoing cardiac surgery.

We searched MEDLINE, Embase, and Cochrane databases for randomized controlled trials (RCTs) comparing TGC (upper blood glucose target ≤150 mg/dL or 8.3 mmol/L) with conventional glucose management in adults undergoing cardiac surgery. The primary outcome was incidence of SSIs. Secondary outcomes included hypoglycemia, length of intensive care unit (ICU) stay, incidence of neurological deficits and all-cause mortality within 30 days after surgery. The certainty of evidence was evaluated using the GRADE approach.

Twenty-six RCTs including 17,990 participants were analyzed. TGC compared with control group was associated with reducing the risk of SSIs (risk ratio [RR]: 0.53; 95 % confidence interval [CI]: 0.42–0.68; I² = 0 %; low certainty evidence), particularly when initiated at the start of surgery (RR: 0.50, 95 %CI: 0.39–0.66, I² = 0; low certainty evidence) but not postoperatively (RR = 0.80, 95 % CI: 0.39–1.66; I² = 0; very low certainty evidence). TGC also shortened ICU stay by 7.03 h compared to the control group (95 % CI: −10.83 to −3.22; very low certainty evidence), though heterogeneity was considerable (I² = 92 %). However, TGC was associated with a higher risk of hypoglycemia (RR: 3.14; 95 % CI: 2.37–4.16; I² = 0; moderate certainty evidence). No significant effects were observed on neurological deficits or all-cause mortality.

This systematic review of the available evidence suggests that perioperative TGC, particularly when initiated at the start of surgery, may reduce the risk of SSIs following cardiac surgery. However, it increases the risk of hypoglycemia and does not significantly impact neurological outcomes and all-cause mortality.