Introduction: Although experimental studies strongly sup- port the cardioprotective effects of glucose—insulin—potas- sium (GIK) infusion, clinical trials have yielded mixed results due to the heterogeneity of patient populations as well as vary- ing GIK administration patterns. An updated systematic review and meta-analysis were conducted to assess the impact of GIK treatment on postoperative complications in patients undergoing on- or off-pump cardiac surgery.

Methods: We searched MEDLINE, Embase and the Cochrane Central Register without language restrictions for studies from inception to March, 2020. We included randomized controlled trials that compared GIK infusion as cardioprotective measure to conventional treatment or placebo in adults undergoing on- or off-pump cardiac surgery. Postoperative myocardial infarct (PMI) was the main study endpoint; secondary outcomes were in-hospital mortality, postoperative complications, as well as duration of mechanical ventilation, intensive care stay and hos- pital stay. Postoperative glycemia and cardiac index were also examined. The study was registered with PROSPERO (N˚ CRD42019117728). We computed risk ratios (RR) or mean dif- ferences (MD) with 95% confidence intervals (CI) and hetero- geneity was estimated using I2 statistic. Results: From 47 studies, 5’872 participants were pooled for meta-analysis. The incidence of PMI was 5.9% and 8.3% in the GIK and Control groups, respectively (n = 20, RR [95% CI] = 0.83 [0.65 to 1.04] I2 = 0). Compared to control treat- ment, GIK infusion was associated with lower hospital mortal- ity (n = 19, RR [95%CI] = 0.64 [0.43 to 0.97], I2 = 0), reduced acute kidney injury (n = 6, RR [95%CI] = 0.59 [0.4 to 0.87, I 2 = 0), fewer atrial fibrillation (n = 23, RR [95%CI] = 0.75 [0.6 to 0.94], I 2 = 0.58), as well as a shorter duration of mechanical ventilation (n = 14, MD [95%CI] = -1.77 [-3.04 to -0.49] hours, I 2 = 0.96), shorter stay in intensive care (n = 20, MD [95%CI] = -5.39 [-9.34 to -1.44] hours, I2 = 0.99) and faster hospital discharge (n = 19, MD [95%CI] = -0.84 [-1.6 to -0.08] days, I 2 = 0.95)

Discussion: A recent systematic review and meta-analysis restricted to part of the literature published on the topic since 2000 concluded to a strong effect of GIK on PMI [1]. While the analysis of our augmented corpus of literature did not find any such association in patients undergoing cardiac surgery, perioperative administration of GIK was associated with improved postoperative clinical outcomes as reflected by lower in-hospital mortality and morbidity as well as lesser uti- lization of hospital resources. Further clinical studies are war- ranted to ascertain the effectiveness of GIK in minimizing myocardial injuries and to explore the specific dosage and tim- ing of GIK infusion.