Perioperative hyperglycemia and neurocognitive outcome after surgery: a systematic review

a B introDUction: Preliminary evidence suggest a possible relationship between perioperative hyperglycemia, postop- erative delirium (PoD) or cognitive dysfunction (PocD). We aim to present the available clinical evidence related to chronic (i.e. diabetes mellitus) or acute perioperative hyperglycemia as risk factors for PoD/PocD. eviDence acQUisition: a literature search of eMBase (via ovid, 1974-present) online medical database and MeDline (via PubMed or ovid, 1946-present) was performed. all types of clinical studies including randomized con- trolled trials, prospective, as well as retrospective cohort studies were screened. clinical studies that reported original information on the relationship between diabetes mellitus (DM) and/or acute perioperative abnormal glucose levels and PoD or PocD were selected. reviews and editorials (i.e. articles not presenting original preclinical or clinical research) were excluded and case-reports were not considered for analysis. eviDence sYntHesis: our search resulted in 2356 papers for screening, from which we selected 29 studies that met our inclusion criteria. DM was investigated in 24 observational papers, acute perioperative hyperglycemia in six obser- vational studies and two randomized controlled trials examined the effect of perioperative glucose lowering on PoD/ PocD. Diabetes was associated with PoD or PocD in 18/24 observational studies and 6/6 of the included observational studies found that perioperative hyperglycemia was associated with PoD/PocD, independent of diabetes. the two ran- domized controlled trials had a different trial design and reported conflicting results. conclUsions: according to the available evidence, DM and acute perioperative hyperglycemia may be associated with an increased risk for PoD/PocD. these conclusions are based mostly on observational studies and deserve more and dedicated research. this systematic review may direct the design of future studies. (Cite this article as: Hermanides J, Qeva e, Preckel B, Bilotta F. Perioperative hyperglycemia and neurocognitive outcome after surgery: a systematic review. Minerva anestesiol 2018;84:1178-88. Doi: 10.23736/s0375-9393.18.12400-X) Key words: Hyperglycemia - cognitive dysfunction - Delirium - Diabetes mellitus - Postoperative complications.