Which can predict memory problems after surgery better; blood sugar levels or memory before surgery?

Postoperative cognitive dysfunction (POCD) occurs relatively frequently after surgery. POCD has been shown to increase the risk of subsequent dementia as well as premature death. However, because of poor characterization of the syndrome and resulting lack of diagnostic criteria, substantial variation exists in reported incidence rates.
Evidence is growing that impaired glucose metabolism and diabetes mellitus are associated with POCD, though the pathophysiology remains largely unknown. Possible mechanisms include autonomic neuropathy, hyperglycaemia induced neurotoxic changes, temporary states of hypoglycemia caused by antihyperglycemic treatment and pre-existing vascular damage.
The primary question is whether patients with impaired glucose metabolism or diabetes mellitus who get POCD have preexisting cognitive dysfunction, or if this results from the procedure.
We hypothesize that POCD depends largely on preoperative cognitive dysfunction and frailty, rather than metabolic impairment alone.
Clarifying the potential role of diabetes, glycemic levels and a history of hypoglycemia is important to be able to provide reliable risk assessment prior to surgery, to tailor post‐surgery clinical care and to inform hypotheses on the mechanisms leading up to POCD. To answer our research question, we aim to perform a prospective cohort study in patients >65 years old undergoing elective surgery.

We hypothesize that POCD depends largely on preoperative cognitive dysfunction and frailty, rather than metabolic impairment alone.

Preoperative: TICS-M and WHODAS 2.0 questionnaire, G8 frail scale, blood tests (incl. HbA1c, Na, K, creatinine)
One month postoperative: TICS-M questionnaire and WHODAS 2.0 questionnaire
Six months postoperative: TICS-M questionnaire and WHODAS 2.0 questionnaire

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