Effect of the Treatment of Type 2 Diabetes Mellitus on the Development of Cognitive Impairment and Dementia

Summary

A Cochrane review [Abstract] 1 included 4 studies with a total of 16026 subjects. No study reported the incidence of MCI andonly one study reported the incidence of dementia.

• Intensive vs. standard glycaemic control: The data were driven from two studies (n = 13934) with patients at high cardiovascular risk and from the third study (n = 1791), which provided additional data on hypoglycaemic episodes and mortality. One trial (n = 11140) showed that there is probably no difference between treatment groups in the number of participants who decline by at least 3 points on the Mini-Mental State Examination (MMSE) over 5 years (RR 0.98, 95% CI 0.88 to 1.08); or in the incidence of dementia (RR 1.27, 95% CI 0.87 to 1.85). Another study (n = 2794) showed that there was little or no difference in MMSE score after 40 months (MD −0.01, 95% CI −0.18 to 0.16). Participants on the intensive glycaemic control experienced more episodes of severe hypoglycaemia than those on standard treatment (RR 2.18, 95% CI 1.52 to 3.14; 2 studies; n = 12827). The intensity of glycaemic control has little or no effect on all-cause mortality (RR 0.99, 95% CI 0.87 to 1.13; 3 studies; n = 15888).
• Glibenclamide (glyburide) vs. repaglinide: There may be a small advantage of glibenclamide on global cognitive function measured with the MMSE after 12 months (MD −0.90, 95% CI −1.68 to −0.12; one trial, n=156). No data were reported on the incidence of dementia, hypoglycaemic events or all-cause mortality.
• Rosiglitazone plus metformin vs. glibenclamide (glyburide) plus metformin: One study (n=145) reported only cognitive subdomains over 24 weeks and not global cognitive function, incidence of MCI or dementia, hypoglycaemic events or all-cause mortality.