Association of Metformin use with risk of dementia in patients with type 2 diabetes: A systematic review and meta-analysis.

AIM

There is ongoing debate concerning the association of metformin with the risk of dementia in type 2 diabetes mellitus (T2DM). This study was conducted to evaluate the impact of metformin therapy on dementia in patients with T2DM.

MATERIALS AND METHODS

PubMed, Embase, Cochrane Library, Web of Science and the ClinicalTrials.gov website were searched until 9 April 2024. Cohort studies investigating the effects of metformin therapy compared with other antidiabetic drugs or no therapy in T2DM were included. The hazard ratio (HR) and the 95% confidence interval (CI) were computed using the random effects model.

RESULTS

Twenty cohort studies (24 individual comparisons) involving 3 463 100 participants were identified. A meta-analysis revealed that people with T2DM who take metformin are linked to a lower incidence of all-cause dementia compared to non-user (n = 17, HR = 0.76, 95% CI = 0.65-0.91, p = 0.002, I = 98.9%) and sulfonylureas (n = 5, HR = 0.88, 95% CI = 0.85-0.90, p < 0.001, I = 9.7%), but not to thiazolidinedione (n = 2, HR = 0.53, 95% CI = 0.08-3.41, p = 0.503, I = 92.7%). Additionally, metformin showed favourable effects in non-specified T2DM (n = 19, HR = 0.75, 95% CI = 0.64-0.89), but not in newly diagnosed T2DM (n = 5, HR = 1.01, 95% CI = 0.81-1.27).

CONCLUSION

Metformin might correlate with a lower dementia incidence in people with T2DM. However, it is crucial to interpret these results with caution considering the high heterogeneity.