China: Findings from a recent meta-analysis showed that metformin use, especially long-term use is tied to a lower risk of neurodegenerative disease (ND) in diabetes patients. However, the researchers add, "owing to a substantial heterogeneity among studies, there is a need for high-quality randomized controlled trials to confirm the finding."
There has always been a controversy on the association between metformin use and neurodegenerative disease onset. To clarify the same, Zubing Mei, Anorectal Disease Institute of Shuguang Hospital, Shanghai, China, and colleagues aimed to determine the relationship between metformin use and ND risk based on data from population-based cohort studies in a systematic review and meta-analysis published in the journal Diabetic Medicine.

For this purpose, the researchers systematically searched articles in PubMed, EMBASE, and Cochrane Library databases. Using a random-effects model, pooled relative risks (RRs) were obtained. In order to identify the sources of heterogeneity and strengthen the results, subgroup analyses, sensitivity analyses, and meta-regression were performed.
Twelve population-based cohort studies consisting of 194,792 participants (94,462 metformin users and 100,330 metformin non-users) were eligible to be included in the meta-analysis.
Based on the study, the researchers found the following:
The pooled RR of NDs reached 0.77 when comparing metformin users with non-users.
The effects were more prominent in long-term metformin users (≥4 years) (RR 0.29) and studies from Asian countries (RR 0.69).
The effect estimates were stable when stratified by subtypes of NDs, study designs, and control definitions.
Meta-regression did not identify the coefficients as the sources of heterogeneity.
To conclude, this systematic review and meta-analysis found that the use of metformin, particularly long-term use is associated with a lower risk of ND. However, because of substantial heterogeneity among studies, there is still a need for high-quality randomized controlled trials to confirm this finding.
Reference:
The study titled, "Metformin and the risk of neurodegenerative diseases in patients with diabetes: A meta-analysis of population-based cohort studies," was published in the journal Diabetic Medicine.
DOI: https://doi.org/10.1111/dme.14821
KEYWORDS: metformin, neurodegenerative diseases, diabetes, Zubing Mei, diabetes medications, type 2 diabetes