Is metformin the only culprit for cognitive impairment in diabetes?

Background As diabetic patients conventionally are on a long-term
prescription for metformin, it is important to identify any increase in
their risk for developing cognitive disorders. Hence, an attempt was made
here to study cognitive impairment by using the Montreal Cognitive
Assessment test (MoCA) as a possible predictor of development of cognitive
impairment in type 2 diabetics on metformin therapy. Methods 400 Type 2
diabetics on metformin-containing anti-diabetic regimen were enrolled and
data recorded. A cognitive test, MoCA, was administered and a score of
less than 26 was considered abnormal.  Results In this study, the
participants on metformin had a statistically significant correlation with
age > 65 years, duration of diabetes (>5 years), metformin
dose (1 gm and more) and presence of diabetes complications. Ordinal
regressions showed significant correlation between abnormal MoCA scores
and older age, longer duration of DM, and presence of one of the DM
complications. Conclusions Amongst patients receiving medical therapy for
control of type 2 diabetes, participants using metformin showed a very
high prevalence rate of abnormal MoCA scores (85%). Increased duration of
metformin intake leads to a decline in MoCA performance.