Fig. 3: Metformin reduces incident dementia relative to sulfonylureas in type 2-diabetic patients aged >50 years at treatment initiation.

HRs were estimated using the Cox PH model for the cause-specific hazards of dementia, with only treatment as a covariate and baseline covariate distributions between treatment arms balanced by IPTW. a, b Forest plots present HRs overall and stratified by age, sex, and BMI level at baseline, with sulfonylureas as the reference group. N = # of patients at baseline, Onsets = # of patients with dementia onset during follow-up and prior to death. Covariate balancing using IPTW was conducted in each stratum independently. Error bars represent 95% CIs for hazard ratios. A two-sided Wald test of whether the hazard ratio associated with metformin treatment initiation is 1, with robust variance estimator, was used. No further correction for multiple hypothesis testing was applied.