Results From Cox Proportional Hazards Models Estimating the Association Between Receipt of a New Metformin vs a New Sulfonylurea Prescription Fill and Incident Dementia for FY 2002 to 2015, Stratified by Race, Among African American and White VHA Patients Aged ≥50 Years (N = 73,761)
| Model 1 Crudea | Model 2 Weightedb | Model 3 Weighted + AMGBc | Model 4 Weighted + Hypoglycemiad | |
|---|---|---|---|---|
| Race | MET vs SU, HR (95% CI) | MET vs SU, HR (95% CI) | MET vs SU, HR (95% CI) | MET vs SU, HR (95% CI) |
| Whitee | 0.67 (0.63-0.71) | 0.96 (0.9-1.03) | 0.92 (0.86-0.99) | 0.98 (0.92-1.05) |
| African Americane | 0.6 (0.51-0.71) | 0.73 (0.6-0.89) | 0.72 (0.58-0.88) | 0.77 (0.64-0.94) |
| Race * drug, P valuef | .207 | .008 | .026 | .022 |
AMGB = average monthly glycemic burden; FY = fiscal year; HbA1c = hemoglobin A1c; HR = hazard ratio; MET = metformin; SU = sulfonylurea; VHA = Veterans Health Administration.
↵a Unweighted data.
↵b Inverse probability of treatment weighted data with robust, sandwich-type variance estimators.
↵c Additional adjustment for glycemic burden from MET/SU initiation to end of follow-up among a subset of 69,918 African American and white VHA patients with at least 2 HbA1c values after MET/SU initiation.
↵d Additional adjustment for time-dependent hypoglycemia episode after MET/SU initiation.
↵e Proportional hazard assumption P value: white = .244; African American = .07.
↵f Interaction P value testing differential effect of race on MET vs SU for each model.