The final cohort included 87,600 patients with type 2 diabetes who were initiators of therapy with metformin (n = 71,472) or an SU (n = 16,128). Approximately 8% of initiators (n = 7,352) left a THIN practice during follow-up. The median follow-up time was ∼2 years for both cohorts (metformin cohort: median 2.1 years [interquartile range {IQR} 0.8–4.0 years] vs. SU cohort: median 2.0 years [IQR 0.7–3.9 years]), and >4 years in 25% of subjects