Miller RG, et al. - In patients with type 1 diabetes (T1D), HbA1c (%)-measured hyperglycemia has been an inconsistent cardiovascular disease (CVD) predictor; however, only baseline HbA1c or a summary measure (e.g., mean over follow-up) is usually analyzed. Joint models allow longitudinal repeated covariates, modeled using random effects, and time-to-event data to be modeled simultaneously. Herein, data from the Pittsburgh Epidemiology of Diabetes Complications (EDC) study were analyzed. The results supported the requirement for good glycemic control to prevent CVD in T1D. Also, the data highlighted the importance of using methods incorporating within-subject variation over time when analyzing and interpreting longitudinal cohort study data.