A longitudinal study, using HbA1c data from the National Health Laboratory Service for CCMDD-enrolled patients in eThekwini, South Africa from 2018–2021, was performed. We included patients optimally controlled at their baseline HbA1c, and having ≥1 repeat test available. We used Kaplan Meier analysis to assess survival rates and Cox regression to determine associations between time to sub-optimal control (HbA1c &amp;gt;7%) and several factors. Adjusted hazard rates (aHR), 95% confidence interval and p-values are reported.