Background. The purpose of this study was to investigate how the degree of glycemic control in patients with type 2 diabetes associated with lifestyle interventions as well as sociodemographic factors and further examine the differences by gender. Methods. This was a retrospective study using data collected from a diabetes quality improvement plan that began in 2002 in a medical center in Taiwan. Statistic analysis was used to determine the associations of sociodemographic data, lifestyle intervention, and treatment regimens with changes in HbA1c levels (between the initial visit and the latest follow-up measured level), and the differences were then sorted by the sex of the patients. Results. Our results showed that HbA1c averaged 7.50% for males and 7.80% for females at the initial visit, compared to levels averaging 7.50% for males and 7.70% for females at the most recent follow-up visit. There was no significant change (P = 0.541) in HbA1c in males, but there was a 0.10% (P = 0.384) reduction in females. The duration of the diabetes and medication regimen was associated with the decrease seen in the females. Conclusions. The results of these analyses provide important insights for policy makers to formulate healthcare policies related to chronic diseases or illnesses.