Discussion

The main finding of this study was that type of antidiabetic treatment was significantly associated with glycemic control in patients with T2DM. Patients receiving oral antidiabetic therapy had a higher proportion of adequate glycemic control compared with those receiving combined insulin plus oral antidiabetic therapy. This association remained statistically significant after adjustment for age, sex, duration of T2DM, and BMI. However, these findings should not be interpreted as evidence that oral antidiabetic therapy is superior to combined insulin plus oral antidiabetic therapy. Rather, they likely reflect important clinical differences between treatment groups, particularly longer diabetes duration and more advanced disease among patients requiring insulin.

Patients receiving combined insulin plus oral antidiabetic therapy had a substantially longer duration of T2DM than those treated with oral antidiabetic therapy alone. This finding is clinically relevant because T2DM is a progressive disease in which maintaining glycemic targets becomes increasingly difficult over time. Current recommendations emphasize individualized, patient-centered treatment selection and timely intensification when glycemic goals are not achieved [5,6]. Therefore, patients requiring insulin therapy frequently represent a clinically more complex population with more advanced metabolic deterioration, higher treatment burden, and greater difficulty achieving glycemic control.

In the present study, the lower proportion of glycemic control observed among patients receiving combined insulin plus oral antidiabetic therapy should be interpreted in relation to the clinical characteristics identified in the analysis. This group had a longer duration of T2DM and higher HbA1c levels at baseline, suggesting a more advanced stage of disease and greater difficulty achieving glycemic targets. In the multivariable model, duration of T2DM remained independently associated with lower odds of glycemic control, supporting its relevance as one of the main indicators related to inadequate metabolic control in this sample. These findings are consistent with recent evidence showing that longer diabetes duration and greater treatment complexity are associated with poorer glycemic outcomes in patients with T2DM [13-17].

The association between longer duration of T2DM and poorer glycemic control was also observed in the adjusted regression model. Each additional year of diabetes duration was associated with lower odds of adequate glycemic control. This finding is consistent with recent evidence identifying longer diabetes duration as an important factor associated with poor glycemic control [15-17]. These findings reinforce the importance of early optimization of glucose-lowering therapy before patients progress to more advanced stages requiring insulin.

Age was positively associated with glycemic control in the adjusted model. Although this association was statistically significant, it should be interpreted cautiously. Older patients may have closer medical follow-up, greater adherence to treatment, or more frequent clinical monitoring. However, this study did not evaluate adherence, frequency of visits, socioeconomic factors, comorbidities, or treatment intensity. Therefore, the association between age and glycemic control may be influenced by unmeasured factors. Individualized glycemic targets are recommended in clinical practice, particularly when considering age, comorbidities, hypoglycemia risk, and treatment burden [5].

BMI was not independently associated with glycemic control after adjustment. Although BMI differed between treatment groups in the baseline analysis, its effect was no longer significant in the multivariable model. This suggests that, in this sample, diabetes duration and type of antidiabetic treatment were more strongly associated with glycemic control than BMI. Poor glycemic control in T2DM is multifactorial and may be influenced by treatment complexity, medication adherence, comorbidities, diabetes duration, healthcare access, and follow-up patterns [15-17].

An important clinical implication of these findings is that patients receiving combined insulin plus oral antidiabetic therapy should be recognized as a high-risk group for inadequate glycemic control. These patients may benefit from closer follow-up, structured diabetes education, assessment of adherence, optimization of insulin regimens, and identification of barriers to treatment. Clinical inertia has also been reported as a relevant barrier to treatment intensification in patients with T2DM, supporting the need for earlier recognition of patients at risk of persistent inadequate glycemic control [18]. In real-world clinical practice, identifying patients with longer diabetes duration, higher HbA1c levels, and greater treatment complexity may help guide closer follow-up and individualized therapeutic optimization.

This study has several limitations. First, its retrospective cross-sectional design prevents establishing causal relationships between type of antidiabetic treatment and glycemic control. Second, the study was conducted at a single specialized metabolic and cardiovascular center, which may limit the generalizability of the findings to other clinical settings. Third, the analysis did not include potentially relevant variables such as medication adherence, insulin dose, type of insulin regimen, specific oral antidiabetic agents, renal function, comorbidities, socioeconomic status, diet, physical activity, or frequency of follow-up. Fourth, glycemic control was assessed using HbA1c at a single point in time, and longitudinal changes in glycemic control could not be evaluated. Finally, residual confounding is possible despite multivariable adjustment.

Despite these limitations, this study provides real-world evidence on the association between type of antidiabetic treatment and glycemic control in a large sample of patients with T2DM. The findings emphasize that patients receiving combined insulin plus oral antidiabetic therapy often represent a clinically more complex group with longer disease duration and a lower probability of meeting glycemic targets. Therefore, treatment comparisons in observational studies should be interpreted in the context of disease severity, treatment complexity, and baseline clinical differences.