Materials and methods

Study design and setting

This retrospective cross-sectional study was conducted through a secondary analysis of a clinical database from CAD Diabetes Care Center, a specialized metabolic and cardiovascular center in Tampico, Tamaulipas, Mexico. Data were collected from clinical records dated between May 20, 2024, and April 30, 2026. The database included patients with T2DM who received outpatient care at the center. The study was designed to evaluate the association between type of antidiabetic treatment and glycemic control in routine clinical practice.

Study population

A total of 1,509 clinical records with patient identifiers were initially assessed for eligibility. Patients were included if they had a documented diagnosis of T2DM, available HbA1c data, available clinical and anthropometric information, and a clearly documented type of antidiabetic treatment. Only patients treated with oral antidiabetic therapy alone or combined insulin plus oral antidiabetic therapy were included. Records were excluded if they had missing or incomplete data for the main outcome variable, unclear treatment classification, a diagnosis other than T2DM, duplicate or nonvalid entries, or treatment regimens outside the two study groups. After applying the inclusion and exclusion criteria, 995 patients were included in the final analysis.

Variables and definitions

The primary outcome was glycemic control, which was determined using HbA1c as the main outcome indicator. Patients with HbA1c ≤7% were classified as having adequate glycemic control, whereas those with HbA1c >7% were classified as uncontrolled. The main independent variable was type of antidiabetic treatment. The oral therapy group included patients treated with oral antidiabetic agents only, while the combined therapy group included patients treated with insulin plus oral antidiabetic agents.

Additional covariates included age, sex, duration of T2DM, systolic blood pressure, diastolic blood pressure, height, weight, BMI, and BMI category. BMI was calculated as weight in kilograms divided by height in meters squared. For analysis, BMI was categorized using three predefined adult BMI groups, namely, BMI <25 kg/m², 25-29.9 kg/m², and ≥30 kg/m², corresponding to normal or underweight, overweight, and obesity, respectively.

Statistical analysis

Data were analyzed using IBM SPSS Statistics for Windows, Version 27.0 (IBM Corp., Armonk, New York, United States). Continuous variables were assessed for normality using the Shapiro-Wilk test and visual inspection of histograms and Q-Q plots. Homogeneity of variances between groups was assessed using Levene's test. Continuous variables were summarized as means and standard deviations, while categorical variables were presented as frequencies and percentages. Because of the large sample size, continuous variables were compared between treatment groups using Student's t-test, with consideration of variance homogeneity. Categorical variables were compared using Pearson's chi-squared test.

The association between type of antidiabetic treatment and glycemic control was first evaluated using Pearson's chi-squared test. Cramer's V was calculated to estimate the strength of the association. A multivariable logistic regression model was then performed to evaluate the independent association between type of antidiabetic treatment and glycemic control. The dependent variable was glycemic control, coded as 0 for uncontrolled and 1 for controlled. Independent variables included in the model were type of antidiabetic treatment, age, sex, duration of T2DM, and BMI. Results were reported as odds ratios with 95% confidence intervals. A p-value of <0.05 was considered statistically significant.