Introduction: Insulin deintensification is an emerging strategy to reduce hypoglycemia and treatment burden in patients on multiple daily injection (MDI ≥3), with potential to improve adherence and glycemic control. However, evidence in poorly controlled type 2 diabetes mellitus (T2DM) remains limited. This study evaluated its effectiveness and identified factors associated with achieving adequate glycemic control following deintensification among patients with poorly controlled T2DM attending Malaysian primary care. Methodology: A retrospective cohort study was conducted among 107 T2DM patients with hemoglobin A1c (HbA1c) >9%, attending Enhanced Diabetic Clinic at Cheras Health Clinic between 2021 and 2025. All patients on basal-bolus insulin (BBI) underwent deintensification. Multivariate logistic regression was performed to identify factors associated with achieving adequate glycemic control (HbA1c <7.5%). Changes in HbA1c following deintensification were assessed using paired t-tests. Results: Overall, 50.5% of patients achieved adequate glycemic control. Hypoglycemia events (AOR 9.5, 95% confidence interval [CI] 1.6–58.3; p = 0.015), MDI (AOR 9.6, 95% CI 1.4–67.1; p = 0.023) and Diabetes Medication Therapy Adherence Clinic (DMTAC) visits (AOR 1.1, 95% CI 1.0– 1.2; p = 0.039) were significantly associated with achieving HbA1c <7.5%. Conversely, patients transitioned from BBI to premixed regimens were less likely to achieve HbA1c <7.5% (AOR 0.22, 95% CI 0.05–0.93, p = 0.039). All insulin deintensification strategies were associated with significant HbA1c improvements with transitioned from BBI to premixed human insulin (mean difference -2.54%, 95% CI 1.77–3.31, p <0.001, Cohen’s d = 1.09), BBI to premixed analogue insulin (mean difference -3.38%, 95% CI 2.26– 4.49, p <0.001, Cohen’s d = 1.62), BBI to basal insulin (mean difference -3.67%, 95% CI 1.79–5.54, p = 0.004, Cohen’s d = 2.05). Conclusion Insulin deintensification is an effective strategy for improving glycemic control in poorly controlled T2DM. These findings highlight the importance of deintensification with careful consideration of hypoglycemia, MDI-related treatment burden, and patient engagement through regular DMTAC visits, which are integral to achieving optimal outcomes and support a personalized approach to diabetes management in primary care.
Diabetes Mellitus, Type 2 ; Glycemic Control ; Retrospective Studies ; Primary Health Care ; Insulins