Triple oral therapy with metformin, SGLT-2, and DPP-4 inhibitors lowers HbA1c better than dual regimens in adults with type 2 diabetes

This systematic review and meta-analysis evaluated the efficacy and safety of triple oral therapy versus dual therapy in adults with type 2 diabetes mellitus. The study pooled data from multiple trials involving 2,606 participants to assess the impact of combining metformin with both an SGLT-2 inhibitor and a DPP-4 inhibitor. The primary outcome focused on hemoglobin A1c (HbA1c) reduction, while secondary outcomes included fasting plasma glucose, body weight, achievement of HbA1c below 7%, and adverse events.

The analysis revealed that triple therapy significantly reduced HbA1c levels compared to dual therapy, with a standardized mean difference of -0.54. The 95% confidence interval ranged from -0.92 to -0.16, and the p-value was 0.005, indicating statistical significance. This suggests a clinically meaningful improvement in glycemic control when adding a third agent to the regimen. Patients on triple therapy were also more likely to achieve HbA1c levels below 7%, with a relative risk of 2.02 and a p-value less than 0.0001.

Regarding fasting plasma glucose, triple therapy resulted in a greater reduction than dual therapy, though the difference did not reach statistical significance (p = 0.06). The standardized mean difference was -0.30, with a 95% confidence interval of -0.62 to 0.01. This trend supports the additive effect of the third agent, even if the specific glucose metric showed borderline significance in this pooled analysis.

Body weight changes were observed with triple therapy, showing a modest reduction compared to dual therapy. The standardized mean difference was -0.14, with a 95% confidence interval of -0.22 to -0.07 and a p-value of 0.0002. While the weight loss was statistically significant, the magnitude was described as modest, which is consistent with the mechanisms of these oral agents.

Safety analysis indicated no significant differences in total adverse events between the two groups. The relative risk was 0.97 with a p-value of 0.69, suggesting that adding the third agent did not increase the overall risk of side effects. However, discontinuations due to adverse events were higher in the triple therapy group, with a relative risk of 2.62 and a p-value of 0.03. This highlights a potential trade-off between efficacy and tolerability, as some patients may discontinue treatment due to specific side effects.

The study limitations were not explicitly detailed in the provided data, but the absence of data on serious adverse events and tolerability metrics suggests areas for further investigation. The findings support the use of triple oral therapy as an effective strategy for achieving glycemic targets in adults with type 2 diabetes, particularly for those who have not reached goals with dual therapy. Clinicians should weigh the benefits of improved HbA1c control against the increased risk of discontinuation due to adverse events when considering this approach.