Adjunct Synbiotic Therapy with Vildagliptin–Metformin Improves Glycemic Control, Insulin Sensitivity, and Cost-Efficiency in Elderly Patients with Type 2 Diabetes
Adjunct Synbiotic Therapy with Vildagliptin–Metformin
Keywords:
Type 2 diabetes, vildagliptin, synbiotics,, metforminAbstract
Background: Elderly patients with type 2 diabetes mellitus (T2DM) face therapeutic challenges due to multimorbidity, polypharmacy, and suboptimal glycemic control despite standard oral therapy. Gut microbiota modulation through synbiotics has emerged as a potential strategy to enhance insulin sensitivity and improve metabolic outcomes.
Objective: To evaluate the efficacy, safety, adherence, and economic feasibility of adding a synbiotic supplement to vildagliptin–metformin therapy in elderly Indian patients with T2DM.
Methods: In this randomized, open-label, controlled trial, 356 patients were screened, and 320 were randomized. A total of 210 participants (mean age 71.2 ± 6.1 years; 105 per arm) completed the 12-week study. Group 1 received vildagliptin 50 mg plus metformin 500 mg twice daily, while Group 2 received the same regimen with a daily synbiotic capsule (Lactobacillus and Bifidobacterium ≥10^9 CFU each, with 100 mg fructo-oligosaccharides). Primary outcomes were changes in fasting blood glucose (FBS), postprandial blood glucose (PPBS), HbA1c, and triglyceride–glucose (TyG) index. Secondary outcomes included safety, adherence, polypharmacy tolerability, and incremental cost-effectiveness.
Results: Both groups showed significant glycemic improvements; however, the synbiotic arm demonstrated greater reductions in FBS (−29.9 vs −15.2 mg/dL), PPBS (−39.8 vs −21.2 mg/dL), and HbA1c (−1.2% vs −0.6%, p<0.001). The TyG index improved more in Group 2 (−0.47 vs −0.21, p<0.001). Benefits were consistent across sex and age strata, with slightly greater effects in patients ≥70 years. Adverse events were mild gastrointestinal complaints, more frequent in the synbiotic group (25% vs 19%), but no severe events occurred. High adherence (≥90%) was maintained in >80% of participants in both groups, even among those with polypharmacy. Economic analysis showed that although synbiotic therapy increased monthly costs by ~₹300, the cost per 1% HbA1c reduction was lower in Group 2 (₹625 vs ₹750), with an incremental cost-effectiveness ratio of ~₹500 per additional 0.5% HbA1c reduction.
Conclusion: The addition of synbiotics to vildagliptin–metformin therapy in elderly T2DM patients significantly improved glycemic control, insulin sensitivity, and overall cost-efficiency without compromising safety or adherence. This gut-targeted adjunct represents a clinically effective and economically rational strategy for diabetes management in the Indian context.
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