Optimal dose of tirzepatide for type 2 diabetes mellitus: A meta-analysis and trial sequential analysis

OBJECTIVE: The purpose of this study is to evaluate the optimal dose of tirzepatide (TZP) for the treatment of type 2 diabetes mellitus (T2DM) by meta-analysis and trial sequential analysis (TSA). METHODS: Clinical trials of TZP for T2DM were obtained by searching 8 databases with a time limit from database creation to May 2022. Mean differences (MD) and 95% confidence intervals (95%CI) were used for continuous variables, and relative risk (RR) and 95%CI were used for dichotomous variables. RESULTS: Compared with TZP 5 mg, meta-analysis showed that TZP 10 mg significantly reduced glycosylated hemoglobin type A1c (HbA1c) (MD −0.24, 95%CI −0.31~-0.17, P < 0.00001), fasting serum glucose (FSG) (MD −5.82, 95%CI −8.35~-3.28, P < 0.00001) and weight (MD −2.47, 95%CI −2.95~-1.98, P < 0.00001), and TZP 15 mg significantly reduced HbA1c (MD −0.37, 95%CI −0.44~-0.29, P < 0.00001), FSG (MD −8.52, 95%CI −11.07~-5.98, P < 0.00001) and weight (MD −4.63, 95%CI −5.45~-3.81, P < 0.00001). Compared with TZP 10 mg, TZP 15 mg dramatically reduced HbA1c (MD −0.12, 95%CI −0.19~-0.05, P = 0.001), FSG (MD −2.73, 95%CI −5.29~-0.17, P = 0.04) and weight (MD −2.18, 95%CI −2.67~-1.70, P < 0.00001). The TSA indicated that the benefits observed in the current information set were conclusive, except for the FSG of “TZP 15 mg vs. TZP 10 mg”. In terms of safety endpoints, meta-analysis revealed that there was no significant difference in the serious adverse events (AEs), major adverse cardiovascular events-4 (MACE-4), cardiovascular death, hypertension, cancer and hypoglycemic of the three dose groups of TZP. Compared with TZP 5 mg, TZP 10 mg increased total adverse events (RR 1.06, 95%CI 1.01~1.11, P = 0.03) and gastrointestinal (GI) AEs (RR 1.17, 95%CI 1.03~1.33, P = 0.02), and TZP 15 mg increased total AEs (RR 1.10, 95%CI 1.05~1.15, P = 0.0001). There were no significant differences in total AEs and GI AEs for TZP 15 mg compared to TZP 10 mg. The TSA demonstrated that the total AEs of “TZP 15 mg vs. TZP 5 mg” were conclusive. CONCLUSIONS: TZP 15 mg >TZP 10 mg > TZP 5 mg in terms of lowering glycemia and reducing weight. TZP 5 mg > TZP 10 mg = TZP 15 mg in terms of safety. On this basis, we recommend TZP 5 mg as the first-choice dose for patients with T2DM to minimize AEs while reducing glycemia and weight. If patients cannot effectively control their glycemia after taking TZP 5 mg, it is recommended to take TZP 15 mg directly to achieve the best effect of glycemic reduction. However, most of the included studies have the background of basic medication, the independent efficacy and safety of different doses of TZP still need to be tested. SYSTEMATIC REVIEW REGISTRATION: Unique Identifier: CRD42022341966.