Effect of combination pioglitazone with sodium-glucose cotransporter-2 inhibitors or glucagon-like peptide-1 receptor agonists on outcomes in type 2 diabetes: A systematic review, meta-analysis, and real-world study from an international federated database

Aims: To evaluate the efficacy and cardiovascular outcomes of combination pioglitazone with either a glucagon-like peptide-1 receptor agonist (GLP-1RA) or a sodium-glucose cotransporter-2 (SGLT2) inhibitor in individuals with type 2 diabetes (T2D) by conducting a systematic review, meta-analysis, and analysis of a large international real-world database. Methods: We searched MEDLINE, SCOPUS and Web of Science to identify relevant articles for inclusion (PROSPERO [CRD: 42023483126]). Nineteen studies assessing pioglitazone + SGLT2 inhibitors or GLP-1RAs versus controls were identified, 16 of which were randomized controlled trials. Risk of bias was assessed using Cochrane-endorsed tools and quality of evidence was assessed using GRADE. We additionally performed a retrospective cohort study of all individuals aged 18 years or over with T2D, using the TriNetX platform. We included propensity-score-matched individuals who were treated for at least 1 year with pioglitazone and a GLP-1RA or pioglitazone and an SGLT2 inhibitor, compared against GLP-1RA and SGLT2 inhibitor monotherapy. Outcomes were all-cause mortality, heart failure, chronic kidney disease and composite stroke and transient ischaemic attack. Results: The average follow-up in the included studies ranged from 24 to 52 weeks. Combination of pioglitazone with a GLP-1RA reduced glycated haemoglobin (HbA1c) and weight greater than in controls: mean differences -1% (95% confidence interval [CI] -1.27, -0.74) and -1.19 kg (95% CI -1.80, -0.58), respectively. There was no statistically significant difference in systolic blood pressure (SBP) or mortality between groups: mean difference - 1.56 mmHg (95% CI -4.48, 1.35; p = 0.30) and relative risk (RR) 0.29 (95% CI 0.07-1.15; p = 0.08), respectively. Combination of pioglitazone with SGLT2 inhibitors reduced HbA1c, weight and SBP to a greater extent than control treatment: mean differences -0.48% (95% CI -0.67, -0.28), -2.3 kg (95% CI -2.72, -1.88) and -2.4 mmHg (95% CI -4.1, -0.7; p = 0.01), respectively. There was no statistically significant difference in mortality between groups (RR 1.81, 95% CI 0.30-10.97; p = 0.52). The included trials demonstrated a reduction in risk of heart failure with combination treatment. Similarly, from the real-world database (n = 25 230 identified), pioglitazone and SGLT2 inhibitor combination therapy was associated with reduced risk of heart failure compared to monotherapy alone (hazard ratio 0.50, 95% CI 0.38-0.65; p < 0.001). Conclusion: Both our systematic review/meta-analysis and the real-world dataset show that combination of pioglitazone with either GLP-1RAs or SGLT2 inhibitors is associated with increased weight loss and reduced risk of heart failure compared with monotherapy.