Methodology of clinical trials on sodium-glucose cotransporter 2 inhibitors registered on ClinicalTrials.gov: a cross-sectional study

Abstract

Background/Objective The research on sodium-glucose cotransporter 2 (SGLT2) inhibitors has been increasing rapidly in the last decade, as well as indications for their use. This study aimed to analyze the methodological characteristics of clinical trials on SGLT2 inhibitors registered on ClinicalTrials.gov. Design We conducted a cross-sectional study of trials on SGLT2 inhibitors registered on ClinicalTrials.gov up to November 11, 2022. We included clinical trials that tested SGLT2 inhibitors for any clinical condition, as a single or combined SGLT2 therapy, compared to any other medication or placebo and mapped their characteristics. Results We identified 1102 eligible trials on 14 different SGLT2 inhibitors. The first trial registration was in 2005. There were 993 (90%) interventional and 109 (10%) observational trials. Most trials were in Phase 1 (29%), Phase 3 (23%), or Phase 4 (24%). Interventional trials were mostly randomized (85%); almost half of them did not use masking (44%). Trials on empagliflozin, dapagliflozin, and canagliflozin accounted for 75% of all trials. More than 60% of trials included patients with diabetes mellitus, 13% included only healthy subjects, and 12% included patients with heart diseases. Overall, these trials included more than 9.5 million participants (~ 312,000 of which in interventional studies). Almost 65% of all clinical trials were industry-funded. Most trials were completed (60%) and 35% of those reported results. For trials that are obligated to report results by the Food and Drugs Administration (FDA), 88% of them did so. Trials fully or partially funded by industry more frequently published results compared to non-industry funded trials (46.1% vs. 11.2%; p < 0.001). Conclusions The number of registered trials on SGLT2 inhibitors is increasing progressively along with expanding indications for its use, shifting from diabetes mellitus to cardiovascular and renal diseases. Public reporting of trial results improved with time but remains suboptimal.