Mechanisms of SGLT inhibitor action and physiological mediators:systematic review and protocol for the MOSAIC collaborative meta-analysis

INTRODUCTION: Sodium-glucose cotransporter (SGLT) inhibitors have shown substantial benefit in reducing cardiovascular and kidney events across diverse clinical populations, but the underlying physiological mechanisms remain unclear. However, existing mechanistic studies on renal and cardiovascular haemodynamics show variability in design, have limited statistical power and yield inconsistent outcomes, thus limiting the ability to draw generalisable conclusions. To address this gap, we conducted a systematic review and proposed the first meta-analysis to aggregate individual participant-level data from mechanistic studies to identify consistent physiological patterns and enhance understanding of the therapeutic effects of SGLT inhibition. METHODS AND ANALYSIS: Gold-standard measured glomerular filtration rate (mGFR) was selected as the primary outcome for this systematic review, which aimed to identify all completed mechanistic studies investigating the effects of SGLT inhibition. Electronic databases including Ovid MEDLINE; Ovid Embase; Cochrane Database of Systematic Reviews; and Cochrane Central Register of Controlled Trials were searched using a detailed search strategy. In total, 24 studies (n=1296) were identified. This systematic review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Key variables including demographics, medical history, concomitant medications, vital signs, mGFR, renal haemodynamics, urine and plasma biochemistry, tubular sodium handling, echocardiography, cardiac output monitoring, arterial stiffness and fluid volume will be extracted. A one-stage individual participant data meta-analysis under a Bayesian framework will be conducted, using hierarchical models to simultaneously analyse data from all eligible studies. The risk of bias due to missing results will be assessed. Sensitivity analyses and subgroup evaluations will be incorporated to explore sources of heterogeneity and assess robustness of findings. ETHICS ...