The Effects of SGLT2 Inhibitors on Cardiovascular and Renal Outcomes in Diabetic Patients: A Systematic Review and Meta-Analysis

Background: Previous meta-analyses demonstrated the benefits of sodium-glucose cotransporter 2 inhibitors (SGLT2i) primarily on patients with established atherosclerotic cardiovascular disease (ASCVD), but with questionable efficacy on patients at risk of ASCVD. Additionally, evidence of beneficial cardiorenal outcomes in patients with estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m(2) with the CV outcomes trials remains unclear. Canagliflozin, one of the SGLT2i, has recently been studied in a large randomized controlled trial in diabetic patients with chronic kidney disease. Thus, there is a need to understand the combined outcomes on the population targeted for treatment with SGLT2i as a whole, regardless of ASCVD status. This meta-analysis will therefore assess the efficacy of SGLT2i in cardiovascular and renal outcomes in general, and in patients with eGFR under 60 mL/min/1.73 m(2) in particular. Methods: We searched PubMed and Cochrane databases for randomized, placebo-controlled studies involving SGLT2i. We examined composite cardiovascular outcomes of death from cardiovascular causes, nonfatal myocardial infarctions, nonfatal stroke, and heart failure hospitalizations. Renal composite outcomes and progression of albuminuria were also analyzed. Pooled relative risks (RR) and their 95% confidence intervals (CI) were calculated using a fixed-effects model. Results: The search yielded a total of 252 articles. Four studies were ultimately included in the meta-analysis after exclusion of other irrelevant studies. The pooled RR (95% CI) for the composite cardiovascular outcome was 0.93 (0.87-0.99) with a number needed to treat (NNT) of 167 in the general study population and 0.89 (0.77-1.02) in patients with eGFR <60 mL/min/1.73 m(2). The pooled RR for all-cause mortality was 0.9 (0.84-0.97) with NNT = 143. The pooled RR for death from cardiovascular causes alone was 0.89 (0.81-0.99) in the general population and 0.82 (0.62-1.07) in patients with eGFR <60 mL/min/1.73 m(2). The pooled RR for heart failure hospitalizations was 0.71 (0.63-0.79) with NNT = 91. With respect to renal outcomes, the pooled RR for the composite renal outcome was 0.63 (0.56-0.71) with NNT = 67; this was true even in patients with eGFR <60 mL/min/1.73 m(2) 0.67 (0.59-0.76). Lastly, the pooled RR for progression of albuminuria was 0.80 (0.76-0.84). Conclusion: SGLT2i are associated with significantly lower major adverse cardiovascular events, heart failure hospitalizations, and all-cause mortality. The evidence is strongest in reducing heart failure hospitalizations. However, the evidence is weaker when it comes to the population subset with eGFR <60 mL/min/1.73 m(2). SGLT2i are also associated with significantly lower adverse renal events, with these effects apparent even in the population with eGFR <60 mL/min/1.73 m(2).