When it comes to managing type 2 diabetes, the choice of medication can have significant implications for overall health, particularly regarding kidney function. New research reveals a striking correlation: starting sodium-glucose cotransporter-2 inhibitors (SGLT2is) is associated with a reduced risk of chronic kidney disease (CKD) and fewer instances of acute kidney injury (AKI) compared to glucagon-like peptide-1 receptor agonists (GLP-1 RAs). This comparison is crucial in a landscape where both classes of drugs are commonly prescribed, yet their effects on kidney health have not been definitively clarified until now.
Published in JAMA Internal Medicine, this study sheds light on the comparative effectiveness of these two medication types. The researchers noted, “To our knowledge, no head-to-head randomized clinical trials have directly compared the effectiveness of SGLT2is vs. GLP-1RAs in reducing CKD and AKI.” Previous meta-analyses had yielded inconsistent results, leaving healthcare providers and patients in a state of uncertainty regarding the best therapeutic approach for safeguarding kidney health.
SGLT2 inhibitors are oral medications that function by obstructing the action of the sodium-glucose cotransporter-2 protein in the kidneys. This mechanism helps lower blood glucose levels by preventing the reabsorption of glucose back into the bloodstream, promoting its excretion through urine. In addition to their role in diabetes management, SGLT2is are also beneficial for individuals with heart failure and CKD, as they can significantly reduce hospitalizations and slow the progression of kidney disease.
To arrive at their conclusions, the researchers analyzed extensive population-based registry data from Denmark, examining outcomes for individuals with type 2 diabetes treated with metformin who initiated either SGLT2is or GLP-1 RAs between January 2014 and November 2020, monitoring them through to October 2024. This robust analysis included 55,061 participants, where 36,279 began treatment with SGLT2is and 18,782 started on GLP-1 RAs. Notably, both groups exhibited similar initial diabetes duration, kidney function, and levels of albuminuria.
Over the five-year follow-up period, the results were compelling. The incidence of CKD was significantly lower among those who began SGLT2is—6.7% compared to 8.2% for GLP-1 RA initiators, translating to a risk ratio of 0.81. Furthermore, the average occurrence of AKI was also reduced in the SGLT2i group, reporting a mean count of 25.2 events per 100 individuals, versus 28.7 events for those on GLP-1 RAs, with a notable difference of -3.5 events.
Interestingly, while the primary outcomes favored SGLT2is, secondary outcomes indicated modest benefits in terms of lower albuminuria and mortality rates among GLP-1 RA users. These findings remained consistent across various subgroups, with the most significant reductions in CKD and AKI noted in individuals without prior kidney disease.
However, the researchers acknowledged several limitations in their study. The lack of random assignment raises concerns about potential confounding factors, and the absence of body mass index data could influence results, although sensitivity analyses still supported the findings. Additionally, the reliance on registry data may carry risks of misclassification, despite efforts to use validated algorithms and definitions to mitigate this concern. The applicability of the findings might also be limited, as the study focused on a Nordic population, which may not reflect the broader global demographic diversity.
Despite these reservations, the researchers concluded that beginning treatment with SGLT2 inhibitors in patients with type 2 diabetes appears to correlate with a lower five-year risk of CKD and fewer episodes of AKI compared to GLP-1 RAs. They emphasized that the pronounced differences in kidney outcomes, particularly among those without pre-existing kidney conditions, highlight a promising opportunity for primary prevention strategies. The researchers also pointed out that the divergent effects on estimated glomerular filtration rate (eGFR) and albuminuria suggest that exploring combination therapies could yield even greater benefits, warranting further investigation in future studies.
