Starting therapy with an SGLT2 inhibitor versus a glucagon-like peptide-1 (GLP-1) receptor agonist was associated with more lower limb amputations, nonvertebral fractures, and genital infections, but these risks need to be balanced against cardiovascular and renoprotective benefits, according to the researchers.
The analysis showed that there would be 2.1 more lower limb amputations, 2.5 more nonvertebral fractures, and 41 more genital infections per 1,000 patients per year among those receiving SGLT2 inhibitors versus an equal number of patients receiving GLP-1 agonists, lead author Edouard Fu, PhD, explained to this news organization in an email.
“On the other hand, we know from the evidence from randomized controlled trials that taking an SGLT2 inhibitor compared with placebo lowers the risk of developing kidney failure,” said Dr. Fu, who is a research fellow in the division of pharmacoepidemiology and pharmacoeconomics at Brigham and Women’s Hospital, Boston.
“For instance,” he continued, “in the DAPA-CKD clinical trial, dapagliflozin versus placebo led to 29 fewer events per 1,000 patients per year of the composite outcome (50% decline in estimated glomerular filtration rate [eGFR], kidney failure, cardiovascular or kidney death).”
In the CREDENCE trial, canagliflozin versus placebo led to 18 fewer events per 1,000 person-years for the composite outcome of doubling of serum creatinine, kidney failure, and cardiovascular or kidney death.
And in the EMPA-KIDNEY study, empagliflozin versus placebo led to 21 fewer events per 1,000 person-years for the composite outcome of progression of kidney disease or cardiovascular death.
“Thus, benefits would still outweigh the risks,” Dr. Fu emphasized.
‘Quantifies absolute rate of events among routine care patients’
“The importance of our paper,” he summarized, “is that it quantifies the absolute rate of events among routine care patients and may be used to inform shared decision-making.”
The analysis also found that the risks of diabetic ketoacidosis (DKA), hypovolemia, hypoglycemia, and severe urinary tract infection (UTI) were similar with SGLT2 inhibitors versus GLP-1 agonists, but the risk of developing acute kidney injury (AKI) was lower with an SGLT2 inhibitor.
“Our study can help inform patient-physician decision-making regarding risks and benefits before prescribing SGLT2 inhibitors in this population” of patients with CKD and diabetes treated in clinical practice, the researchers conclude, “but needs to be interpreted in light of its limitations, including residual confounding, short follow-up time, and the use of diagnosis codes to identify patients with CKD.”
The study was recently published in the Clinical Journal of the American Society of Nephrology.
Slow uptake, safety concerns
SGLT2 inhibitors are recommended as first-line therapy in patients with type 2 diabetes and CKD who have an eGFR equal to or greater than 20 mL/min per 1.73 m2, and thus are at high risk for cardiovascular disease and kidney disease progression, Dr. Fu and colleagues write.
However, studies report that as few as 6% of patients with CKD and type 2 diabetes are currently prescribed SGLT2 inhibitors in the United States.
This slow uptake of SGLT2 inhibitors among patients with CKD may be partly due to concerns about DKA, fractures, amputations, and urogenital infections observed in clinical trials.
However, such trials are generally underpowered to assess rare adverse events, use monitoring protocols to lower the risk of adverse events, and include a highly selected patient population, and so safety in routine clinical practice is often unclear.
To examine this, the researchers identified health insurance claims data from 96,128 individuals (from Optum, IBM MarketScan, and Medicare databases) who were 18 years or older (65 years or older for Medicare) and had type 2 diabetes and at least one inpatient or two outpatient diagnostic codes for stage 3 or 4 CKD.
Of these patients, 32,192 had a newly filled prescription for an SGLT2 inhibitor (empagliflozin, dapagliflozin, canagliflozin, or ertugliflozin) and 63,936 had a newly filled prescription for a GLP-1 agonist (liraglutide, dulaglutide, semaglutide, exenatide, albiglutide, or lixisenatide) between April 2013, when the first SGLT2 inhibitor was available in the United States, and 2021.
The researchers matched 28,847 individuals who were initiated on an SGLT2 inhibitor with an equal number who were initiated on a GLP-1 agonist, based on propensity scores, adjusting for more than 120 baseline characteristics.
Safety outcomes were based on previously identified potential safety signals.
Patients who were initiated on an SGLT2 inhibitor had 1.30-fold, 2.13-fold, and 3.08-fold higher risks of having a nonvertebral fracture, a lower limb amputation, and a genital infection, respectively, compared with patients who were initiated on a GLP-1 agonist, after a mean on-treatment time of 7.5 months,
Risks of DKA, hypovolemia, hypoglycemia, and severe UTI were similar in both groups.
Patients initiated on an SGLT2 inhibitor versus a GLP-1 agonist had a lower risk of AKI (hazard ratio, 0.93) equivalent to 6.75 fewer cases of AKI per 1,000 patients per year.
Patients had higher risks for lower limb amputation, genital infections, and nonvertebral fractures with SGLT2 inhibitors versus GLP-1 agonists across most of the prespecified subgroups by age, sex, cardiovascular disease, heart failure, and use of metformin, insulin, or sulfonylurea, but with wider confidence intervals.
Dr. Fu was supported by a Rubicon grant from the Dutch Research Council and has reported no relevant financial relationships. Disclosures for the other authors are listed with the article.
A version of this article originally appeared on Medscape.com.