SGLT2 Inhibitors Cut AFib Risk in Real-World Analysis

Mitchel L. Zoler, PhD

June 14, 2022

Dr Elisabetta Patorno

The case continues to grow for prioritizing a sodium-glucose transporter 2 (SGLT2) inhibitor in patients with type 2 diabetes, as real-world evidence of benefit and safety accumulates on top of the data from randomized trials that first established this class as a management pillar.

Another important effect of these agents gaining increasing currency, on top of their well-established benefits in patients with type 2 diabetes for preventing acute heart failure exacerbations and slowing progression of diabetic kidney disease, is that they cut the incidence of new-onset atrial fibrillation (AFib). That effect was confirmed in an analysis of data from about 300,000 U.S. patients included in recent Medicare records, Elisabetta Patorno, MDreported at the annual scientific sessions of the American Diabetes Association.

But despite documentation like this, real-world evidence also continues to show limited uptake of SGLT2 inhibitors in U.S. patients with type 2 diabetes. Records from more than 1.3 million patients with type 2 diabetes managed in the Veterans Affairs Healthcare System during 2019 or 2022 documented that just 10% of these patients received an agent from this class, even though all were eligible to receive it, according to findings in a separate report at the meeting.

The AFib analysis analyzed two sets of propensity score–matched Medicare patients during 2013-2018 aged 65 years or older with type 2 diabetes and no history of AFib. One analysis focused on 80,475 matched patients who started on treatment with either an SGLT2 inhibitor or a glucagonlike peptide–1 (GLP-1) receptor agonist, and a second on 74,868 matched patients who began either an SGTL2 inhibitor or a dipeptidyl peptidase–4 (DPP4) inhibitor. In both analyses, matching involved more than 130 variables. In both pair sets, patients at baseline averaged about 72 years old, nearly two-thirds were women, about 8%-9% had heart failure, 77%-80% were on metformin, and 20%-25% were using insulin.

The study's primary endpoint was the incidence of hospitalization for AFib, which occurred a significant 18% less often in the patients who started on an SGLT2, compared with those who started a DPP4 inhibitor during median follow-up of 6.7 months, and a significant 10% less often, compared with those starting a GLP-1 receptor agonist during a median follow-up of 6.0 months, Elisabetta Patorno, MD, DrPH, reported at the meeting. This worked out to 3.7 fewer hospitalizations for AFib per 1,000 patient-years of follow-up among the people who received an SGLT2 inhibitor, compared with a DPP4 inhibitor, and a decrease of 1.8 hospitalizations/1,000 patient-years when compared against patients in a GLP-1 receptor agonist.

Two secondary outcomes showed significantly fewer episodes of newly diagnosed AFib, and significantly fewer patients initiating AFib treatment among those who received an SGLT2 inhibitor relative to the comparator groups. In addition, these associations were consistent across subgroup analyses that divided patients by their age, sex, history of heart failure, and history of atherosclerotic cardiovascular disease.

AFib Effects Add to Benefits

The findings "suggest that initiation of an SGLT2 inhibitor may be beneficial in older adults with type 2 diabetes who are at risk for AFib," said Patorno, a researcher in the division of pharmacoepidemiology and pharmacoeconomics at Brigham and Women's Hospital, Boston. "These new findings on AFib may be helpful when weighing the potential risks and benefits of various glucose-lowering drugs in older patients with type 2 diabetes."

This new evidence follows several prior reports from other research groups of data supporting an AFib benefit from SGLT2 inhibitors. The earlier reports include a post hoc analysis of more than 17,000 patients enrolled in the DECLARE-TIMI 58 cardiovascular outcome trial of dapagliflozin (Farxiga), which showed a 19% relative decrease in the rate of incident AFib or atrial flutter events during a median 4.2 year follow-up.

Other prior reports that found a reduced incidence of AFib events linked with SGLT2 inhibitor treatment include a 2020 meta-analysis based on data from more than 38,000 patients with type 2 diabetes enrolled in any of 16 randomized, controlled trials, which found a 24% relative risk reduction. And an as-yet unpublished report from researchers at the University of Rochester (N.Y.) and their associates presented in November 2021 at the annual scientific sessions of the American Heart Association that documented a significant 24% relative risk reduction in incident AFib events linked to SGLT2 inhibitor treatment in a prospective study of 13,890 patients at several hospitals in Israel or the United States.

Evidence 'Convincing' in Totality

Dr Silvio E. Inzucchi

The accumulated evidence for a reduced incidence of AFib when patients were on treatment with an SGLT2 inhibitor are "convincing because it's real world data that complements what we know from clinical trials," commented Silvio E. Inzucchi, MD, professor of medicine at Yale University and director of the Yale Medicine Diabetes Center in New Haven, Conn., who was not involved with the study.

"If these drugs reduce heart failure, they may also reduce AFib. Heart failure patients easily slip into AFib," he noted in an interview, but added that "I don't think this explains all cases" of the reduced AFib incidence.

Patorno offered a few other possible mechanisms for the observed effect. The class may work by reducing blood pressure, weight, inflammation, and oxidative stress, mitochondrial dysfunction, atrial remodeling, and AFib susceptibility. These agents are also known to cause natriuresis and diuresis, which could reduce atrial dilation, a mechanism that again relates the AFib effect to the better documented reduction in acute heart failure exacerbations.

"With the diuretic effect, we'd expect less overload at the atrium and less dilation, and the same mechanism would reduce heart failure," she said in an interview.

"If you reduce preload and afterload you may reduce stress on the ventricle and reduce atrial stretch, and that might have a significant effect on atrial arrhythmia," agreed Inzucchi.

EMPRISE Produces More Real-World Evidence

A pair of additional reports at the meeting that Patorno coauthored provided real-world evidence supporting the dramatic heart failure benefit of the SGLT2 inhibitor empagliflozin (Jardiance) in U.S. patients with type 2 diabetes, compared with alternative drug classes. The EMPRISE study used data from the Medicare, Optum Clinformatics, and MarketScan databases during the period from August 2014, when empagliflozin became available, to September 2019. The study used more than 140 variables to match patients treated with either empagliflozin or a comparator agent.

The results showed that, in an analysis of more than 130,000 matched pairs, treatment with empagliflozin was linked to a significant 30% reduction in the incidence of hospitalization for heart failure, compared with patients treated with a GLP-1 receptor agonist. Analysis of more than 116,000 matched pairs of patients showed that treatment with empagliflozin linked with a significant 29%-50% reduced rate of hospitalization for heart failure, compared with matched patients treated with a DPP4 inhibitor.

These findings "add to the pool of information" on the efficacy of agents from the SGLT2 inhibitor class, Patorno said in an interview. "We wanted to look at the full range of patients with type 2 diabetes who we see in practice," rather than the more selected group of patients enrolled in randomized trials.

SGLT2 Inhibitor Use Lags Even When Cost Isn't an Issue

Despite all the accumulated evidence for efficacy and safety of the class, usage remains low, Julio A. Lamprea-Montealegre, MD, PhD, a cardiologist at the University of California, San Francisco, reported in a separate talk at the meeting. The study he presented examined records for 1,319,500 adults with type 2 diabetes managed in the VA Healthcare System during 2019 and 2020. Despite being in a system that "removes the influence of cost," just 10% of these patients received treatment with an SGLT2 inhibitor, and 7% received treatment with a GLP-1 receptor agonist.

Notably, his analysis further showed that treatment with an SGLT2 inhibitor was especially depressed among patients with an estimated glomerular filtration rate (eGFR) of 30-44 mL/min per 1.73m2. In this subgroup, usage of a drug from this class was at two-thirds of the rate, compared with patients with an eGFR of at least 90 mL/min per 1.73m2. His findings also documented lower rates of use in patients with higher risk for atherosclerotic cardiovascular disease. Lamprea-Montealegre called this a "treatment paradox," in which patients likely to get the most benefit from an SGLT2 inhibitor were also less likely to actually receive it.

While his findings from the VA System suggest that drug cost is not the only factor driving underuse, the high price set for the SGLT2 inhibitor drugs that all currently remain on U.S. patents is widely considered an important factor.

"There is a big problem of affordability," said Patorno.

"SGLT2 inhibitors should probably be first-line therapy" for many patients with type 2 diabetes, said Inzucchi. "The only thing holding it back is cost," a situation that he hopes will dramatically shift once agents from this class become generic and have substantially lower price tags.

The EMPRISE study received funding from Boehringer Ingelheim, the company that markets empagliflozin (Jardiance). Patorno had no relevant commercial disclosures. Inzucchi is an adviser to Abbott Diagnostics, Esperion Therapeutics, and vTv Therapeutics, a consultant to Merck and Pfizer, and has other relationships with AstraZeneca, Boehringer Ingelheim, Lexicon, and Novo Nordisk. Lamprea-Montealegre had received research funding from Bayer.

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