At a major tertiary care center, cardiologists prescribed only about 5% of all sodium-glucose cotransporter 2 inhibitors from 2013 to 2017, with no appreciable increase after the FDA expanded labeling for use of these agents for CV risk reduction, researchers reported in the Journal of the American College of Cardiology.
In a retrospective study, Muthiah Vaduganathan, MD, MPH, a fellow in cardiovascular medicine at Brigham and Women’s Hospital Heart and Vascular Center, and colleagues evaluated all first-time outpatient prescriptions of sodium-glucose cotransporter 2 (SGLT2) inhibitors, including canagliflozin (Invokana, Janssen Pharmaceuticals), dapagliflozin (Farxiga, AstraZeneca), empagliflozin (Jardiance, Boehringer Ingelheim) and ertugliflozin (Steglatro, Merck), from 2013 to 2017 across the Partners HealthCare system in Boston.
The researchers included data from 2013 when the first SGLT2 inhibitor — canagliflozin — received FDA approval through late 2017, which was 1 year after the FDA expanded the indication for empagliflozin to reduce CV risk. Most recently, in 2018 after the study concluded, the FDA also expanded the indication for canagliflozin.
“Three major CV outcomes trials have supported [the beneficial effects of SGLT2 inhibitors]. In fact, the FDA has added additional regulatory labels for empagliflozin and canagliflozin specifically for reducing CV risk,” Vaduganathan wrote in an email to Cardiology Today. “Cardiologists come across many patients with type 2 diabetes mellitus who may be eligible for this beneficial class of therapies. We undertook this study to explore prescriber patterns in the first 5 years since initial availability of these agents, and more specifically, to understand if cardiologists have been using these therapies in clinical practice.”
Low engagement among cardiologists
During the study period, 1,874 patients (median age, 62 years; 59.1% men; 76.5% white) were prescribed 1,991 SGLT2 inhibitors, including 117 who were switched from one SGLT2 inhibitor to another.
Of all SGLT2 inhibitor prescriptions, endocrinologists accounted for 40%, primary care physicians accounted for 23.1%, physicians from other specialties accounted for 18.6%, unclassified physicians accounted for 13.2% and cardiologists accounted for 5.1%. Switches from one SGLT2 inhibitor to another were most commonly initiated by endocrinologists (67.5%).
Results showed that prescribing rates remained low among cardiologists (4.5%), as compared with endocrinologists (45.4%) and PCPs (22.7%), even during the year after the addition of the CV indication for empagliflozin.
“We were surprised to see that this low rate of engagement [among cardiologists] did not change after broadening of the FDA labeling for empagliflozin. It was encouraging, however, to observe that many clinicians are thinking about this class of therapies, with over 2,000 mentions in the electronic health record, in patients who ultimately were not prescribed an SGLT2 inhibitor,” Vaduganathan said.
Canagliflozin accounted for 61.4% of SGLT2 prescriptions, empagliflozin for 32.4% and dapagliflozin for 6.1%. The FDA did not approve ertugliflozin until December 2017, and the drug had not yet been prescribed for any patients during the study period in the Partners HealthCare System.
Although canagliflozin was the most frequently prescribed SGLT2 inhibitor (78.9% to 100%) across quarters in 2013 to 2015, rates decreased after 2016. Additionally, in 2017, empagliflozin accounted for 57.5% of SGLT2 inhibitor prescriptions, whereas canagliflozin accounted for 37% of prescriptions.
The researchers noted that canagliflozin was most commonly prescribed during the study period, but was outstripped by empagliflozin after communications from the FDA.
“Our study suggests that clinical trial data and FDA communications have important implications on care patterns. For instance, we did observe a decline in overall SGLT2 inhibitor prescriptions after the FDA communication regarding the potential amputation risks with canagliflozin. In addition, we saw recent increases in empagliflozin prescription and declines in canagliflozin prescription after supportive clinical trial data from EMPA-REG OUTCOME,” Vaduganathan told Cardiology Today.
Several completed CV outcomes trials involving SGLT2 inhibitors are set to be released soon, including at the American Heart Association Scientific Sessions 2018, and their effect on prescribing patterns is not yet known, according to the researchers.
Vaduganathan noted, however, that further investigation is needed.
“This experience was limited to a multicenter tertiary care health system. We need to understand the use of emerging glucose-lowering therapies in various care settings, including in patients with limited health resources or low income,” he told Cardiology Today. – by Melissa Foster
For more information:
Muthiah Vaduganathan, MD, MPH, can be reached at firstname.lastname@example.org; Twitter: @mvaduganathan.
Disclosures: Vaduganathan reports he is supported by NIH/NCATS grants and he has served on advisory boards for AstraZeneca, Bayer AG and Baxter Healthcare. Please see the study for all other authors’ relevant financial disclosures.