Disparities in SGLT2i Use: Patient Barriers or Physician Bias?

SGLT2 inhibitors have been shown to reduce cardiovascular events (including hospitalization for heart failure) and progression of nephropathy, not just in people with diabetes but also in those without. The use of these medications is increasing for multiple disease conditions because of benefits that extend beyond the antihyperglycemic aspect for which they were originally developed.

However, a recently published study suggests racial, gender, and socioeconomic disparities in SGLT2 inhibitor use in the United States. Using a large administrative database of inpatient, outpatient, and pharmacy private-payer claims of more than 17 million patients from all 50 states, the authors looked at patients with type 2 diabetes, excluding those without continuous insurance enrollment for at least 12 months before and at least 6 months after the study ended. Subgroup analyses were performed for patients with heart failure with reduced ejection fraction (HFrEF) and those with chronic kidney disease (CKD) stages 1-3. A total of 934,737 patients met the inclusion criteria.

The authors reported an increase in prescriptions from 4% in 2015 to 12% in 2019. Overall, patients not started on SGLT2 inhibitors were more likely to be older and female. Those with median household incomes > $50,000 were more likely to be on these agents than those with income < $50,000. More patients with a commercial insurance group (68%) were prescribed SGLT2 inhibitors compared with those on Medicare (32%).

Patients were two to three times more likely to be on an SGLT2 inhibitor if they had one or more visits to an endocrinologist in the past 12 months, compared with those who had not seen one. Black patients had a 17% lower relative risk of being prescribed an SGLT2 inhibitor compared with White patients. History of myocardial infarction, cerebrovascular accident, or CKD did not increase the likelihood of prescription, and concurrent history of HFrEF was paradoxically associated with a 17% lower relative risk likelihood of being prescribed an SGLT2 inhibitor.

Why the Difference?

The authors acknowledged that a study of this nature is unable to differentiate between prescriptions offered (illustrating biases in treatment strategies) vs prescriptions filled (illustrating barriers due to costs or perceived side effects). But this study still brings to light several important areas needing improvement within the healthcare system.

Patients who would derive the most benefit from SGLT2 inhibitors (those with atherosclerotic cardiovascular disease, HFrEF, CKD) are not yet being prescribed these medications. Considering that patients seeing a specialist (endocrinologist or cardiologist) were more likely to be on these medications, it is important to increase awareness of the cardioprotective/nephroprotective action of SGLT2 inhibitors among primary care healthcare professionals. This would considerably increase the overall benefit we could see at a population level, as not every patient is able to see a specialist.

Potential risks for recurrent genital mycotic infections and volume depletion might explain to some extent the lower prescribing rates in women and older individuals, respectively, but it is unknown whether these factors actually contributed, or what other reasons could have led to low rates of utilization in these subgroups.

Black patients are known to have higher rates of cardiovascular disease and nephropathy progression, yet these high-risk patients had low rates of SGLT2 inhibitor use even after correcting for those who were seen by specialists. This could be suggestive of inherent racism and implicit bias in medicine that needs to be corrected. This is all the more important in current times, with mortality of Black Americans now 2.2 times higher than that of White Americans.

Perhaps one of the most important barriers is cost and whether the benefits gained would outweigh spending. These medications are significantly expensive. A 1-month supply of empagliflozin for someone in the United States with no insurance would cost $548.54 out of pocket, plus additional pharmacy costs. Even with Medicare part D insurance, about 37% of patients may end up paying about $161 per month on average, with the cost varying depending on where the patient is in the "donut hole." This can make SGLT2 inhibitors prohibitively expensive and explains the disparity in prescribing according to insurance and household income.

However, healthcare systems can save thousands of dollars by utilizing this class of medications over other antihyperglycemic agents because of reduced hospitalization and complication costs. The savings are particularly striking when considering patients with nephropathy in whom delayed progression to dialysis (as seen in the CREDENCE trial) can save healthcare systems more than half a million dollars for each patient whose renal replacement therapy is delayed.

SGLT2 inhibitors have proven their efficacy time and again for a variety of disease states, but studies like this show that there is a long way to go before the abundance of scientific literature translates into widespread use of disease-modifying medications, including in high-risk and minority groups, in the current practice of medicine.

Akshay B. Jain, MD, is a clinical endocrinologist who has practiced in three countries, focusing on mitigating the complications of diabetes and obesity. He is fluent in six languages and has spoken at more than 500 programs internationally.

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