Drug May Reduce COVID-19 Mortality Rates for Diabetic Patients, Study by HMS Professor Finds

The drug sitagliptin may reduce mortality rates for diabetic patients hospitalized with COVID-19, an observational study led by Paulo Fiorina, assistant professor of pediatrics at Harvard Medical School, suggests.

Sitagliptin — a drug approved by the Food and Drug Administration — works to lower blood sugar in patients with type 2 diabetes by blocking the receptor for the enzyme DPP-4, increasing insulin production.

Patients with type 2 diabetes are at a higher risk of mortality from COVID-19 than nondiabetic patients, according to Fiorina. He attributed this difference in outcomes to the tendency for patients with type 2 diabetes to be more “fragile” and have other preconditions that could jeopardize their health.

“We're seeing that patients with type 2 diabetes are experiencing very bad outcomes — worse outcomes as compared to the standard population when they face COVID,” he said.

Researchers found patients with type 2 diabetes who received sitagliptin in addition to insulin had a lower mortality rate — 18 percent — than those who received just insulin, whose mortality rate was 37 percent.

The drug has been known to curb inflammation — an attribute Fiorina says may be the reason for its effectiveness against the coronavirus.

Fiorina and his team conducted the research — which involved seven hospitals in Italy during spring 2020 — as a retrospective observational study, which is considered a level below the gold standard of a randomized, placebo-controlled clinical experiment.

The study involved 338 patients who had both COVID-19 and type 2 diabetes. Of those patients, 169 served as the control group and received only insulin. Both insulin and sitagliptin were administered to the other 169 patients. The groups were matched by age and sex, the severity of the illness, use of other treatments, and other clinical characteristics.

In addition to reducing mortality rates, the study also found that patients treated with sitagliptin were less likely to need ventilation or intensive care.

Among the treatment group, there was an improvement in several “key outcomes,” Fiorina said.

“There was a greater number of patients discharged earlier and to a greater extent from a hospital,” Fiorina said. “120 people were discharged in the treatment group, as compared to 89 in the untreated group.”

Biomarkers for the patients in the treatment group also showed less inflammation and overall better wellbeing, he said.

Though Fiorina said he is confident in the results of the study, he added that researchers will still need to conduct more studies to more definitively assess the drug’s effectiveness.

“I'm kind of confident here on the result of the study for many reasons. First, the number of patients is not low,” he said. “And when you look at the data in each of the seven centers, they're very consistent.”

“We will need to run — and we are actually starting to run — the randomized double-blind study,” he added.

Fiorina said he speculates the drug could be effective in reducing mortality rates of nondiabetic patients as well.

“It's possible the benefit of the drug could be related to an anti-inflammatory effect and may be a reduction of viral entry,” Fiorina said. “If this is the case, there is a potential use for sitagliptin in nondiabetic patients.”

He also said the drug is inexpensive and safe to use.

“It's not expensive, so this can be used also in undeveloped countries. The patent is expiring on the drug, so everybody can have access to these patents — so this is very important for developing countries,” he said.

“There are no adverse effects reported with the use of this drug,” he added.

—Staff writer Taylor C. Peterman can be reached at taylor.peterman@thecrimson.com. Follow her on Twitter @taylorcpeterman.