A new study shows something many healthcare patients know all too well: hospitals are charging significant premiums on some of the most-used prescription drugs.

In a new study of 34 hospital systems, Wall Street firm AllianceBernstein found that the average drug prices in a hospital are three to seven times higher than what Medicare charges for the same medication, according to Axios, which obtained a copy of the study. Academic hospitals, which provide care and also train new doctors, had the highest markups on medications. AllianceBernstein also found that generic drug prices at all the hospital systems tended to be higher than brand-name medications.

The data comes as lawmakers, including those on both sides of the aisle and President Donald Trump, have called on the health care industry to reduce their drug prices. Patients, already dealing with rising health insurance and care costs, have at times buckled under the high price for critical drugs. Their inability in some cases to afford those drugs has forced those people to choose between buying the potentially life-saving medication or not, putting their health at risk.

Meanwhile, already cash-strapped hospitals are seeking ways to boost revenue, and charging more for medication is one of the ways they can do that.

Within the AllianceBernstein study, an unnamed CEO at a pharmaceutical company said that prices on oncology drugs, in particular, need to remain high. If they didn’t, the person said, “every hospital in the country will go broke.”