Eli Lilly and Company LLY, +1.11% increased its U.S. revenue by 15% for the fourth-quarter, but the rise may have come partly at the expense of patients with diabetes.

The company reported the fourth-quarter revenue increase Thursday, with sales of Humalog insulin, a short-acting insulin used by consumers with Type I and Type II diabetes, leading the company’s U.S. pharmaceutical revenues with a 20% increase. That growth was “driven by higher realized prices, and, to a lesser extent, increased volume,” the company said.

Asked on the earnings call about the current debate over drug pricing, John Lechleiter, chief executive officer, said higher prices make sense because it helps the company fund the research needed to find better treatment methods or a cure.

“Yes, they (drugs) can be expensive, but disease is a lot more expensive,” Lechleiter, told analysts.

Other Eli Lilly price increases in the fourth-quarter included medications used to treat osteoporosis,a medication to treat attention deficit hyperactivity disorder, a blood thinner used to prevent blood clots and a medication for erectile dysfunction.

The company prices its drugs “based on the value” they bring “to patients, providers, payers, and society,” an Eli Lilly spokesperson told MarketWatch in emailed comments.

“This value-based approach considers cost savings that our medicine delivers compared to less effective or less safe treatment alternatives that might be available, as well as no treatment,” the spokesperson said.

So, patients have to pay more for their drugs because the alternatives aren’t safe?

Inflated drug pricing has become a major controversy this year and turned into a political hot potato for candidates on the presidential election campaign. Democratic candidate Hillary Clinton has made the issue a key part of her platform.

The subject made headlines after biotech investor Martin Shkreli, CEO of Turing Pharmaceuticals AG, raised the price of a drug that is used to fight a potentially life-threatening infection to $750 a pop from $13.50 on the grounds that he had an obligation to create more money for his shareholders, The Wall Street Journal reported.

Other companies, including Valeant Pharmaceuticals International Inc. US:VRX, have also been criticized for their drug pricing policies.

Shkreli, who was arrested in December on securities fraud charges that are not related to drug pricing, has been subpoenaed, along with the interim CEO of Valeant, by a congressional investigative committee.

Overall, the price increase in Eli Lilly’s pharmaceuticals lifted revenues by 3%, while volume added 7%. Read more about Eli Lilly’s results.

The company did not respond to questions on how much it raised prices.

On the call, Lechleiter said investments made by companies such as Eli Lilly eventually lead to lower-cost generic versions of a drug. But in the case of Humalog insulin, which is a biological drug and difficult to manufacture, a generic option doesn’t yet exist.

According to GoodRX, which compiles data from pharmacies and drug manufacturers, Humalog is the second-most popular insulin choice with a current maximum price of $472, making it the most expensive short-acting insulin on GoodRX’s list.

Type I diabetics are dependent on fast-acting insulins such as Humalog. (Full disclosure: This reporter uses Humalog insulin).

Shares of Eli Lily have fallen 6% in the past three months compared with the S&P 500’s fall of 10%.