U.S. Sen. Susan Collins, R-Maine, is leading a group of 26 senators who signed a letter Tuesday to a top federal health official questioning whether hospital patient satisfaction surveys on pain control should be tied to federal funding.

The letter to Sylvia Burwell, secretary of the U.S. Department of Health and Human Services, requests a “robust examination” of the surveys, which currently are a factor in a complex Medicare funding formula that was designed to reward hospitals for quality care.

But the letter questions whether pain management should be part of the equation. Four of five new heroin users were first addicted to prescription opioids, according to the National Council on Drug and Alcohol Abuse. Maine has seen a surge in heroin usage and fatal overdoses over the past few years, including 71 fatal heroin overdoses in the first nine months of 2015.

DHHS has already been evaluating the patient surveys, according to the letter.

“As we take steps to reward high quality care in the Medicare program, it is critical that we correctly measure the quality we are rewarding,” said the letter, which was also signed by U.S. Sen. Angus King, I-Maine, and New Hampshire’s two senators, Democrat Jeanne Shaheen and Republican Kelly Ayotte. “Currently, there is no objective diagnostic method that can validate or quantify pain. Development of such a measure would surely be a worthwhile endeavor.

“In the meantime, however, we are concerned that the current evaluation system may inappropriately penalize hospitals and pressure physicians who, in the exercise of medical judgment, opt to limit opioid pain relievers to certain patients and instead reward those who prescribe opioids more frequently,” the letter added.

In an interview with the Portland Press Herald last week as she was working with her staff to prepare the letter, Collins said she wonders whether the surveys unintentionally contributed to the heroin epidemic.

“I believe the pendulum has swung too far in favor of controlling pain, although I am not suggesting that the pain people experience is not real,” Collins said.

But Collins said the surveys may have led to the overprescription of opioids.

Maine Human Services Commissioner raised similar concerns in a letter to Burwell in November.

“Ultimately, we believe rewording the pain management questions to better reflect pain management versus elimination will benefit clinicians and the patients they care for,” Mayhew wrote.

There does not appear to be much research on the topic, but a 2012 survey of doctors by the South Carolina Medical Association reported that nearly 50 percent of doctors improperly prescribed narcotics due to pressure caused by patient satisfaction surveys, according to a Forbes magazine article.

Dr. Stephen Hull, medical director of pain management at Mercy Hospital in Portland, said the surveys are counterproductive and “a disincentive to say no” to prescribing opioids. Hull said when doctors know federal funding could be tied to the surveys, they may go against their better judgment to satisfy patients.

“They’re going to pull out their prescription pad and write up a prescription for what the patient wants,” Hull said.

Hull said research has concluded that opioids should not be prescribed for chronic pain, and that they should only be prescribed in limited circumstances to control acute pain.

“We should not be so focused on pain, but rather on how well the person is able to function,” Hull said.

The senators’ letter to Burwell said the United States is still prescribing far too many opioids.

“It is alarming that Americans consume opioids at a greater rate than any other nation, including twice as many opioids per capita as Canada. Such an ample supply of prescription opioids is subject to misuse and diversion, which has become one of the foremost public health challenges facing our nation,” the letter said.

Andrew MacLean, deputy executive vice president and general counsel of the Maine Medical Association, said the pain management questions should be scrutinized.

“I’ve just had conversations with several physicians in the last week and they were saying they felt pressured by patient satisfaction surveys,” MacLean said. “This type of inquiry would be helpful and we applaud the senator’s efforts.”

This story was updated at 9:15 a.m., Feb.10, to correct the title of Andrew MacLean.