Social Security beneficiaries may not be seeing an increase in their paid benefits for a third year in a row.

The lack of funding will impact millions of retired and disabled people in the United States.

A slight cost-of-living adjustment (COLA) is being projected by the government for Social Security benefits next year for the first time since 2009. However, rising Medicare costs will cancel out any increase in payments.

About 45 million people, or one in seven in the nation, receive both Medicare and Social Security. By law, beneficiaries have their Medicare Part B premiums, which cover doctor visits, deducted from their Social Security payments each month.

When Medicare premiums increase more than Social Security payments, millions living on fixed incomes don't get raises. However, they don�t get pay cuts either, because a provision prevents higher Part B premiums from reducing Social Security payments for most people.

David Certner of AARP estimates that as many as three-fourths of beneficiaries will have their entire Social Security increase gobbled up by rising Medicare premiums next year.

"You just don't have the words to say how much this impacts a person," said Joyce Trebilcock, a retired legal secretary.

Trebilcock, 65, said Social Security is her primary source of income. She receives $1,262 in Social Security payment each month, with more than $500 going to pay the mortgage.

"I've cut back on about everything I can, and I take the rest out of my savings," Trebilcock said. "Thank God I've got that. That's going to run out before long, at the rate I'm going. ... I have no idea what I'm going to do then."

Social Security recipients spend, on average, 9 percent of their benefits on Medicare Part B premiums, plus 3 percent on premiums for the Medicare prescription drug program.

"We could very well be entering a period where we're all stuck with flat benefits because of the growth in health care costs," said Mary Johnson, a policy analyst at The Senior Citizens League.

Social Security COLAs are determined each year by a government measure of inflation. When consumer prices go up, payments go up. When consumer prices fall, payments stay fixed until prices recover. There had been a COLA every year from 1975 through 2009.

Medicare Part B premiums must be set each year to cover 25 percent of program costs. They have remained at 2009 levels for about 75 percent of beneficiaries because there was no increase in Social Security. The 2009 premium levels, which are still paid by about three-fourths of beneficiaries, are $96.40 a month.

"That little raise helps us," said Estelle Jones, 66, of St. Paul, Minn. "Food, heating bills, water bill, all that stuff has gone up. ... All my medicines are very expensive, and every month I have to figure out how I am going to pay for them.