Aug 7 (Reuters) -

U.S. Senators Ron Wyden and Elizabeth Warren are launching

an investigation into UnitedHealth Group ( UNH ) related to

allegations that the company secretly paid nursing homes

thousands in bonuses to help slash hospital transfers for ailing

residents.

In a letter dated August 6 to UnitedHealth ( UNH ) CEO Stephen

Hemsley, the senators called on the healthcare conglomerate to

provide detailed information about its reported incentive

programming and its impact on residents.

The company in July publicly confirmed it was under

investigation by the U.S. Department of Justice and said it was

complying with both criminal and civil requests from the federal

agency over its Medicare business, a U.S. government program

that covers medical costs for individuals aged 65 and older and

those with disabilities.

The senators have sought responses by September 8 about the

company's hospitalization policies, directives related to care

planning for nursing home residents enrolled in their

institutional special needs plans, marketing practices related

to those plans and federal oversight related to them.

In May, the UK's Guardian newspaper reported the company

made secret payments to nursing homes, as part of a series of

cost-cutting tactics that saved the company millions, but at

times risked residents' health, citing an investigation carried

out by the newspaper.

"Any attempt to take advantage of vulnerable nursing

home residents is unacceptable, especially to pad a for-profit

insurance company's revenues," the senators said in the letter.

At that time, UnitedHealth ( UNH ) had said the U.S. Department of

Justice had investigated those allegations, interviewed

witnesses, and obtained thousands of documents that demonstrated

the significant factual inaccuracies in the allegations.

UnitedHealth ( UNH ) did not immediately respond to a Reuters

request for comment when contacted on Thursday.