FRANKFURT (Reuters) - Fresenius Medical Care (>> Fresenius Medical Care AG & Co. KGaA), the world's largest dialysis provider, is looking for opportunities to grow in Europe and Asia as it feels the limits to growth in its largest market, the United States, its chief executive told Reuters in an interview.

FMC faces the twin challenge of antitrust limits to doing more U.S. deals coupled with a stricter Medicare reimbursement regime introduced in 2014 that forced it to slash costs.

"When you are as large as we are in our core business in the U.S., you can rarely buy anything and keep it all. Therefore, we are mainly looking for M&A outside of the U.S.," said Chief Executive Rice Powell.

FMC, which is indirectly controlled by a German charitable trust, operates more than one in three dialysis treatment centers in the United States.

Another response by FMC to the barriers to growth at its core U.S. dialysis business has been to branch out into related areas of care coordinating a range of treatments that dialysis patients typically need like cardiovascular and diabetes care.

The group last year laid out a plan to build a $5 billion care-coordination business by 2020 to offer a wider range of care for the chronically ill as part of an initiative to almost double group sales to $28 billion by then.

FMC, which derives about two-thirds of its sales from North America, in 2014 bought up a number of healthcare services companies, seeking to offer bundled treatments for kidney and cardiovascular disease.

To contain costs and ensure quality, regulators in the United States and elsewhere are keen for healthcare providers to organize the complex care of chronically ill patients for fixed-rate payments.

But even this campaign, underpinned by a slew of smaller deals in 2014, could be running out of steam because U.S. assets have become too expensive.

Powell indicated the $5 billion goal could prove too ambitious because U.S. deal targets were scarce, saying he was comfortable with its current assets putting it on track to have $3.5-$3.6 billion in care coordination revenues by 2020.

The $28 billion overall target, however, was well in place.

"Some of the valuations of businesses coming out of private equity don't make sense today for us to pursue," Powell said, giving the $1.6 billion acquisition of IPC Healthcare (>> IPC Healthcare Inc) by Team Health Holdings (>> Team Health Holdings LLC) as an example.

"We do not get deal fever at FMC. We are very comfortable with the asset base we have. We'll acquire something opportunistically," he said.

In care coordination too, growth is easier to find outside the U.S., such as Germany or Eastern Europe.

In Germany, procedures traditionally carried out in hospital such as treating infected injection sites are being moved to outpatient treatment centers that combine dialysis, cardiology and diabetology. A similar trend could be seen in eastern Europe, Powell said.

"We are in 23 of these types of arrangements in Germany. Those are the kind of things that we are seeing as potential opportunities to look at for care coordination in the international segment."

(Reporting by Ludwig Burger; Editing by Georgina Prodhan and Susan Thomas)

By Ludwig Burger and Andreas Kröner