DSI Renal, formed last year, has gobbled up 54 more dialysis clinics — making it the fourth largest provider in the nation.

The deal, financial terms of which were not disclosed, more than doubles the size of the locally based company.

“This acquisition is transformative for DSI in that we are establishing a larger, national focus and footprint,” said CEO Craig Goguen. “On a local level, we’re creating jobs that will bolster Nashville’s economy, and we’re also helping to foster competition in markets across the country for thousands of people who rely on clinics like ours to provide life-saving dialysis treatment.”

The deal, part of a spinout from a larger deal by German dialysis provider Fresenius, is similar to the one that resulted in the formation of DSI last year. Fresenius, in acquiring Liberty Dialysis Holdings last week, was required by the Federal Trade Commission to sell the clinics. Last year, DSI, in its current form (also known as Dialysis Newco), was born of such a requirement.

DaVita bought DSI for $690 million. Concerned over competition issues in various markets where DSI had clinics, the FTC eventually required that DaVita sell off 29 clinics to Dialysis Newco, which now operates under the old moniker.

Though terms of the deal announced today are not being disclosed, as a matter of comparison, the 29 clinics in the DaVita deal amounted to $91 million.

DSI is backed by venture capital outfits New Enterprise Associates and Frazier Healthcare.