DOW JONES NEWSWIRES DaVita Inc. (DVA) said it has agreed to buy fellow dialysis-center operator DSI Renal Inc. for about $690 million, looking to expand itself geographically. DSI runs 106 dialysis centers that serve about 8,000 patients, and the company has yearly revenue of about $360 million. DaVita, meanwhile, runs or provides administrative services at nearly 1,600 dialysis facilities, serving about 124,000 patients. "This acquisition introduces us to several new geographies and makes us a more effective competitor in selected areas," said DaVita Chairman and Chief Executive Kent Thiry. "Through this acquisition, we will be able to bring the broader line of DaVita chronic kidney disease services to DSI patients." The acquisition is expected to close during the second or third quarter this year. DaVita's earnings have grown in recent quarters on increasing demand. The company in November said its third-quarter profit increased 7.6% as revenue climbed. Shares of DaVita closed at $74.86 on Thursday and were inactive premarket. The stock has risen 25% in the past year. -By Nathan Becker, Dow Jones Newswires; 212-416-2855; nathan.becker@dowjones.com