UnitedHealth's

(UNH) - Get Report

ability to add customers while reining in costs continued to pay dividends in the first quarter, sending earnings up 41% from a year ago.

The health maintenance organization earned $779 million, or $1.16 a share, in the quarter, compared with $554 million, or 88 cents a share, last year. Revenue jumped 34% from a year ago to $10.9 billion. Analysts were forecasting earnings of $1.13 a share on revenue of $11.2 billion.

For 2005, UnitedHealth said it currently expects to earn $4.85 to $4.90 a share. The Thomson First Call consensus estimate is $4.82 a share.

In the most recent first quarter, UnitedHealth said its health care services division added 95,000 customers, bringing the end-of-period total to more than 11 million. At the corporate level, operating costs fell by 130 basis points to 14.9% of revenue, while the consolidated operating margin was 11.5%, compared with 10.8% last year.

The company's consolidated medical care ratio, which measures medical expenses as a percentage of premiums, fell by 30 basis points to 78.9% in the quarter.

UnitedHealth's shares are up 43% over the last year, closing Wednesday at $95.96. In premarket Instinet trading, they added another 79 cents to $96.75.