Health insurer Humana (HUM) narrowed its third-quarter profit on Monday but raised its full-year outlook as newly announced acquisitions and medical claim reserves helped spark optimism.

The Louisville, Ky.-based company posted net earnings of $426 million, or $2.62 a share, compared with a year-earlier profit of $445 million, or $2.67.

Earnings were weighed down as people visited doctors more frequently and racked up insurance claims. Health-benefits companies fared relatively well during the recession as uncertainty pressured people to postpone non-emergency procedures.

While the results topped average analyst estimates of $2.05 in a Thomson Reuters poll and beat the company’s own estimate in a range of $2.00 to $2.10, Humana attributed some of the quarterly growth to the shifting of certain costs to the fourth quarter.

Revenue for the three months ended Sept. 30 climbed 3.8% to $9.65 million from $9.3 million a year ago, led by higher services and premiums revenue, but missed the Street’s view of $9.86 million.

“Our third-quarter results demonstrate that the issues which surfaced in the second quarter have stabilized,” Humana’s soon-to-be CEO Bruce Broussard said in a statement.

Shares of Humana fell more than 1% on Monday to $74.41.

Broussard is set to replace current chief executive Michael McCallister upon his retirement in January.

Humana also said on Monday that it has agreed to buy Metropolitan Health Networks (MDF) for $11.25 a share, a transaction valued at about $850 million, in an effort to boost its Medicare Advantage and Medicaid programs.

“Combined with existing capabilities in our CAC and Concentra medical centers, Humana will soon employ or have strategic investments in medical practices that include nearly 2,300 physicians nationwide.” Broussard said. “We believe our improving operations and continued Medicare membership growth, together with our integrated care delivery system investments, position Humana well for a dynamic future.”

Humana's Medicare Advantage program had more than 1.9 million members as of the end of September, an increase of about 298,400 members from last year. 

The company expects the deal to be modestly accretive to its fiscal 2013 earnings.

Humana raised its fiscal 2012 earnings guidance to a range of $7.25 to $7.35 a share for the period ended Dec. 31, up from an earlier forecast of $6.90 to $7.10, led by a stronger medical claims reserve and improved stand-alone Prescription Drug Plan results.

The consensus is calling for full-year earnings of $7.14.

Looking ahead to 2013, Humana projects earnings between $7.60 and $7.80 a share, below the Street’s view of $7.87.

Follow Jennifer Booton on Twitter at @Jbooton