BY JON KAMP

Humana Inc.'s fourth-quarter earnings rose 86% amid an ongoing trend of rising membership and patients using health services lightly, and the company expects to continue bulking up by adding more senior customers this year.

Humana's earnings met analyst expectations for the quarter, although revenue was softer than expected. The Louisville, Ky., firm's full-year guidance also remains below analyst expectations, even though Humana raised its forecast based on stronger-than-expected enrollment increases for Medicare Advantage plans.

After a string of strong reports that helped push Humana shares to an all-time peak last month, expectations were running high, and the stock traded down ...