NEW YORK, June 2 (Reuters) - UnitedHealth Group's ( UNH )

new CEO Steve Hemsley on Monday vowed to earn back

shareholder trust after its recent earnings shortfall, saying

the company was examining its approaches to medical cost trends

and how it forecasts future performance.

Hemsley replaced Andrew Witty as chief executive in May,

following the healthcare company's first earnings miss since

2008. Along with the appointment, UnitedHealth ( UNH ) suspended its

earnings outlook, as it weighed higher-than-expected costs in

its Medicare Advantage unit for adults 65 and older and people

with disabilities.

"We are well aware we have not fulfilled your expectations

or our own. We apologize for that performance, and we're humbly

determined to earn back your trust and your confidence," Hemsley

said at the company's annual shareholder meeting.

Hemsley said the company will factor in higher cost of care

into its private insurance plans and next year's Medicare

Advantage plans.

He also said UnitedHealth ( UNH ) will review its practices across

its businesses. UnitedHealth Group ( UNH ) operates pharmacy benefit

manager Optum Rx and health insurer UnitedHealthcare.