May 20 (Reuters) - UnitedHealth ( UNH ) said on Monday

its unit OptumRx would offer a new pricing model, starting next

year, to help manage insurers' costs for drugs.

The new model, Optum Rx Clear Trend Guarantee, will provide

value-based pricing of drugs per member combining the cost of

these medicines from various sources such as retail pharmacy,

home delivery, specialty drug and rebates.

Under value-based pricing models, insurers, pharmaceutical

companies and the middlemen, which include pharmacy benefit

managers (PBMs) like OptumRx, agree to link payment for medicine

to the overall outcome for patients.

The new model adds to OptumRx's announcements of other

measures to offer transparent pricing of drugs last year and

comes amid increased scrutiny into the role of PBMs in

ballooning healthcare costs in the United States.

Currently, out-of-pocket drug prices are decided by a

complex, multi-tiered network including insurers, drugmakers,

pharmacies and PBMs, resulting in ambiguity around fees and

markups to the original cost of the drug.

PBMs handle prescription drug benefits for health insurance

companies, large employers and Medicare prescription drug plans

- a group often referred to as payers.

OptumRx's new model will be effective at the same time as

TrueCost, which was announced by CVS' PBM unit, Caremark, to

offer clients more visibility into prescription drug pricing and

administrative fees.