NEW YORK, July 18 (Reuters) - UnitedHealth Group Chief Executive Officer Stephen Hemsley said on Tuesday that national and state healthcare policy are a possible drag on profit in 2018, as Republican lawmakers continue to disagree about how to repeal and replace the national health law known as Obamacare.

"Certainly, at this stage in the national conversation, speculation about any outcome here would be just that," Hemsley told Wall Street analyst during a conference call to discuss its second-quarter profits. (Reporting by Caroline Humer; Editing by Nick Zieminski)