High government debt is seen as stoking inflation, research shows.

The company said that Mr. Witty had left the job for personal reasons. Stephen Hemsley, the company’s executive chairman, will replace him.

Pushback against Elon Musk’s latest demand to government employees reveals potential limits to his harsh approach to management and cost-cutting.

Patient advocates hope Dr. Michelle Tarver will lead the agency to focus more on safety and less on rapid approvals.