Hospital prices are the main driver of U.S. healthcare spending inflation, and that trend should direct any policy changes going forward, according to a new study. 

For inpatient care, hospital prices grew 42% from 2007 to 2014 while physician prices rose 18%, according to researchers who studied the Health Care Cost Institute’s claims data for people with employer-sponsored insurance from Aetna, Humana and UnitedHealthcare Group. Similarly, for hospital-based outpatient care, hospital prices increased 25% while physician prices grew 6%, the new Health Affairs study found.