Private insurance claims data also show increased spending on HOPD services is playing a major role in overall spending growth on the publicly and privately insured because of increases in both prices and volume.

Using private insurance claims data for about 590,000 active and retired nonelderly autoworkers and their dependents, the Center for Studying Health System Change found that the average price for magnetic resonance imaging (MRI) of a knee was about $900 in hospital outpatient departments compared to about $600 in physician offices or freestanding imaging centers. Likewise, the average hospital outpatient department price for a basic colonoscopy was $1,383 compared to $625 in community settings.

A recent study published in the American Journal of Managed Care examined the price differential for individuals with employer-sponsored insurance by site of care for 7 commonly performed services at the national and regional level. Across all 7 services, prices at an HOPD were statistically significantly higher than payments to a physician office, ranging in 2013 from 21 percent more for an office visit to 258 percent more for chest radiography. The increase in the price differentials, combined with a shift in volume in favor of hospital outpatient departments, was associated with a 44 percent increase in total spending between 2008 and 2013.