Hospital price variation accounted for one-third of the difference in health spending in 19 communities, even after accounting for geographic differences in wages and rent, according to a report.

The report, by the Center for Studying Health System Change for the National Institute for Health Care Reform, looked at health spending for union autoworkers and dependents across seven states with similar health plans. Spending per person ranged from $4,500 to $9,000 with price accounting for 33% of the difference, according to the report by Chapin White, a senior researcher for the center.

Unexplained differences in the use of medical services accounted for another 18% of the variation in spending.

The study included medical claims for 218,000 autoworkers and their dependents across seven states. The communities were spread across seven states: Delaware, Illinois, Indiana, Michigan, Missouri, New York and Ohio.

Differences in health accounted for 37% of variation in spending and age and sex another 10%.

When compared with Medicare prices, the average autoworker health plan’s prices for hospital inpatient care were 55% higher. The average emergency room prices were double Medicare prices.