But after 2004, per capita spending for the poorest quintile fell at a rate of $19.27 annually, or 3.7 percent over an eight-year period until 2012, the study found. At the same time, per capita health spending for members of the richest quintile sharply spiked, rising at a rate of $106.04 annually, or 19.7 percent over eight years.
Health spending by the middle three quintiles also grew, in contrast to what happened to the poor, but at a less dramatic rate — 12.5 percent during the same time period.
By the end of the eight-year period, in 2011, per capita health spending for the poorest quintile, adjusted for age and health status, was $4,074, Woolhandler said. Spending for the middle quintile was $4,647 per capita, she said. But health spending in the richest quintile was $5,817 per capita.
The divergence between income groups was due to changes in health spending among people under the age of 65, according to the study. Its authors noted that "the elderly of all incomes experienced similar, flat expenditure growth," with the poorest continuing to have the highest spending.
Woolhandler said the data doesn't reveal whether the poor, as a group, are getting too little in the way of health care, or whether the rich are getting too much as a group. Both scenarios are possible, but "we cannot tell," she said. However, the shift revealed by the study "cannot possibly be an efficient use of resources" by the health-care system.
"To be efficient, that has to track with need," Woolhandler said.
While people with worse health status had higher health-related spending, "shifts in health status did not explain the recent divergence in health expenditures among income groups."
Woolhandler noted that "poor men are living 15 years shorter lives [as a group] than rich men."
"And for the poorest women, they're living 10 years shorter than the wealthiest women," she said.