NEJM CATALYST:

"The concentration of most U.S. health care spending in a small proportion of individuals is well documented. The notion that high health care spending only affects a small portion of people in a given year is particularly relevant to the ongoing policy debate about how to make health insurance affordable for all, while accommodating people with complex health care needs and accompanying higher costs. The distribution of health care spending is directly related to the solvency of insurance markets in which adverse selection may occur, and whether models like high-risk pools and reinsurance can be effective stabilization tools.

To better understand the patterns of spending for higher-risk enrollees, the Health Care Cost Institute studied the distribution of health care spending among commercially insured individuals and how their spending changed over time. Specifically, we analyzed the annual health care spending of more than 9 million individuals under the age of 65 in each pair of years from 2008 to 2015. Because people may change insurers over time, within each pair of years we limited our sample to people with continuous enrollment and prescription drug coverage for the full 2 years. We found that top spenders (the top 5%) account for a growing share of health care spending, and there is consistent and substantial turnover among these top spenders."