The cost of medical care for people in employer-sponsored health plans rose at an annualized rate of 3.8 percent in the first quarter of 2011, according to the Thomson Reuters Healthcare Spending Index for Private Insurance.

A year earlier, in the period ending with the first quarter of 2010, the rate was 6.3 percent.

The index, which measures historical and current levels of per capita healthcare spending for people with employer-sponsored coverage, provides a benchmark measure of healthcare inflation.

It also tracks key components such as hospital care, physician services, and prescription drugs. Hospital costs showed the steepest growth in the Q1 2011 report, increasing 5.9 percent annually. Physician costs reflected a 3.2 percent year-over-year hike, and drug costs increased 0.3 percent.

"On both year-over-year and quarter-to-quarter bases, the rate of increase seems to be leveling off," saidGary Pickens, chief research officer at the Thomson Reuters Center for Healthcare Analytics. "These numbers will be a key indicator to watch as more elements of the healthcare reform legislation take effect."