The information in this article is from HCUPnet, an online query system that provides access to health statistics and information on hospital stays from the Healthcare Cost and Utilization Project (HCUP) sponsored by the Agency for Healthcare Research and Quality (AHRQ). This project includes the largest set of publicly available databases on all patients in the United States, regardless of type of insurance or whether the patients had insurance. To access HCUPnet, go to http://hcup.ahrq.gov/HCUPnet.asp.

Preferred provider organization (PPO)-type plans, the most common type of health insurance that US employers offer their workers, are increasing in popularity even though their costs are rising faster than those of health maintenance organization (HMO)-type plans, according to a survey by the Agency for Healthcare Research and Quality (AHRQ).

PPO-type plans, which allow enrollees to obtain care from providers not in their networks but at higher out-of-pocket cost, have always been more expensive than the more restrictive HMO-type plans. These latter plans traditionally only cover care obtained from their providers.

AHRQ found that between 1996 and 2004, the percentage of employers offering PPO-type plans increased from 55.1% to 69.2%, whereas the percentage offering the less expensive HMO-type plans only increased from 32.4% to 36.2%.

By 2004 -- the most current AHRQ data available -- the average annual premium for single coverage under an HMO-type plan had reached $3492, compared with $3791 for a PPO-type plan.