NU Online News Service, July 9, 11:59 a.m. – InterStudy Publications, St. Paul, Minn., says health maintenance organizations’ share of the U.S. health care market may be shrinking.

InterStudy researchers looked at changes in U.S. HMO enrollment between July 1, 1999, and July 1, 2000, for its latest regional health care market analysis.

The researchers found that HMO enrollment fell 0.7% in metropolitan areas, to 73 million, while total U.S. HMO enrollment fell 0.9%, to about 80 million.

HMOs covered the health of 32.4% of all residents of metropolitan areas July 1, 2000, down from 33.8% a year earlier. The pentration rate fell to 18.6%, from 19.1%, in the smaller markets, and to 36.5%, from 38%, in larger markets.

But InterStudy found that HMO enrollment grew by at least 100,000 in seven markets?Riverside-San Bernardino, in California; Newark, N.J.; San Diego; Pittsburgh; Sacramento, Calif.; San Francisco; and Oakland, Calif.