Managed care plans not always better for preventive medicine, says UCSF study

By Kevin Boyd on January 10, 2000

Contrary to popular belief, managed care health plans generally do not give their patients more preventive medical services than non-managed care plans, says a new study from researchers at the University of California, San Francisco.  However, the researchers said, certain types of managed care plans score better than others, and have a clear advantage over non-managed care.

Most people, including those who study health care plans, take it for granted that managed care plans give customers greater access to preventive medicine, including immunizations, medical and nutrition counseling, and disease screening.  Several previous studies including a 1994 survey by Harold Luft, PhD, Director of UCSF’s Institute for Health Policy Studies, and Bob Miller, PhD, a UCSF associate professor at the Institute for Health and Aging, showed that HMO enrollees were consistently more likely to receive preventive services than people in non-managed care plans. 

But managed care has changed dramatically during the last decade, said Kathryn Phillips, PhD, lead author of the new study and an associate professor of health economics and health services research at UCSF’s School of Pharmacy and Institute for Health Policy Studies.  A far smaller percentage of people enrolled in managed care today are members of a “group/staff” managed care plan - one in which patients almost exclusively see doctors within the HMO.  In 1990, 40 percent were enrolled in this type of plan, whereas only 12 percent were in 1997.  Today, most patients use more open types of managed care plans, which “tend to be much more loosely managed,” and less centralized, Phillips said.

Phillips looked at the impact of these changes on use of preventive care. Working with other researchers, including Melanie Egorin, a UCSF doctoral student in sociology, she performed a meta-analysis of 18 studies from the 1990’s that compared preventive services in managed care versus non-managed care health plans. 

In 60 percent of these plan-to-plan comparisons, there was no difference in the use of preventive services.  “Managed care is not always better,” Phillips said.  This may have changed since the early 1990s because of the increasing numbers of non-traditional managed care plans, such as PPOs (Preferred Provider Organization), IPAs (Individual Practice Association), and network plans.  These plans may provide less preventive care than traditional HMO because of their less centralized structure, weaker relationships with plan doctors, and less frequent use of patient reminders, Phillips said.

Traditional group/staff managed care plans still had a clear advantage in the study, which appears in the January/February issue of the journal Health Affairs.  These plans provided more preventive services than non-managed care in 92 percent of the comparisons.  In group/staff plans, exclusive use of the plan’s doctors, many of whom are employed by the plan, makes it easier to establish clear guidelines for preventive care, and to make sure they are followed, Phillips said.

With so many types of managed care plans now available, Phillips recommends that consumers try to understand how their plan works and whether it is likely to give them the services they need.  One way to assess health plans is to look at health plan “report cards”, such as those published by the National Committee for Quality Assurance, she said. 

Co-investigators on the study included Susan Fernyak, director of the Communicable Disease Prevention Unit at the San Francisco Department of Public Health, Arnold Potosky, operations research analyst in the Division of Cancer Prevention and Control at the National Cancer Institute, Helen Halpin Schauffler, PhD, associate professor of health policy and director of the Center for Health and Public Policy Studies at the University of California, Berkeley, School of Public Health.