Because we differentiated HMOs into group/staff and independent practice association (IPA) model type, the 1.5 percent of HMO Medicare beneficiaries who could not be matched to a specific Medicare risk HMO
were dropped (Gabel 1997).
One-quarter of those people--or 17 percent of all enrollees--were enrolled in a risk HMO
during the year, and the other three-quarters remained in the Medicare FFS Program.
Studies have shown that a high Medicare capitation rate is an important predictor of capitated risk HMO
enrollment in Medicare (Adamache & Rossiter 1985; Porell & Wallack 1990).
Less than 10 percent of the disabled are in a Medicare risk HMO
and only 5 percent have a medigap plan.
Approximately 5 percent of individuals in the 1993 sample were enrolled in a Medicare risk HMO
for the entire year, while 95 percent were in FFS settings for the entire year (Table 4).
By 1999 there were over 6 million Medicare risk HMO
members--a nearly 500-percent increase from 1991--comprising 17 percent of the Medicare population.
In 1997 alone, Medicare risk HMO
enrollment has growth by approximately 100,000 per month.
Patients diagnosed in 1985 or at age 65 or 66, or who had previous enrollment in a risk HMO
plan, had incomplete comorbidity data from Medicare claims in the two years prior to diagnosis (n = 4,554).
Between December 1994 and December 1998, Medicare risk HMO
enrollment nearly tripled, rising to 6.1 million beneficiaries, or over 15 percent of the Medicare population.
Prescription Drug Spending for Medicare Beneficiaries: 1995 Total Payments Percent Source of Payment in Thousands Distribution Total $22,020,930 100.0 Out-of-Pocket 11,106,552 50.4 Covered Persons 5,573,660 25.3 Non-Covered persons 5,532,892 25.1 Third-Party Payments 10,914,379 49.6 Medicare Risk HMO
775,166 3.5 Medicaid 2,365,024 10.7 Employer-Sponsored(1) 5,494,552 25.0 Individually Purchased 681,014 3.1 All Other(2) 1,598,622 7.3
The number of Medicare beneficiaries participating in the risk program has continued to show moderate growth, to the point where 1 in 20 beneficiaries are in a risk HMO
. Following a high growth rate in the early years of the program, rates of enrollment growth in Medicare moderated but were still higher than rates of enrollment growth in all HMOs.
The seven study States (California, Connecticut, Florida, Georgia, Illinois, Massachusetts, and Minnesota) were chosen to be representative of States with high TEFRA risk HMO
enrollment and/or diverse county sizes.