Objective. To compare adjusted mortality rates of TEFRA-risk HMO enrollees
and disenrollees with rates of beneficiaries enrolled in the Medicare fee-f
or-service sector (FFS), and to compare the time until death for decedents
in these three groups.
Data Source. Data are from the 124 counties with the largest TEFRA-risk HMO
enrollment using 1993-1994 Medicare Denominator files for beneficiaries en
rolled in the FFS and TEFRA-risk HMO sectors.
Study Design. A retrospective study that tracks the mortality rates and tim
e until death of a random sample of 1,240,120 Medicare beneficiaries in the
FFS sector and 1,526,502 enrollees in HMOs between April 1, 1993 and April
1, 1994. A total of 58,201 beneficiaries switched from an HMO to the FFS s
ector and were analyzed separately.
Principal Findings. HMO enrollees have lower relative odds of mortality tha
n a comparable group of FFS beneficiaries. Conversely, HMO disenrollees hav
e higher relative odds of mortality than comparable FFS beneficiaries. Amon
g decedents in the three groups, HMO enrollees lived longer than FFS benefi
ciaries, who in turn lived longer than HMO disenrollees.
Conclusions. Medicare TEFRA-risk HMO enrollees appear to be, on average, he
althier than beneficiaries enrolled in the FFS sector, who appear to be in
turn healthier than HMO disenrollees. These health status differences persi
st, even after controlling for beneficiary demographics and county-level va
riables that might confound the relationship between mortality and the insu