RT Journal
A1 Baker LC
T1 ASsociation of managed care market share and health expenditures for fee-for-service medicare patients
JF JAMA
JO JAMA
YR 1999
FD February 3
VO 281
IS 5
SP 432
OP 437
DO 10.1001/jama.281.5.432
UL http://dx.doi.org/10.1001/jama.281.5.432
AB Context 
                  Managed care has the potential to transform
fundamentally the structure and functioning of the entire health care
system, including the care provided to patients who are not enrolled in
managed care plans.Objective 
                  To determine whether increasing health maintenance
organization (HMO) market share is associated with decreased
expenditures for the care of patients covered by Medicare's
traditional fee-for-service plan, a group cared for well outside the
boundaries of managed care.Design and Setting 
                  Data from the Health Care Financing
Administration were used to compare expenditures for the care of
Medicare fee-for-service beneficiaries for 802 market areas,
representing the entire United States, for 1990 to 1994. These data
were matched with data on system-wide (Medicare and non-Medicare) HMO
market share in these areas.Patients 
                  All fee-for-service Medicare beneficiaries (1990-1994)
except for those with end-stage renal disease.Main Outcome Measure 
                  Average fee-for-service expenditure per
fee-for-service Medicare beneficiary by market area.Results 
                  In a regression model, increases in system-wide HMO market
share were associated with declines in both Part A and Part B
fee-for-service expenditures per Medicare beneficiary
(P<.001). Increases from 10% market share to 20% market
share were associated with 2.0% decreases in Part A fee-for-service
expenditures and 1.5% decreases in Part B fee-for-service
expenditures.Conclusions 
                  Managed care can have widespread effects on the health
care system. Health care for individuals who are not covered by managed
care organizations can be influenced by the presence of managed care.
Lower expenditures in areas with high HMO market shares may indicate
that traditional Medicare beneficiaries in areas with high market
shares received fewer or less intensive services than traditional
Medicare beneficiaries in other areas.