Df. Cox et C. Hogan, BIASED SELECTION AND MEDICARE HMOS - ANALYSIS OF THE 1989-1994 EXPERIENCE, Medical care research and review, 54(3), 1997, pp. 259-274
This article presents the results of an analysis of the preenrollment
and postdisenrollment experiences of Medicare-risk HMO enrollees. The
results indicate that in the 6 months prior to their enrollment, new H
MO enrollees use on average 37 percent fewer services than do benefici
aries in traditional fee-for-service Medicare. Furthermore, HMO disenr
ollees use 60 percent more services in the six months after disenrollm
ent than do fee-for-service beneficiaries. Finally, new enrollees had
relatively lower chronic-condition expenditures and mortality rates, w
hereas disenrollees had higher values for both. These findings suggest
that the overall results, in part, reflect permanent differences betw
een the HMO and fee-for-service Medicare populations. Moving to an ann
ual enrollment with a 90-day cooling-off period appears to be a reason
able approach to addressing these differences in enrollees.