In Reply: We agree with Dr Ho that the absence
of information on patients enrolled in Medicare managed care plans in the
database used in our study represents a potential methodological limitation.
However, we do not believe that the potential impact is as marked as Ho suggests.
First, the difference in managed care penetration between states with
continuous CON regulation and no CON regulation cited by Ho (26% vs 18%, respectively)
is not enough to eliminate the dramatic difference in mean annual hospital
volumes for CABG surgery in the 2 groups (191 vs 104, respectively). Even
if rates of CABG surgery were the same among managed care and traditional
fee-for-service enrollees, mean hospital volumes would still be roughly 70%
higher in states with continuous CON. However, the true impact of the missing
managed care data is likely to be less, given that managed care enrollees
are younger and healthier than fee-for-service enrollees,1 and
are, therefore, likely to have lower rates of CABG.
Vaughan-Sarrazin M, Rosenthal GE. Certificate of Need Regulations and Hospital Mortality. JAMA. 2003;289(5):551. doi:10.1001/jama.289.5.551-a