The impact of the Medicaid healthcare-associated condition program on mediastinitis following coronary artery bypass graft

OBJECTIVE
In 2012, the Centers for Medicare and Medicaid Services expanded a 2008 program that eliminated additional Medicare payment for mediastinitis following coronary artery bypass graft (CABG) to include Medicaid. We aimed to evaluate the impact of this Medicaid program on mediastinitis rates reported by the National Healthcare Safety Network (NHSN) compared with the rates of a condition not targeted by the program, deep-space surgical site infection (SSI) after knee replacement.

DESIGN
Interrupted time series with comparison group.

METHODS
We included surveillance data from nonfederal acute-care hospitals participating in the NHSN and reporting CABG or knee replacement outcomes from January 2009 through June 2017. We examined the Medicaid program’s impact on NHSN-reported infection rates, adjusting for secular trends. The data analysis used generalized estimating equations with robust sandwich variance estimators.

RESULTS
During the study period, 196 study hospitals reported 273,984 CABGs to the NHSN, resulting in 970 mediastinitis cases (0.35%), and 294 hospitals reported 555,395 knee replacements, with 1,751 resultant deep-space SSIs (0.32%). There was no significant change in incidence of either condition during the study. Mediastinitis models showed no effect of the 2012 Medicaid program on either secular trend during the postprogram versus preprogram periods (P=.70) or an immediate program effect (P=.83). Results were similar in sensitivity analyses when adjusting for hospital characteristics, restricting to hospitals with consistent NHSN reporting or incorporating a program implementation roll-in period. Knee replacement models also showed no program effect.

CONCLUSIONS
The 2012 Medicaid program to eliminate additional payments for mediastinitis following CABG had no impact on reported mediastinitis rates.