The objective of this study is o examine comorbidity and therapy use rates in a Medicaid population with heart failure (HF), evaluate hospitalization risk as a function of comorbidity and therapy use, and assess the impact of modification on costs to the Medicaid program. It is a historical prospective cohort study. Claims were from adult enrollees in Maryland Medicaid (managed care organization or fee-for-service) diagnosed with HF between 2005 and 2009.