Retrospective claims database analysis to determine relationship between renin-angiotensin system agents, rehospitalization, and health care costs in patients with heart failure or myocardial infarction.

BACKGROUND: Heart failure (HF) and myocardial infarction (MI) cause considerable morbidity and mortality, but the outcomes and health care costs related to adherence to treatment guidelines for HF and MI are not fully understood.
OBJECTIVES: The aims of this study were as follows: (1) to determine the proportion of patients discharged from the hospital with a primary diagnosis of HF or MI who subsequently received prescriptions for American Heart Association/American College of Cardiology-recommended angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs), also referred to as renin-angiotensin system agents; (2) to investigate the relationship between adherence to and persistence with ACEIs/ARBs and risk of rehospitalization; and (3) to assess the relationship between adherence to and persistence with ACEIs or ARBs, cardiovascular-related health care costs, and total health care costs.
METHODS: Using the prescription and medical service records of a large national pharmacy-benefit database, we conducted a retrospective analysis of patients discharged from the hospital with a primary diagnosis of HF or MI between July 1, 2003, and June 30, 2006. Medication adherence, persistence, rehospitalization risk, and health care costs during 1-year follow-up were measured. Logistic regression models were used to estimate the likelihood of rehospitalization for different levels of adherence and persistence. Generalized linear models were used to investigate the impact of adherence and persistence on total health care costs and cardiovascular-related health care costs.
RESULTS: A total of 799 HF and 696 MI patients were included in the analysis; 57.20% of HF patients and 59.20% of MI patients were prescribed an ACEI or an ARB after discharge from the hospital. The mean (SD) age was 65.7 (13.7) years in the HF group and 60.6 (10.7) years in the MI group. In both groups, men accounted for a greater proportion of the patients than women. In the HF group, adherence and persistence were associated with a lower likelihood of rehospitalization compared with nonadherence and nonpersistence (P < 0.042 and P < 0.005, respectively). In the MI group, there was no significant difference in rehospitalization risk between those who were adherent and those who were not. However, among these patients, persistence was associated with a lower risk of rehospitalization than nonpersistence (P < 0.036). Adherence and persistence were associated with lower health care costs (HF: P < 0.001 for all comparisons; MI: P < 0.019 for adherence and total cost, P = NS for persistence and total cost, P < 0.012 for adherence and cardiovascular cost, P < 0.031 for persistence and cardiovascular cost).
CONCLUSION: Adherence to and persistence with ACEIs or ARBs may reduce the risk of rehospitalization in patients with HF or MI, thereby potentially reducing health care costs.