Clinical Effectiveness of Hydralazine–Isosorbide Dinitrate Therapy in Patients With Heart Failure and Reduced Ejection Fraction: Findings From the Get With The Guidelines-Heart Failure Registry

Background—In clinical trials, hydralazine–isosorbide dinitrate (H-ISDN) for heart failure with reduced ejection fraction reduced morbidity and mortality among black patients and patients with intolerance to angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers. The effectiveness of H-ISDN in clinical practice is unknown. Methods and Results—Using data from a clinical registry linked with Medicare claims, we examined the use and outcomes of H-ISDN between 2005 and 2011 among older patients hospitalized with heart failure and reduced ejection fraction. We adjusted for demographic and clinical characteristics using Cox proportional hazards models and inverse probability weighting. Among 4663 eligible patients, 22.7% of black patients and 18.2% of patients not on an angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker were newly prescribed H-ISDN therapy at discharge. By 3 years, the cumulative incidence rates of mortality and readmission were similar between treated and untreated patients. After multivariable adjustment, 3-year outcomes remained similar for mortality [black patients: hazard ratio (HR), 0.92; 95% confidence interval (CI), 0.75–1.13; other patients: HR, 0.93; 95% CI, 0.79–1.09], all-cause readmission (black patients: HR, 0.98; 95% CI, 0.84–1.13; other patients: HR, 1.02; 95% CI, 0.90–1.17), and cardiovascular readmission (black patients: HR, 0.99; 95% CI, 0.82–1.19; other patients: HR, 0.94; 95% CI, 0.81–1.09). A post hoc analysis of Medicare Part D data revealed low postdischarge adherence to therapy. Conclusions—Guideline-recommended initiation of H-ISDN therapy at hospital discharge was uncommon, and adherence was low. For both black patients and patients of other races, there were no differences in outcomes between those treated and untreated at discharge.