Design and rationale of a retrospective clinical effectiveness study of aldosterone antagonist therapy in patients with heart failure.
BACKGROUND
Despite demonstrated efficacy in randomized trials, aldosterone antagonist therapy is not used in many eligible patients with heart failure. Questions remain about its clinical effectiveness and safety for patients who are underrepresented in randomized trials and those at risk for hyperkalemia.


METHODS
The proposed study will evaluate the effectiveness of aldosterone antagonist therapy in eligible Medicare beneficiaries ≥ 65 years old hospitalized for heart failure between 2005 and 2008. Data are from the GWTG-HF registry linked with Medicare inpatient and prescription drug event files. We will use inverse probability-weighted estimators to assess differences in mortality, cardiovascular readmission, and readmission for hyperkalemia between patients who receive or do not receive aldosterone antagonist therapy.


RESULTS
The initial data set included 33,652 patients; 5,463 (16.2%) met all inclusion criteria. Compared with patients who did not meet the inclusion criteria, patients in the final cohort were more likely to be younger (77.3 vs 80.3 years) and male (63.8% vs 41.3%) and to have ischemic heart failure (74.2% vs 59.5%) (all P < .001). Mortality rates were 24.7% at 1 year and 50.7% at 3 years; cardiovascular readmission rates were 50.1% at 1 year and 65.2% at 3 years.


CONCLUSIONS
The proposed study will evaluate the clinical effectiveness of aldosterone antagonist therapy in Medicare beneficiaries hospitalized for heart failure with reduced ejection fraction, an underrepresented population in clinical trials. By addressing this evidence gap, the study has the potential to inform clinical decision making and improve patient outcomes.
Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC 27715, USA. lesley.curtis@duke.edu
Lesley H
LH
Curtis
Xiaojuan
X
Mi
Laura G
LG
Qualls
Bradley G
BG
Hammill
Stephen C
SC
Hammill
Paul A
PA
Heidenreich
Frederick A
FA
Masoudi
Soko
S
Setoguchi
Adrian F
AF
Hernandez
Gregg C
GC
Fonarow
D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000453:epidemiology; D057186:Comparative Effectiveness Research; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D006333:Heart Failure / Q000188:drug therapy* / Q000453:epidemiology; D006801:Humans; D006947:Hyperkalemia / Q000453:epidemiology; D006973:Hypertension / Q000453:epidemiology; D008297:Male; D006278:Medicare; D000451:Mineralocorticoid Receptor Antagonists / Q000627:therapeutic use*; D010359:Patient Readmission / Q000706:statistics & numerical data; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology; D012042:Registries; D012107:Research Design; D014481:United States
D000451:Mineralocorticoid Receptor Antagonists