Association between adherence to diuretic therapy and health care utilization in patients with heart failure.

STUDY OBJECTIVE: To determine the relationship between adherence to diuretic therapy and health care utilization. DESIGN: Prospective, observational study. SETTING: University-affiliated medical center. PATIENTS: Forty-two patients with heart failure. INTERVENTION: Electronic monitoring of adherence to diuretic therapy (percentage of diuretic prescription container openings) and to scheduling (percentage of container openings within a specific time). MEASUREMENTS AND MAIN RESULTS: All patients were prescribed a diuretic, most commonly furosemide (88%). Patients varied widely in adherence to therapy (mu = 72% +/- 30%) and to scheduling (mu = 43% +/- 30%). Education was a predictor of drug-taking adherence (p=0.0062) but not of scheduling adherence. Log-linear models revealed that poor scheduling adherence was associated with increased cardiovascular-related hospitalizations (chi2 11.63, p=0.0006) and predicted more heart failure-related hospitalizations (chi2 4.04, p=0.0444). In contrast, neither measure was significantly associated with cardiovascular- or heart failure-related emergency department visits. We found a moderate correlation between scheduling adherence and taking adherence (r = 0.6513). CONCLUSION: Patients taking a greater proportion of diuretic agents on schedule may decrease the risk of cardiovascular- and heart failure-related hospitalizations. If these findings are confirmed by a larger study, interventions to improve adherence and patient health outcomes should consider the timing of doses as well as the number of daily doses of a diuretic.