Association Between Adherence to Diuretic Therapy and Health Care Utilization in Patients With Heart Failure

Michelle A. Chui, Pharm.D., Ph.D., Melissa Deer, B.S., Susan J. Bennett, D.N.S., Wanzhu Tu, Ph.D., Stacey Oury, B.S., D. Craig Brater, M.D., Michael D. Murray, Pharm.D., M.P.H.


Pharmacotherapy. 2003;23(3) 

In This Article

Abstract and Introduction

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 (µ = 72% ± 30%) and to scheduling (µ = 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 ( 2 11.63, p=0.0006) and predicted more heart failure-related hospitalizations ( 2 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.

Heart failure is a growing health problem, with the number of persons affected increasing steadily. It affects an estimated 4.8 million Americans, and approximately 550,000 new cases are diagnosed each year.[1] Furthermore, in 1997 more than 1 million hospital admissions were attributed primarily to heart failure. The survival of these patients is improved owing to earlier diagnosis, multidisciplinary care, and more effective treatments. Among these treatments are drugs that increase quality of life and reduce morbidity.[2] Despite their availability, however, the success of these agents is incumbent on the patient's willingness and ability to adhere to physicians' prescriptions.

Lack of adherence is often a barrier to successful disease management. Adherence is reported to be 20-82%[3] with an average of 50%.[3,4,5] In one study, only 10% of more than 7000 patients refilled prescriptions for heart failure treatment so they had enough drugs during the entire year of follow-up.[6] Yet adherence and its impact on clinical outcomes have not been fully investigated in this population. It would seem that poor adherence would increase morbidity and mortality, but it is difficult to estimate its scope.

Hospital readmission for heart failure commonly is caused by nonadherence to diuretic therapy or to dietary indiscretions that increase sodium intake.[7,8] Even brief interruptions of several days in diuretic administration could produce fluid overload requiring hospitalization.