Background: Noncompliance with long-term medication regimens, such as those employed in the treatment of congestive heart failure (CHF), has been found to be approximately 50%. However, no evaluation has been performed on a population-based cohort of elderly patients beginning the use of digoxin and followed up longitudinally for an extended observation period.
Methods: To study patterns of medication compliance, we conducted a retrospective follow-up of 7247 outpatients aged 65 to 99 years newly prescribed digoxin between 1981 and 1991, with the use of the complete prescription claims file of the New Jersey Medicaid program. Noncompliance was measured in terms of the number of days during the 12-month period after an initial digoxin prescription in which no CHF medication was available to the patient.
Results: Patients started on a regimen of digoxin were without digoxin or any other common alternative CHF drug for an average of 111 of the 365 days of follow-up. Only 10% of the population filled enough prescriptions to have daily CHF medication available for the entire year of follow-up. Compliance rates were higher in patients over 85 years of age, women, those taking multiple medications, and those with hospital or nursing home stays before the initiation of therapy.
Conclusions: A large proportion of patients who begin digoxin therapy end CHF therapy or consume substantially less medication than expected in the first year of therapy. Such high rates of cessation could represent an important impediment to effective CHF therapy.