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 p
erformed on a population-based cohort of elderly patients beginning th
e use of digoxin and followed up longitudinally for an extended observ
ation 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 progr
am. Noncompliance was measured in terms of the number of days during t
he 12-month period after an initial digoxin prescription in which no C
HF medication was available to the patient. Results: Patients started
on a regimen of digoxin were without digoxin or any other common alter
native CHF drug for an average of 111 of the 365 days of follow-up. On
ly 10% of the population filled enough prescriptions to have daily CHF
medication available for the entire year of follow-up. Compliance rat
es were higher in patients over 85 years of age, women, those taking m
ultiple medications, and those with hospital or nursing home stays bef
ore the initiation of therapy. Conclusions: A large proportion of pati
ents who begin digoxin therapy end CHF therapy or consume substantiall
y less medication than expected in the first year of therapy. Such hig
h rates of cessation could represent an important impediment to effect
ive CHF therapy.