Because it has become practice for some physicians to change therapy from digoxin to an angiotensin-converting enzyme inhibitor and/or diuretic therapy for the management of congestive heart failure,1,2 we included these medications and their use in measuring compliance. Ghali is, of course, right that angiotensin-converting enzyme inhibitors are used in the management of hypertension; faced with the choice of whether to "credit" such use as a therapy for congestive heart failure or not, we opted to err on the conservative side and allow such use to be counted toward compliance. This would have tended to cause our estimate of compliance to appear better than it may have been. Separate analyses that were conducted using only digoxin prescriptions to determine compliance yielded findings quite similar to those reported.
We used the day's supply on each prescription to provide information on the length of therapy. Thus, if the patient were prescribed