Long-term continuation on cardiovascular drug treatment in patients with coronary heart disease.

BACKGROUND: Combination therapy to reduce risk factors is effective in preventing recurrent cardiovascular disease events in patients with coronary heart disease (CHD), but medications need to be continued indefinitely to maximize the benefits. OBJECTIVE: To evaluate the extent of long-term continuation with cardiovascular drug therapy and its expected impact on the prevention of CHD. METHODS: We studied 242 patients with CHD who underwent percutaneous coronary intervention following an acute coronary syndrome over a 6 month period in 2004. We prospectively examined the extent to which specific drugs and drug combinations were continued over time by reviewing medication use at the time of hospital discharge and after 2 years. The results were used to estimate the expected loss in preventive efficacy due to discontinuation of therapy. RESULTS: The changes over a 2 year period in the proportions of patients taking each drug class were as follows: 15% reduction for aspirin (95% CI, -21 to -9), 10% reduction for statins (95% CI, -16 to -5), 19% reduction for angiotensin-converting enzyme inhibitors (95% CI, -26 to -12), 12% reduction for beta-blockers (95% CI, -18 to -6), 0% increase for calcium-channel blockers (95% CI, -5 to 6), 2% increase for thiazides (95% CI, -2 to 6), and 12% increase for angiotensin-II receptor blockers (95% CI, 6 to 18). The combination of aspirin, statin, and at least 2 blood pressure lowering drugs was prescribed to 81% of patients, three-quarters of whom remained on this combination after 2 years. The overall expected preventive effect on CHD of the combined medication taken during hospitalization and after 2 years was 80% and 74%, respectively. CONCLUSIONS: In patients with CHD, long-term continuation of combination cardiovascular drug therapy is considerably greater than generally perceived.