Long-term mortality after acute myocardial infarction in relation to prescribed dosages of a beta-blocker at hospital discharge

This study was designed to describe the 5-year mortality rate in relation t o the dose of metoprolol prescribed at hospital discharge after hospitalisa tion for acute myocardial infarction (AMI). All patients discharged alive a fter being hospitalized for AMI at Sahlgrenska Hospital (covering half of t he community of Goteborg, with 500,000 inhabitants) during 1986-1987 (perio d I) and all patients discharged alive after hospitalization for AMI at Sah lgrenska Hospital and Ostra Hospital (covering the whole area of the commun ity of Goteborg) in 1990-1991 (period II) were included. Overall mortality was retrospectively evaluated over 5 years of follow-up. In all there mere 2161 patients who were discharged after AMI. Seventy-three percent of these patients mere prescribed a beta-blocker and 59% were prescribed metoprolol . Of the patients prescribed metoprolol, 34% mere on 200 mg, 46% on 100 mg, and 20% on 50 mg or less. Information on 5-year mortality was available fo r 2142 of the 2161 patients (99.1%). The 5-year mortality was 24% among pat ients prescribed 200 mg, 33% among patients prescribed 100 mg, and 43% amon g patients prescribed 50 mg (P < 0.0001). Patients prescribed another beta- blocker had a 5-year mortality of 39%, and patients prescribed no betablock er at all had a 5-year mortality of 61%. When correcting for dissimilaritie s at baseline, patients who were prescribed <less than or equal to>100 mg h ad an adjusted risk ratio for death of 0.79 (95% confidence limit 0.64-0.96 ; P = 0.021) as compared with patients not prescribed a beta blocker. The c orresponding figure for patients prescribed >100 mg was 0.63 (95% confidenc e limit 0.48-0.84; P = 0.001). Both patients prescribed high and low doses of metoprolol after AMI appeared to benefit from treatment. There was a tre nd indicating more benefit when larger doses were prescribed.