1-11 ADVERSE OUTCOMES OF UNDERUSE OF BETA-BLOCKERS IN ELDERLY SURVIVORS OF ACUTE MYOCARDIAL INFARCTION
Beta-blocker prophylaxis after acute myocardial infarction (AMI) is one of the most scientifically substantiated, cost-effective medical services. Their use decreases cardio-vascular mortality and reinfarctions, and increases survival by 20% to 40%. This study asked:

1. What proportion of elderly AMI patients receive prophylactic beta-blockers?
2. Are patient characteristics and use of other drugs (e.g.: calcium-blockers) associated with receipt of beta-blockers?
3. Is non-use associated with increased morbidity and mortality from cardiovascular illness?

Conclusion: Beta-blockers were underused, leading to measurable adverse outcomes.

STUDY

1. Retrospective cohort study (1987-92) of over 3,500 elderly 30-day AMI survivors ( > age 65, all Medicare) who were eligible for beta-blockers. Determined use of beta-blockers in the first 90 days after discharge.
2. Compared mortality rates and hospital re-admissions from cardiovascular causes over 2 years.

RESULTS

1. Only 21% of eligible patients received beta-blocker therapy.
2. Patients were almost 3 times more likely to receive a new prescription for a calcium-blocker than a beta-blocker after their AMI.
3. Advanced age and calcium-blocker use predicted underuse of beta blockers.
4. The adjusted mortality rate among beta-blocker users was substantially less than among non-users in all age groups (65-85).
5. Recipients were re-hospitalized less often than non-recipients.
6. Use of calcium-blockers instead of beta-blockers was associated with double the risk of death, not because they had a demonstrable adverse effect, but because they were substitutes for beta-blockers.

DISCUSSION

1. Substantial opportunities exist for increased use of an inexpensive preventive therapy for reducing morbidity and mortality among elderly AMI patients (even among patients over age 75, an age group that has been consistently excluded from randomized, controlled trials of long-term beta-blocker use).
2. Barriers to use may include: 1) Mistaken belief that beta-blockers are harmful or less beneficial for patients with left ventricular dysfunction or with diabetes (a relative contraindication), and 2) Exaggerated concerns regarding adverse effects on quality of life. (Previous concerns regarding depression, fatigue, and reduced libido have proven to be unsubstantiated if beta-selective agents are prescribed at the lowest effective dose.)
3. In this cohort, patients receiving calcium-blockers alone fared much worse than patients who received beta-blockers alone. (Calcium-blocker recipients had adjusted outcomes similar to patients who received neither calcium-blockers nor beta-blockers.)

CONCLUSION

Despite strong evidence that use of beta-blockers following AMI decreases morbidity and mortality, they are substantially under used in the elderly. Under use leads to excess 2-year mortality and re-hospitalization for cardiovascular disease. Benefits extend to patients over age 75.
JAMA January 8, 1997; 277: 115-121 Original investigation first author from Harvard Medical School. Boston, MA

Comment:

By my calculation from their data, about 10 patients over age 65 need to be treated with beta-blocker (vs non-use) to prevent death of one patient (NNT=10). This is old data (up to 1992). I suspect usage of beta-blockers has improved since, but beta-blockers are still underused. RTJ

[index]