Efficacy of betablockers in patients with acute coronary syndrome: a systematic review and meta analysis of randomized trials
Bibliographic record
Abstract
Abstract Background Since the inception of clinical guidelines on the management of patients with acute coronary syndrome (ACS), betablocker therapy has been included as a class I recommendation. However, most studies evaluating betablockers in ACS were conducted in the pre-reperfusion era. Currently, the great majority of patients undergo reperfusion and secondary prevention therapy has evolved; the impact of treatment with a betablocker in these patients may be different. Purpose We conducted a systematic review and meta-analysis to evaluate the impact of betablockers on mortality in patients after an ACS in the reperfusion era. Methods We searched MEDLINE, EMBASE, and Cochrane Central Registry of Controlled Trials for RCTs from inception to September 2019. We included randomized controlled trials comparing betablockers to no betablockers in adult patients presenting with an ACS. Independently and in duplicate, we screened titles and abstracts, reviewed the full-text report of potentially eligible studies and extracted data. Two reviewers also evaluated the risk of bias in duplicate. Disagreements were addressed by consensus. We considered trials to be conducted in the reperfusion era if reperfusion was attempted in more than 50% of patients, either with thrombolytics or primary angioplasty. Our primary outcome of interest was all-cause mortality. Secondary outcomes included hospitalization for heart failure, nonfatal myocardial infarction, stroke and cardiogenic shock. We pooled trial outcomes using a fixed effects model. The study protocol is registered with PROSPERO (CRD42019143158). Results After the initial screening of 10,969 references and full-text review of 176 articles, nine RCTs comprising a total of 49,639 patients with ACS were eligible for the final analysis. Predominantly, these patients presented with ST elevation myocardial infarction. Treatment with a betablocker did not improve all-cause mortality at 30 days (risk ratio (RR) 0.98 [95% CI 0.92–1.04], I2=44%), or at longest follow up (up to three years) with RR 0.97 ([95% CI 0.91–1.03], I2=0%). Betablocker therapy was associated with an increased risk of HF hospitalization (RR 1.10 [95% CI 1.05–1.15], I2=52%) and cardiogenic shock during index hospitalization (RR 1.29, [95% CI 1.18–1.40], I2=0%). However, betablocker therapy reduced the risk of nonfatal myocardial infarction (RR 0.72 [95% CI 0.63–0.83], I2=0%); it did not impact the risk of stroke (RR 1.13 [95% CI 0.95–1.35], I2=0%). Conclusion In the reperfusion era, betablocker therapy after an ACS does not appear to improve short or long-term survival. Although betablocker therapy was associated with a reduction in nonfatal myocardial infarction, it increased the risk of heart failure hospitalization and cardiogenic shock. In light of these findings, clinical guidelines should reconsider the strength of their recommendation for betablocker use in the ACS population until further contemporary evidence is available. Funding Acknowledgement Type of funding source: None
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.027 | 0.057 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.028 | 0.037 |
| Bibliometrics | 0.009 | 0.010 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".