Bisoprolol Lowers Resting Heart Rate and Improves Outcomes in Hypertensive CAD Patients: BISO-CAD Subgroup Analysis
Hypertension (high blood pressure) and coronary artery disease (CAD) are two of the most common—and dangerous—cardiovascular conditions worldwide. Nearly 1 in 3 adults have high blood pressure, and it’s a leading cause of heart attacks, strokes, and heart failure. But here’s a lesser-known risk factor: resting heart rate (RHR). Studies show that a higher RHR (above 70 beats per minute, bpm) is linked to worse outcomes in people with hypertension and CAD—even if their blood pressure is well-managed.
Enter bisoprolol, a beta-blocker often prescribed for hypertension and heart disease. A new subgroup analysis of the multi-national BISO-CAD study reveals that bisoprolol doesn’t just lower RHR—it improves survival and reduces life-threatening cardiac events in people with both CAD and hypertension. Here’s what you need to know.
What Did the Study Do?
This study looked at 681 adults (average age: 65 years, 69% male) with both CAD and hypertension from the larger BISO-CAD trial. BISO-CAD was a phase IV, observational study conducted across China, South Korea, and Vietnam from 2011 to 2015. All patients were already taking bisoprolol (a second-generation beta-blocker) at the start of the study.
Researchers tracked two key things over 18 months:
- Changes in RHR: Measured at baseline, 6, 12, and 18 months (patients rested for 5 minutes before measurements, which were taken for 3 consecutive minutes).
- Composite Cardiac Outcomes (CCCO): A combination of cardiovascular (CV) death, non-fatal heart attack, hospitalization for unstable angina, or the need for revascularization (like a stent or bypass surgery).
The analysis included two groups:
- Intent-to-Treat (ITT): All patients who took at least one dose of bisoprolol.
- Efficacy Analysis (EA): Patients who followed the study protocol fully (no major deviations).
What Did They Find?
The results are clear: bisoprolol effectively lowers RHR—and that matters for survival.
1. Bisoprolol Significantly Reduced Resting Heart Rate
At baseline, the average RHR was ~75 bpm. After 6 months of bisoprolol, it dropped to ~69 bpm—and stayed there for the full 18 months. This reduction was consistent in both the ITT (all patients) and EA (protocol-adherent) groups.
2. Lower RHR = Fewer Life-Threatening Events
Patients with a lower RHR had far fewer cardiac events:
- Those with RHR <65 bpm or <70 bpm had fewer CCCOs than those with RHR ≥65 or ≥75 bpm (in the EA group).
- The biggest red flag? Patients with an average RHR of 70–74 bpm had a 4.34 times higher risk of CCCOs than those with a lower RHR (adjusted odds ratio, 95% CI: 1.19–15.89; P = 0.03).
- Higher RHR (69–74 bpm) also led to more hospitalizations for acute coronary syndrome (ACS) in the ITT group.
3. Blood Pressure Stayed Stable—Benefits Came from RHR, Not BP
Unlike many blood pressure medications, bisoprolol didn’t lower blood pressure in this study. Why? Most patients were already taking other antihypertensive drugs, so their BP was already controlled. The benefits—fewer cardiac events—came exclusively from lower RHR.
4. Low Doses Worked Well (and Were Safe)
Most patients (84%) took bisoprolol at a dose of ≤5 mg/day (44% took 2.5 mg/day, 40% took 5 mg/day). The drug was well-tolerated: only 1.3% of patients had side effects linked to bisoprolol, and serious adverse events were rare (12% total, with 1.5% fatal—most not related to the drug).
Why Does This Matter?
Hypertension and CAD often go hand in hand—and both are driven by an overactive sympathetic nervous system (SNS) (the “fight-or-flight” response). Beta-blockers like bisoprolol work by blocking SNS activity, which lowers RHR and reduces the heart’s workload.
This study adds critical evidence to a growing body of research: controlling RHR is just as important as controlling blood pressure for people with hypertensive CAD. Even if your BP is normal, a high RHR (above 70 bpm) puts you at risk.
Previous studies (like the CLARIFY registry) found that many CAD patients on beta-blockers still had poorly controlled RHR. But bisoprolol stood out: it consistently lowered RHR to a safer range (below 70 bpm) in most patients—even at low doses.
Another key takeaway: you don’t need high doses to see benefits. Most patients in this study got results with 2.5–5 mg/day, which means fewer side effects (a common concern with beta-blockers).
Key Takeaways for Patients and Doctors
If you have both CAD and hypertension:
- Ask about RHR: Even if your blood pressure is controlled, your doctor should check your resting heart rate (aim for <70 bpm, ideally <65 bpm).
- Bisoprolol may be a good option: It’s effective at lowering RHR, improving outcomes, and safe at low doses.
- Stick to your plan: Most benefits came from consistent use over 18 months—don’t stop taking your medication without talking to your doctor.
For doctors:
- Prioritize RHR control: Even in patients with well-managed BP, RHR is a critical risk factor.
- Start low, go slow: Bisoprolol works well at 2.5–5 mg/day for most patients—higher doses aren’t always necessary.
Limitations to Keep in Mind
Like all studies, this one has caveats:
- Observational design: It shows a link between RHR and outcomes, not direct cause.
- Short follow-up: 18 months is useful, but longer studies would show long-term effects.
- Confounding factors: The analysis didn’t include all medications or underlying conditions, which could affect results.
Final Thoughts
This study is a win for people with hypertensive CAD. Bisoprolol— a low-cost, well-tolerated beta-blocker—proves that controlling resting heart rate can make a big difference in survival and quality of life. The message is simple: don’t ignore your resting heart rate—even if your blood pressure is normal.
For more details, read the original study published in the Chinese Medical Journal.
doi.org/10.1097/CM9.0000000000000802
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