Impact of statin therapy on clinical outcomes in chronic heart failure patients according to beta-blocker use: results of CIBIS II

Abstract

Background: HMG-CoA reductase inhibitors (statins) are widely prescribed in patients with established systolic chronic heart failure (CHF). However, there is considerable controversy regarding their benefit in this setting. We therefore conducted a post-hoc analysis of outcomes according to statin use within the Second Cardiac Insufficiency Bisoprolol Study of the beta-blocker, bisoprolol, in NYHA classes III-IV systolic CHF patients (left ventricular ejection fraction <35%), receiving background ACE inhibitor and diuretics.

Methods: Analysis of clinical outcomes was performed according to baseline use of statins and subsequent randomisation to placebo or bisoprolol. Cumulative incidence curves for clinical events were constructed using the Kaplan-Meier method and tested for significance by log-rank statistic. Multivariate analysis was performed using the Cox proportional hazards regression model.

Results: Two hundred and twenty-six of 2,647 patients were receiving statins at baseline (8.5%). Patients were well-matched in the 4 study groups at baseline for gender, weight, NYHA class and LVEF, however statin/bisoprolol patients were significantly younger (p < 0.05). Statin use at baseline was associated with a significant survival benefit compared with no statin use (p < 0.005, hazard ratio [HR] = 0.60, 95% confidence interval [CI] = 0.39-0.94). This benefit remained after adjusting for other significant predictors of survival (p < 0.05, HR = 0.60, 95%CI = 0.39-0.94). A significant interaction effect was noted with bisoprolol, survival being greatest in the statin/bisoprolol group (p < 0.001, HR = 0.14, 95% CI = 0.03-0.60). Survival was 98.3% in the statin/bisoprolol group, 82.1% in the statin/placebo group, 87.2% in the no statin/bisoprolol group and 82.8% in the no statin/placebo group. The statin/bisoprolol group was also associated with fewer cardiovascular (p < 0.005) and sudden deaths (p < 0.0005) compared with other groups.

Conclusions: Despite the post-hoc, non-randomised nature of this analysis, these observations suggest that statin use appears to be beneficial in CHF. Furthermore, there appears to be a favourable interaction between statins and beta-blockade within the Second Cardiac Insufficiency Bisoprolol Study cohort. Prospective studies of statins are required to definitively address the role of these agents in established CHF.