Beta-blockers and inhibitors of the renin-angiotensin aldosterone system for chronic heart failure with preserved ejection fraction (Cochrane review 6/2018)
We have long treated heart failure with a preserved ejection fraction (HFpEF) as we treat patients with reduced ejection fractions (HFrEF). This approach is extrapolated from studies demonstrating mortality benefits in patients using beta-blockers, ACE-I/ARB’s, and mineralocorticoid receptor antagonists. The benefit of these therapies is in part due to blockade of the neurohumoral remodeling of the heart that results through increased catecholamines and activation of the renin-angiotensin-aldosterone system as highlighted in this NEJM review. HFpEF carries a prognosis similar to that of HFrEF, yet HFpEF patients are often not included in current studies. The authors of this recently published Cochrane review explored the effect of beta-blockers and ACE-I/ARB’s as well as mineralocorticoid receptor antagonists (MRA: spironolactone, eplerenone) in patients with heart failure with preserved ejection fraction. The authors found that there was low quality evidence supporting the use of beta blockers in HFpEF to reduce mortality (RR 0.78, 95% CI: 0.62-0.99). MRA’s were associated with decreased hospitalizations, but no difference in mortality and an increased risk of hyperkalemia (RR 2.11, 95% CI: 1.77-2.51). ACE/ARB therapy did not have a substantial impact on overall mortality, though ARB’s did have an increased risk of hyperkalemia
Take Home: Beta-blockade appears to provide a small reduction in cardiovascular mortality, but not overall mortality in patients with HFpEF, however the quality of evidence supporting this is low. Currently, ACE-I/ARB and MRA therapy do not appear to have a significant effect on mortality based on available evidence.
Probiotics to Prevent Clostridium Difficile Infection in Patients Receiving Antibiotics (JAMA 7/2018)
Infection with Clostridium Difficile is common amongst the hospitalized patient population due to antibiotic use. Previous studies have reported rates of C. Diff identification as high as 30% amongst hospitalized patients. Probiotics have had an unclear role in the prevention of both C. Difficile infection (CDI) in patients receiving antibiotic therapy, and in the prevention of antibiotic associated diarrhea. This JAMA Clinical Evidence Synopsis explored the role of prophylactic probiotics in patients receiving antibiotic therapy. The authors found that administration of probiotics with antibiotics was associated with a decreased risk for CDI (RR 0.4, 95%CI: 0.3-0.52). However, when subgroup analysis was performed, only patients with a CDI risk of > 5% demonstrated a decreased risk of CDI with probiotic use (RR: 0.3, 95% CI: 0.21-0.42). Interestingly, the authors noted that there was no difference in rate of C. Diff detection in the stool of patients tested, suggesting that probiotics may not prevent colonization but instead reduce risk of symptomatic infection. Probiotics were also associated with lower rates of abdominal cramping and nausea based on very low-quality evidence.
Take Home: Probiotics help reduce the incidence of Clostridium difficile infection in patients at high risk. Probiotics may also decrease the risk in patients at moderate risk for C. diff infection. Probiotics appear to be associated with lower rates of abdominal cramping and nausea based on low quality evidence.