HF incidence on aspirin: 14.5/1000 person-years
Overall, the incidence rate of HF per 1,000 person-years for the entire population before adjustment was 14.5 in the group on daily aspirin versus 5.9 in the non-aspirin group. These absolute rates were lower in the discovery data set than in the validation set, but the relative differences in HF incidence rates for those who were versus those who were not on aspirin at baseline were similar.
Numerous sensitivity analyses supported the basic conclusions. This not only included one omitting patients with a history of CVD, but another that excluded patients who developed HF within the first 2 years. Stratified analyses looking for overall consistency across variables showed increased risk of new onset heart failure among those taking daily aspirin regardless of relative age, body weight, or blood pressure levels.
The most important limitation of this study was that it evaluated data taken from studies not originally designed to test the study hypothesis. In addition, only baseline data were available, so the drugs that patients took over the course of follow-up are unknown. However, the authors believe these data have a clinical message.
Given the consistency of these results, “our observations suggest that aspirin should be prescribed with caution in patients at risk of HF or having HF,” the investigators concluded.
“If such treatment is initiated in these patients, use low-dose aspirin,” Dr. Staessen told this news organization.
Aspirin for CVD versus HF risk
Many patients take low-dose aspirin to prevent the types of cardiovascular events, such as MI, that lead to heart failure. In attempting to address a controversy regarding aspirin and risk of new onset heart failure, it appears to create another regarding CVD risk reduction.
Deepak L. Bhatt, MD, executive director of Interventional Cardiovascular Programs at Brigham and Women’s Health, Boston, expressed some reluctance in applying these data to routine practice.
“It is important to emphasize that this pooled analysis draws upon six observational studies, not randomized trials of aspirin,” Dr. Bhatt said.
He called these findings “provocative,” but he said they “would need to be confirmed in databases of already completed randomized trials of aspirin versus a control before being actionable.” For Dr. Bhatt, one obstacle to a change in practice based on these data is that, “to my knowledge, no such signal [of a relationship between aspirin and incident heart failure] exists in the cumulative randomized data.”
Dr. Staessen reports no potential conflicts of interest for this study. Dr. Bhatt has a financial relationship with a large number of pharmaceutical companies, including PLx Pharma, for which he performs aspirin-related research.