For elderly patients who had an acute myocardial infarction (MI), initiation of beta-blockers was associated with improved survival but worse functional status, a new study found.
The cohort study included 15,720 patients who lived in a nursing home and had an acute MI between May 1, 2007, and March 31, 2010. Those who took beta-blockers before their MI were excluded, as were those who died or were readmitted within 14 days of hospital discharge. The initial cohort included 8,953 beta-blocker users and 6,767 nonusers (mean age, 83 years), while the propensity-matched cohort included 5,496 users and 5,496 nonusers (mean age, 84 years). Results were published by JAMA Internal Medicine on Dec. 12.
The patients who received beta-blockers were significantly less likely to die in the 90 days after hospitalization (hazard ratio [HR], 0.74; 95% CI, 0.67 to 0.83). The two groups had similar rates of readmission. However, the beta-blocker patients were significantly more likely to experience functional decline during follow-up (odds ratio, 1.14; 95% CI, 1.02 to 1.28). The effect seemed to be driven by patients who were more impaired at baseline—the odds ratios for decline were 1.34 (95% CI, 1.11 to 1.61) in patients with moderate or severe cognitive impairment and 1.32 (95% CI, 1.10 to 1.59) in patients with severe functional dependency. In contrast, beta-blockers were not significantly associated with decline in patients with intact cognition or mild dementia or those in the higher tertiles of functional independence.
Overall, the study found beta-blockers had a number needed to treat of 26 to prevent 1 death among nursing home patients with acute myocardial infarction, the authors found. The number needed to harm with functional decline was 52. But among the patients with greater impairment at baseline, the number needed to harm was 25 to 36, about equivalent to the number needed to treat, the authors noted. The study was limited by its observational design, but because younger and healthier patients are more likely to take beta-blockers, bias would be expected to favor positive outcomes from beta-blockers.
The results show that some elderly patients can benefit from this guideline-directed therapy but that costs and benefits need to be balanced in those with impairments, the authors said. “In this highly vulnerable group, understanding the importance that individual patients place on avoiding death and avoiding functional decline will be critical to guiding decision making about use of these medications,” they concluded.
The study helpfully provides an apparent tipping point of when the costs of beta-blocker therapy may outweigh the benefits for older patients, noted an accompanying comment. It also serves as a reminder for physicians to think about when to discontinue therapy as patients' function declines, the editorialists said.