Beta-blockers may be associated with reduced 1-year mortality rates after hip fracture surgery, according to a retrospective cohort study of 134,915 Swedish adults who underwent primary hip fracture surgery between January 1, 2008 and December 31, 2017.
Investigators identified patients who filled a prescription for beta-blockers within the year before and after surgery. After adjusting for the effects of confounding from nonrandomization, the investigators determined that patients who received beta-blocker therapy both before and after surgery experienced a 42% reduction in mortality risk within the first postoperative year (adjusted HR, 0.58, 95% CI, 0.57 – 0.60; P < .001).
This study, published in the November issue of Anesthesia and Analgesia, comes on the heels of another study by the same authors demonstrating a 90-day mortality reduction following hip fracture surgery if patients received beta-blockers only after surgery.
Shahin Mohseni, MD, PhD, associate professor of surgery at Orebro University Hospital in Sweden and one of the study authors, told Medscape Medical News, “Despite many efforts to decrease the mortality incidence after hip fracture surgery during last decades, the rate of deaths has mainly remained unchanged. Most of these deaths are not due to the surgery per se but the stress caused by the trauma and surgical stress.”
Mohseni pointed out that beta-blockers have been shown to mitigate physiological stress on patients following severe traumatic injuries and other major surgeries. Traumas and surgeries induce a hyperadrenergic state characterized by the activation of the sympathetic nervous system and subsequent release of catecholamines that can increase the strain on the cardiovascular system, resulting in arrhythmias or myocardial infarction.
The investigators theorized that beta-blockers may be protective by inducing a down-regulation of a trauma- and surgery-induced hyperadrenergic state. “So we wanted to investigate if that holds true in this patient population,” he said, referring to hip fracture surgery patients.
The largest reduction in risk was seen with a 76% reduction in cardiovascular mortality (adjusted IRR, 0.24, 95% CI, 0.22 – 0.26; P < .001).
Mohseni thinks it’s important that the beta-blocker protection should occur both before and after surgery, “First for the stress caused by injury preop…and then for the stress caused by surgical trauma postop.”
The investigators also pointed out the differences between their study and another study looking at preoperative beta-blocker use, the Perioperative Ischemic Evaluation (POISE) study. In that study, patients who had not previously been on beta-blockers were randomly assigned to receive extended-release metoprolol 2 to 4 hours before surgery. The patients who received the beta-blocker preoperatively had a lower rate of myocardial infarction but a higher rate of stroke and 30-day mortality.
In their study, Mohseni and co-authors pointed out several differences between the POISE study and their research. For example, in their study, beta-blockers were not given simply because the patient required surgery as in the POISE study. Rather, the patients in the Swedish beta-blocker group were already on the medication before they needed surgery.
Additionally, the POISE study included a spectrum of surgical patients including vascular, orthopedic, and general surgery. In contrast, Mohseni and colleagues focused their study solely on hip fracture surgical patients.
As a result, Mohseni hopes to see a randomized controlled trial of preoperative and postoperative beta-blocker use targeted to hip fracture surgical patients only.
Asked to comment on Mohseni’s study, Karl C. Roberts, MD, program director of the Spectrum Health-Michigan State University Orthopedic Surgery Residency Program in Grand Rapids, told Medscape Medical News, “It does seem like patients with more cardiac risk factors on [beta-blockers (BB)] had lower mortality than a lower risk cohort not on BB. An alternative conclusion could be patients with hypertension, coronary artery disease, or congestive heart failure on beta-blocker therapy had lower mortality rates.
“There is ample evidence in the literature that beta-blocker therapy for appropriate patients perioperatively can decrease cardiac risk,” Roberts continued. “A [randomized controlled trial] looking at intervention in specific patient populations of BB therapy would be required to make any reasonable conclusions about causation, and to answer the real question, which is: Should BB therapy be expanded in hip fracture patients to decrease mortality?”
Mohseni and Roberts have disclosed no relevant financial relationships.
Anesthesia and Analgesia. Published November 2021 issue. Full text
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