Older patients have increased hypoglycemia risk soon after beta-blocker initiation
Hypoglycemia risk nearly doubled in the immediate period after initiation of beta-blockers compared with long-standing use, and the risk was higher in patients who were also taking insulin, a Canadian study of older patients with type 2 diabetes found.
Older patients with diabetes who initiated beta-blockers were nearly twice as likely to have a hospital encounter for hypoglycemia compared with those prescribed the treatment more than 90 days before the index date, according to results of a population-based study in Canada.
Researchers matched cases of hypoglycemia, defined using ED or hospital admitting diagnosis, with up to 10 controls based on age, sex, diabetes duration, and at least one prescription record for a beta-blocker in the preceding year. Exposure to beta-blockers was classified as new, prevalent, recent, or remote based on the 90- or 30-day period before the event. A total of 26,545 cases and 265,450 matched controls diagnosed with diabetes between April 2003 and March 2019 were included in the study (median age, 78 years; 50% female). All participants lived in Ontario, Canada. Findings were published by the Journal of General Internal Medicine on March 21.
New use of beta-blockers was associated with increased odds of hypoglycemia compared with prevalent use (adjusted odds ratio [aOR], 1.87; 95% CI, 1.75 to 1.99). Neither recent use (aOR, 1.03; 95% CI, 0.98 to 1.08) nor remote use (aOR, 0.82; 95% CI, 0.77 to 0.87) was linked with increased odds of hypoglycemia. The association of hypoglycemia with new use of beta-blockers was greater in patients using insulin during the 90-day exposure window (OR, 2.18; 95% CI, 1.95 to 2.43) versus those not using insulin (OR, 1.73; 95% CI, 1.60 to 1.87) (P<0.01). Nonselective beta-blockers were associated with the greatest increase in risk of hypoglycemia. Researchers also found statistically significant positive associations for cardioselective beta-blockers, atenolol, bisoprolol, and metoprolol, but not for acebutolol.
Limitations to the study include the use of prescription claims as a proxy for beta-blocker exposure and a lack of data on indications for the therapy.
Overall, “we found a near doubling of the odds of hypoglycemia among initiators of beta-blockers compared to prevalent users with the highest risk among persons exposed to nonselective beta-blockers,” the authors wrote. “These findings suggest that the weeks immediately after starting beta-blocker therapy deserve increased vigilance in monitoring for signs and symptoms of hypoglycemia.”