Background: Although ?-blockers (BB) theoretically increase the risk of severe or prolonged hypoglycemia, studies have suggested that BB may decrease the risk of hypoglycemia-associated arrhythmias and death. However, there is little evidence in hospitalized patients on insulin.

Aim: To determine the relationship between BB use and incidence of hypoglycemia and mortality in hospitalized patients.

Methods: We retrospectively identified non-critically ill hospitalized patients receiving subcutaneous insulin and undergoing bedside glucose monitoring over a 2 year period. BB and basal insulin use were identified on the admission medication list. Hypoglycemia, defined as any glucose < 70 mg/dl within 24 hours of admission (Hypo24) or throughout the hospitalization (HypoT) and any glucose <40 mg/dl throughout the hospitalization (Hypo40) were compared between patients with and without BB.

Results: 13,424 patients were included, with 2648 patients receiving a BB at admission (19.7%). After controlling for other variables, the odds of Hypo24 HypoT and Hypo40 were higher for BB recipients (Hypo24 OR 3.79, 95% CI 3.21-4.50, p<0.0001, fully adjusted model; HypoT OR 7.70, 95% CI 6.77-8.77, p<0.0001, fully adjusted model; Hypo40 OR 1.95, 95% CI 1.49-2.57, p<0.0001). However, there was a significant interaction across basal insulin usage, with increased odds of HypoT and Hypo40 among basal insulin non-users but not basal insulin users. Hypo24, HypoT, and Hypo40 were associated with increased mortality in adjusted models. There was evidence of an interaction by BB status in the relationship between Hypo24 and mortality (with increased mortality among non-users but not users), but not at other time points.

Conclusions: BB use is associated with higher risk of hypoglycemia in hospitalized basal insulin non-users, but not basal insulin users. Hypoglycemia is associated with increased hospital mortality, regardless of BB use, but early hypoglycemia-associated mortality risk is attenuated by BB use.


J. Merrill: None. K.M. Dungan: Research Support; Self; Novo Nordisk Inc.. Advisory Panel; Self; Sanofi-Aventis. Research Support; Self; Sanofi-Aventis, GlaxoSmithKline plc.. Consultant; Self; GlaxoSmithKline plc.. Research Support; Self; AstraZeneca. Other Relationship; Self; DKBmed, Horizon, Projects in knowledge, Rockpointe.

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