α-1 adrenergic receptor antagonists prevent cytokine storm in mouse sepsis models. This led to the hypothesis that α-1 blockers might prevent severe Covid-19, which is characterized by hypercytokinemia and progressive respiratory failure.
We performed an observational case-control study in male Medicare beneficiaries age ≥65 years, with or without benign prostatic hyperplasia (BPH), and treated with α-1 receptor blockers or 5-α reductase inhibitors. Adjusted odds ratios (aOR) and 95% confidence intervals (CI) were estimated for outcomes of uncomplicated and severe Covid-19 hospitalization (intensive care unit admission, invasive mechanical ventilation, or death).
20,963 cases of hospitalized Covid-19 were matched to 101,161 controls on calendar date and neighborhood of residence. In the primary analysis (males with BPH), there was no difference in risk of uncomplicated Covid-19 hospitalization (aOR 1.08, 95% CI 0.996-1.17) or hospitalization with severe complications (aOR 0.97, 95% CI 0.88-1.08). In the secondary analysis (males with or without BPH), the corresponding aORs were 1.02, 95% CI 0.96-1.09 (uncomplicated), and 0.99, 95% CI 0.91-1.07 (complicated), respectively. Subgroup and sensitivity analyses yielded similar results. Of note, there was no difference in risk of severe Covid-19 hospitalization when comparing non-selective vs. selective α-1 blocker use (aOR 0.98, 95% CI 0.86-1.10), higher vs. lower dose α-1 blocker use (aOR 0.96, 95% CI 0.86-1.08), or current vs. remote α-1 blocker use (aOR 1.04, 95% CI 0.91-1.18).
Prevalent use of α-1 receptor blockers was not associated with a protective or harmful effect on risk of uncomplicated or severe hospitalized Covid-19.

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