PCSK9 inhibitor safety screening found only two weak signals, both likely confounded

Design

Sequence symmetry analysis of French national health data plus VigiBase disproportionality analysis

Population

36,163 PCSK9 inhibitor initiators and 34,269 matched ezetimibe initiators, 2018 to 2023

Primary outcome

Potential safety signals across about 700 outcomes

Effect

Two signals: inhaled glucocorticoids (adjusted SR 1.19, 1.06 to 1.35) and colony-stimulating factors (2.25, 1.37 to 4.17); none in VigiBase

French researchers combined a sequence symmetry analysis of national health insurance data with a disproportionality analysis in the WHO pharmacovigilance database VigiBase. They compared 36,163 people starting PCSK9 inhibitors between 2018 and 2023 with 34,269 matched ezetimibe starters, to account for temporal trends and indication bias, across about 700 outcomes.

Two potential signals emerged. Initiations of inhaled glucocorticoids were somewhat more likely after PCSK9 inhibitor starts than before (crude sequence ratio 1.25, 95% CI 1.16 to 1.38; ezetimibe-adjusted 1.19, 1.06 to 1.35), as were colony-stimulating factors (crude 4.22, 2.81 to 6.71; adjusted 2.25, 1.37 to 4.17). VigiBase showed no corresponding signal, and the authors attribute both to residual confounding or indication bias.

The analysis is hypothesis-screening. It is reassuring that a broad search found little, but it can only detect events that show up as new prescriptions, and it does not examine long-term outcomes.

• No new safety concern for PCSK9 inhibitors emerged from this broad screening
• Continue to monitor lipids and ask about injection-site reactions as in routine practice
• Do not read the inhaled steroid and colony-stimulating factor findings as drug effects; the authors attribute them to confounding
• Report any unexpected reaction through your national pharmacovigilance system

Why it matters

Prescribers of expensive lipid-lowering injections want to know whether real-world data show surprises, and this one found few.

Don't overread it

Sequence symmetry analysis detects new prescriptions, not diagnoses, and two signals attributed to confounding do not establish harm or safety.

The statistics, in plain English

A sequence ratio compares how often one drug is started after the index drug against before it. Values above 1 suggest a pattern, but the pattern may reflect the illnesses of the people taking the drug rather than the drug itself. Testing 700 outcomes will throw up a few chance results, which is why the authors required both crude and adjusted ratios to exceed 1.

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