Cardiovascular Event Rates After Myocardial Infarction or Ischaemic Stroke in Patients with Additional Risk Factors: A Retrospective Population-Based Cohort Study.

Introduction: The impact of additional risk factors on major cardiovascular event (MACE) rates in patients with a history of myocardial infarction (MI) or ischaemic stroke (IS) treated with statins is not well defined.

Methods: In this retrospective population-based cohort study, patients with a history of MI or IS treated with moderate- or high-intensity statins were identified using Swedish national register data. Patients were incident (index event between July 2006 and December 2014 and followed from diagnosis) or prevalent (MI or IS before July 2006 and followed thereafter). Four subgroups were defined on the basis of additional risk factors associated with increased cardiovascular risk: diabetes mellitus with target organ damage; chronic kidney disease stages 3-4; index event within 2 years after prior MI or IS; and polyvascular disease. First and total MACE rates (i.e. MI, IS, or cardiovascular death) were calculated, and first MACE 10-year risks (prevalent cohort only) were predicted.

Results: Numerically, MACE rates in subgroups were 1.5-3 times higher than in overall populations, and were highest in the 2 years after the index event. First MACE rates in the additional risk factor subgroups were 17.2-33.5 per 100 person-years for the incident cohorts and 9.9-13.2 per 100 person-years for the prevalent cohorts. Total MACE rates per 100 person-years were 20.1-39.8 per 100 person-years and 12.4-17.6 per 100 person-years, respectively.

Conclusion: Despite previous use of moderate- or high-intensity statins, patients with a history of MI or IS, and additional risk factors remain at very high cardiovascular risk.