Impact of Geographic Region on the COMMANDER-HF Trial.

Objectives: This study sought to compare patient characteristics, outcomes, and treatment effects among regions in the COMMANDER-HF trial.

Background: Globalization of cardiovascular trials increases generalizability. However, regional differences may also introduce heterogeneity in results.

Methods: Incidence rates and interactions with treatment were recorded in pre-specified regions: Eastern Europe, Western Europe and South Africa, North America, Asia-Pacific, and Latin America.

Results: Most patients (n = 3,224; 64.2%) were from Eastern Europe; 458 (9.1%) were from Western Europe and South Africa; 149 (3.0%) were from North America; 733 (14.6%) were from Asia-Pacific; and 458 (9.1%) were from Latin America. Compared with patients from Eastern Europe, patients from Western Europe and South Africa, North America, and Asia-Pacific were older and more likely to have coronary interventions and cardiac devices. Patients from Eastern Europe had the lowest event rates. For the primary outcome of myocardial infarction (MI), stroke, or all-cause death, event rates (100/year) were 11.6 in Eastern Europe (10.8 to 12.5); 19.5 (16.5 to 23.0) in Western Europe and South Africa; 14.2 (10.5 to 19.2) in North America; 17.7 (15.4 to 20.3) in Asia-Pacific; and 18.6 (15.6 to 22.1) in Latin America. There was a lower incidence of bleeding in Eastern Europe. Blood concentrations of rivaroxaban (Xarelto, Titusville, New Jersey) at 4 weeks were undetectable in 21% patients from Eastern Europe (n = 128) compared to 5% in other regions (n = 42). There was no evidence of treatment-by-region heterogeneity for the primary outcome (interaction = 0.14), but a favorable effect on the secondary outcome of MI, stroke, or cardiovascular death was observed in Western Europe and South Africa, North America, and Latin America but not in Eastern Europe and Asia-Pacific (interaction = 0.017).

Conclusions: In the COMMANDER-HF study, patients from Eastern Europe had a lower risk profile and fewer cardiovascular and bleeding events, possibly related to lower treatment adherence. Those differences might have influenced the effect of rivaroxaban therapy. (A Study to Assess the Effectiveness and Safety of Rivaroxaban in Reducing the Risk of Death, Myocardial Infarction or Stroke in Participants With Heart Failure and Coronary Artery Disease Following an Episode of Decompensated Heart Failure [COMMANDER HF]; NCT01877915).