Objectives: We previously found large variations in general practitioner (GP) hypertension treatment probability in oldest-old (>80 years) between countries. We wanted to explore whether differences in country-specific cardiovascular disease (CVD) burden and life expectancy could explain the differences. Design: This is a survey study using case-vignettes of oldest-old patients with different comorbidities and blood pressure levels. An ecological multilevel model analysis was performed. Setting: GP respondents from European General Practice Research Network (EGPRN) countries, Brazil and New Zeeland. Subjects: This study included 2543 GPs from 29 countries. Main outcome measures: GP treatment probability to start or not start antihypertensive treatment based on responses to case-vignettes; either low (<50% started treatment) or high (!50% started treatment). CVD burden is defined as ratio of disability-adjusted life years (DALYs) lost