The absolute benefit from antihypertensive therapy increases with the baseline risk. However, age is a major determinant of cardiovascular risk, so it is important to express therapeutic efficacy with indices for which age is not a confounder. With this aim we explored the expected gain in life expectancy without cardiovascular events according to age at the initiation of the treatment. The treatment effect estimated from the INDANA meta-analysis, was applied to the cardiovascular risk of a French hypertensive population, simulated from national vital statistics. The gain in life expectancy was estimated from the area between survival curves without events. The treatment effect varied according three different hypotheses: increasing, decreasing or constant effect. When assuming a constant treatment effect, our results show a 29 month gain without stroke for a man who began his treatment at 40 years, and 15 months if hypertension is screened and treatment initiated at 75 years. The gains without coronary heart disease are respectively of 11 and 6 months. The variation of treatment effect over time could have a major impact on the treatment benefit. The gain in life expectancy without events is a relevant decision tool, completing usefully the absolute benefit, since it takes into account the influence of age.