Time in therapeutic range
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and Keywords: TTR
Overview
Factors Affecting Time in Therapeutic Range (TTR)
Cross trial comparisons of TTR are hampered by variations in:
CHADS Score
A higher CHADS score is associated with a lower TTR. Sicker patients may have reduced access to frequent testing.
Congestive Heart Failure (CHF)
The presence of congestive heart failure Varying drug clearance and distribution (CHF: 63% in ROCKET, 32% RELY, 35% ARISTOTLE)
Country
The TTR is highest in Scandanavian countries (70% to 80%), and lowest in developing countries (40% to 50%)
Comparison of results across trials in TTR are inappropriate unless the TTR in each country should be compared ROCKET AF in those countries who conducted RE-LY and vice versa (adjusting for the number of sites in each country)?
• Should trials only be conducted in countries with a high TTR or should sponsors conduct real world trials throughout the world?