QALYs and incremental net cost per patient over long term in 2015 U.S. dollars. Each observation represents an individual study or results that were reported separately for a particular subgroup in an individual study. Circles, RCT; plus sign, controlled before-after analysis; triangle, uncontrolled before-after analysis. Black, lifetime economic horizon; blue, 40-year economic horizon; orange, 20-year economic horizon.