Page 63 - The efficacy and effectiveness of psychological treatments for eating disorders - Elske van den Berg

Chapter 3 63
bootstrapped samples was extracted from the 50 imputed data sets, with a number of patients per sample equal to the number of patients in the original dataset. For each bootstrapped sample, incremental costs, incremental effects, and incremental cost-effectiveness ratio (ICER) were calculated as: ICER = (CostsCBT-E – CostsTAU)/ (EffectsCBT-E – EffectsTAU), where effect was remission rate based on EDE-Q global score < 2.77. These ICERs were plotted on cost-effectiveness planes and used for further calculations. The reference intervention (TAU) is positioned in the origin of the cost-effectiveness plane where the horizontal axis differences in health gains between CBT-E and TAU indicates, and the vertical axis differences in costs. Along the horizontal and vertical axis, Figure 2 is divided into four quadrants. ICERs in the upper right (“North East”) quadrant indicate that CBT-E generates better health at additional costs, and, in the lower left (“South West”) indicate less health gains from CBT-E at lower costs, compared to TAU. While TAU dominates CBT-E In the upper left (“North West”) quadrant, CBT-E dominates TAU with better health outcomes at lower costs in the lower right (“South East”) quadrant. The scatter plot of ICERs falling within more than one of the quadrants, indicates uncertainty whether the new inter- vention is cost effective compared to TAU. Cost-effectiveness acceptability curves (CEACs) (Van Hout, Al, Gordon, & Rutten, 1994) have been drawn (Figure 2). Based on the distribution of the ICERs, CEACs show the probability that CBT-E is more cost effective than TAU as a function of the willingness to pay (WTP) for one additional recovered eating disorder patient. Costs for one additional recovered eating disorder patient in the Netherlands are, to our knowledge, as yet not established. Crow et al. established a cost-effectiveness ratio for bulimia nervosa patients of 20.317 US dollars (Crow et al., 2013).