Govert Veldhuijzen

122 Chapter 6 Statistics Presentation of the data will include the means, medians, standard deviations and ranges for quantitative data. In case of categorical data, counts and frequencies are used. For estimating the mean and 95% CI for endoscopy unit and productivity loss costs in the CBE group, we performed bootstrapping after data imputation. RESULTS Endoscopy unit operational costs On the basis of our original trial we calculated that 209 patients received CBE alone (74.6%) versus 71 patients receiving CBE with additional action (25.4%). 20 Stratification on trial site level explains the small difference with the patient reported data (CBE alone 78.5%, CBE with additional action 21.5%). The adaptation of the cost model after process evaluation resulted in 33 relevant parameters for cost calculation. Input for all parameters was retrieved from the four trial units. (See supplementary materials tables 1s. and 2s.) This resulted in varying costs per trial for the three patient routes per trial site: nurse counselling €18.30 - €28,42, CBE alone €4,04 - €8.86 and CBE with additional counselling €7,01 - €19,78. (Table 1.) Table 1. Average costs for patient education routes per trial site 1. Urban Costs in euro (n, %) 2. Academic Costs in euro (n, %) 3. Urban Costs in euro (n, %) 4. Rural Costs in euro (n, %) Nurse counselling (n = 217) € 19,20 (67, 38.5%) € 28,42 (72, 42.6%) € 21,46 (43, 48.3%) € 18,30 (35, 51.5%) CBE alone (n = 209) € 5,05 (89, 51.1%) € 8,86 (66, 39.1%) € 5,88 (23, 25.8%) € 4,04 (31, 45.6%) CBE with additional counselling (n = 71) € 9,25 (15, 8.6%) € 19,78 (31, 18.3%) € 12,18 (23, 25.8%) € 7,01 (2, 2.9%) Total, n (% of 497 patients) 171 (34.4 %) 169 (34.0 %) 89 (17.9 %) 68 (13.7 %) The academic trial site noted the highest costs to educate patients. The rural based trial site had the lowest cost per patient. Main drivers of the differences in costs between trial sites were time spend by staff and the staff wages (see supplementary materials). The pay rate variation amongst trial sites was explained by the average age and level of experience of staff members. The calculated costs per trial site were used to perform total cost minimization calculation: this allowed comparison of average cost of the CBE versus average cost of nurse counselling for all 497 patients.