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Table 2 Parameters used in the model

From: Cost-utility analysis of adjuvant imatinib treatment in patients with high risk of recurrence after gastrointestinal stromal tumour (GIST) resection in Thailand

Parameters Distribution Mean SE References
Probability of recurrence in patients with no adjuvant imatinib treatment (per month)
 Probability of recurrence at year 1 Beta 0.0205 0.0041 Chart reviewa
 Probability of recurrence at year 3 Beta 0.0154 0.0031
 Probability of recurrence at year 5 Beta 0.0056 0.0011
Probability of death from GIST in patients with no adjuvant imatinib treatment (per month)
 Probability of death at year 1 Beta 0.0017 0.0003 Chart reviewa
 Probability of death at year 3 Beta 0.0031 0.0006
 Probability of death at year 5 Beta 0.0028 0.0006
 Probability of death at year 7 Beta 0.0020 0.0004
 Probability of death at year 9 Beta 0.0038 0.0008
Hazard ratio (HR) of recurrence in patients receiving adjuvant imatinib treatment (compared with no adjuvant imatinib treatment)
 Adjuvant imatinib treatment for 1 year Log normal 0.29 0.0995 [6]b
 Adjuvant imatinib treatment for 3 years Log normal 0.133 0.0543 Indirect comparison of [6] and [7]
Probability of progression during treatment (per month)
 Imatinib treatment Beta 0.015 0.0038 [12]
 Sunitinib treatment Beta 0.012 0.0010
Probability of death during treatment (per month)
 Imatinib treatment Beta 0.0056 0.0009 [12]
 Sunitinib treatment Beta 0.0289 0.0087
 Best supportive care Beta 0.0680 0.0093
Probability of discontinuation of adjuvant imatinib treatment (per month)
 Adjuvant imatinib treatment for 1 year (1–6 months) Beta 0.0136 0.0014 [17]
 Adjuvant imatinib treatment for 1 year (7–12 months) Beta 0.0009 0.0001
 Adjuvant imatinib treatment for 3 years (1–6 months) Beta 0.0097 0.0001
 Adjuvant imatinib treatment for 3 years (7 months onwards) Beta 0.0028 0.0003
Direct medical costs (THB per month)
 Imatinib 400 mg/day 111,306 [14]
 Sunitinib 50 mg/day (receive drug for 4 weeks, then stop for 2 weeks, and repeat a cycle) 82,173
 Costs for patients with no recurrence and no adjuvant imatinib treatment Gamma 2758 308 Hospital database
 Costs for patients with no recurrence and receiving adjuvant imatinib treatmentc Gamma 1477 573
 Costs for patients during recurrence and receiving imatinib treatmentc Gamma 421 38 [12]
 Costs for patients during recurrence and receiving sunitinib treatmentc Gamma 714 150
 Costs for patients during recurrence and receiving best supportive care Gamma 424 78
 Costs for treating adverse events from adjuvant imatinib treatment Gamma 570 114 Expert opinion
Direct non-medical costs
 Travel costs (THB per visit) Gamma 296 24 [15]
 Food costs (THB per visit) Gamma 109 11
 Opportunity cost of caregivers (THB per visit) Gamma 99 37
 Number of visits for patients with no recurrence and no adjuvant imatinib treatment (visits per month) Gamma 0.3 0.1 Hospital database
 Number of visits for patients with no recurrence and receiving adjuvant imatinib treatment (visits per month) Gamma 0.6 0.2
 Number of visits for patients during recurrence (visits per month) 1 [12]
Utility
 No recurrence and no adjuvant imatinib treatment Beta 0.89 0.03 Interviewing patients
 No recurrence and receiving adjuvant imatinib treatment Beta 0.79 0.09
 Recurrence and receiving imatinib treatment Beta 0.66 0.05 [12]
 Recurrence and receiving sunitinib treatment Beta 0.58 0.06
 Recurrence and receiving best supportive care Beta 0.42 0.03
  1. a Sarunporn Techasurungkul, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, personal communication, November 20, 2014
  2. b The study population was patients with GIST of greater than 3 cm, so only a subgroup analysis of patients with GIST of greater than 10 cm was used to represent patients with high risk of recurrence
  3. cExcluding drug costs (imatinib or sunitinib)