Table 2

Model parameters to inform long-term decision analytic model

Transition probabilitySourcesSpecific details of the fields in source
Remaining in ITNTP
NCRF
Time of withdrawal from IT
Time of withdrawal from IT
LTOT to ITThe trialProportion of people engaged in IT
IT to LTOTNTP
NCRF
Time of withdrawal from IT
Time of withdrawal from IT
IT to SOLMPNTP
NCRF
Time of completely stopping the use of opioids
Time of completely stopping the use of opioids
IT to dead statePLAll-cause mortality data from ONS
Remaining in LTOTThe trialNumber of people who do not engage in IT and remain in LTOT
SOLMP to LTOTPtQ
GPRs
Medication data
Prescription data
LTOT to PTPtQ
GPRs
Medication data
Prescription data
LTOT to dead statePLAll-cause mortality data from ONS
Remaining in PTThe trial
PtQ
GPRs
Number of people who remain in PT over time
Medication data
Prescription data
PT to LTOTPtQ
GPRs
Medication data
Prescription data
PT to SOLMPPtQ
GPRs
Medication data
Prescription data
PT to dead statePLAll-cause mortality data from ONS
Remaining in SOLMPPtQ
GPRs
Medication data
Prescription data
SOLMP to dead stateAll-cause mortality rates from ONS
Utility scoresSourceSpecific details of the source
LTOTPL
PtQ
Utility of opioid therapy45
Regression analysis of patient self-reported EQ-5D
PTPtQRegression analysis of patient self-reported EQ-5D
ITPtQRegression analysis of patient self-reported EQ-5D
SOLMPPtQRegression analysis of patient self-reported EQ-5D
CostsSourceSpecific details of the source
LTOTPL
PtQ
GPRs
Cost of opioid therapy per cycle46
Costs associated with self-reported resource use
Costs associated with resource use collected
PTThe trial
PtQ
GPRs
Cost associated with usual care
Costs associated with self-reported resource use
Costs associated with resource use collected
ITThe trialCost associated with intervention
SOLMPPLAssumption—1× contact with GP28
  • ‘The trial’ means the I-WOTCH trial.

  • GP, general practitioner; GPRs, GP records; IT, I-WOTCH tapering; I-WOTCH, Improving the Well-being of people with Opioid Treated CHronic pain; LTOT, long-term opioid therapy; NCRF, nurse clinical record form; NTP, nurse tapering plan; ONS, Office of National Statistics; PL, published literature; PT, patient-driven tapering; PtD, patient diary; PtQ, patient questionnaire; SOLMP, successful opioid-less management of pain.