Table 2 Model input parameters

1. Relative risk of death in patients with RA who had high disease activity

2.43 (1.22)

Lognormal

[3]

2. Probability of adverse events^c

0.0008 (0.00003)

Beta

^a

3. Survival analysis

 3.1 Transition from high to moderate / low disease activity

  Constant in survival analysis for baseline hazard

1.55

Lognormal

Medical record review

  Disease duration coefficient in survival analysis for baseline hazard

-0.08

Lognormal

  Lambda parameter survival analysis (depends on chosen coefficients)

1.61

Lognormal

  Ancillary (shape) parameter in the Weibull distribution

1.08

Lognormal

  Mean disease duration of RA patients from 3 hospitals

14

Lognormal

 3.2 Transition from high disease activity to remission

  Constant in survival analysis for baseline hazard

-2.92

Lognormal

Medical record review

  Lambda parameter survival analysis (depends on chosen coefficients)

0.05

Lognormal

  Ancillary (shape) parameter in the Weibull distribution

1.00

Lognormal

 3.3 Transition from moderate / low to high disease activity

  Constant in survival analysis for baseline hazard

-1.39

Lognormal

Medical record review

  Lambda parameter survival analysis (depends on chosen coefficients)

0.25

Lognormal

  Ancilliary (shape) parameter in Weibull distribution

0.50

Lognormal

 3.4 Transition from moderate / low disease activity to remission

  Constant in survival analysis for baseline hazard

-1.86

Lognormal

Medical record review

  Lambda parameter survival analysis (depends on chosen coefficients)

0.16

Lognormal

  Ancillary (shape) parameter in the Weibull distribution

0.63

Lognormal

 3.5 Transition from remission to moderate / low disease activity

  Constant in survival analysis for baseline hazard

-0.22

Lognormal

Medical record review

  Lambda parameter survival analysis (depends on chosen coefficients)

0.80

Lognormal

  Ancillary (shape) parameter in the Weibull distribution

0.96

Lognormal

4. Costs (adjusted to 2022 value)

 4.1 Direct medical costs (THB)

  OPD service (per visit)

78

-

[19]

  IV infusion (per visit)

31

-

  Treatment for serious adverse events (per admission)^c

36070 (1274)

Gamma

^a

  Drug costs (THB per 6 months)

  Standard of care + MTX

18700

-

Reference drug price from DMSIC

  Etanercept + MTX

108500

-

^b

  Infliximab + MTX

168700

-

^b

  Golimumab + MTX

217400

-

^b

  Tocilizumab + MTX

102400

-

^b

  Rituximab + MTX

98000

-

^b

  Tofacitinib + MTX

89000

-

^b

  Baricitinib + MTX

89200

-

^b

  Biosimilar infliximab (Remsima®) + MTX

101500

-

^b

  Biosimilar infliximab (Ixifi®) + MTX

68000

-

^b

  Biosimilar adalimumab (Amgivita®) + MTX

90300

-

^b

  Biosimilar rituximab (Truxima®) + MTX

78600

-

^b

  Lab costs before starting treatment (THB at the first visit for every regimen)

  X-ray (Hand)

265.04

-

[19]

  X-ray (Foot)

531.25

-

  X-ray (Chest)

265.04

-

  Complete blood count (CBC)

140.05

-

  Erythrocyte sedimentation rate (ESR)

62.50

-

  Test for TB (modified AFB)

108.80

-

  Liver function test (LFT)

546.29

-

  Serum creatinine (SCr)

77.55

-

  Lipid profile

312.50

-

 4.2 Direct non-medical cost (THB per visit)

  Transportation fare

329.97

-

[19]

  Food

121.55

-

5. Number of OPD visits (time per 6 months)

 High disease activity

6

-

[5]

 Moderate / Low disease activity

2

-

 Remission

1

-

6. Utilities

 High disease activity

0.79 (0.05)

Beta

[20]

 Moderate / Low disease activity

0.86 (0.01)

Beta

 Remission

0.93 (0.01)

Beta