Table 1 Model input parameters and probabilistic sensitivity analysis distributions.

From: Cost-effectiveness of a hypothetical cell or gene therapy cure for sickle cell disease

Parameter

Value (95% CI)a

Distribution (parameters)

Source

Yearly discount rate

3 (2.4, 3.6)

Not varied in PSA

Assumption

Number of theoretical patients

10,000

Not varied in DSA or PSA

Assumption

Percent female

51 (41.1, 60.9)

Beta (α = 49, β = 47)

Optum 2007–2017

Initial SCD severities, females

Percent mild

50.8

 

Optum 2007–2017

Percent moderate

22.1

Dirichlet (α1 = 227, α2 = 99, α3 = 121)b

Optum 2007–2017

Percent severe

27.1

 

Optum 2007–2017

Initial SCD severities, males

Percent mild

48.3

 

Optum 2007–2017

Percent moderate

23.1

Dirichlet (α1 = 224, α2 = 107, α3 = 133)b

Optum 2007–2017

Percent severe

28.7

 

Optum 2007–2017

QALY weights, females

Control QALY weight, ages 1–44

0.89 (0.87, 0.91)

Beta (α = 870.42, β = 107.58)

24,25

Control QALY weight, ages 45–54

0.87 (0.85, 0.89)

Beta (α = 983.1, β = 146.9)

24,25

Control QALY weight, ages 55–64

0.84 (0.82, 0.86)

Beta (α = 1128.12, β = 214.88)

24,25

Control QALY weight, ages 65–74

0.84 (0.82, 0.86)

Beta (α = 1128.12, β = 214.88)

24,25

Control QALY weight, ages 75+ 

0.82 (0.8, 0.84)

Beta (α = 1209.5, β = 265.5)

24,25

QALY weights, males

Control QALY weight, ages 1–44

0.89 (0.87, 0.91)

Beta (α = 870.42, β = 107.58)

24,25

Control QALY weight, ages 45–54

0.88 (0.86, 0.9)

Beta (α = 928.4, β = 126.6)

24,25

Control QALY weight, ages 55–64

0.86 (0.84, 0.88)

Beta (α = 1034.58, β = 168.42)

24,25

Control QALY weight, ages 65–74

0.87 (0.85, 0.89)

Beta (α = 983.1, β = 146.9)

24,25

Control QALY weight, ages 75+ 

0.85 (0.83, 0.87)

Beta (α = 1082.9, β = 191.1)

24,25

QALY weights, gender invariant

SCD QALY weight, ages 1–18

0.69 (0.57, 0.80)

Normal (μ = 0.688, σ = 0.058)c

25,26

SCD QALY weight, ages 19+ 

0.68 (0.67, 0.69)

Normal (μ = 0.682, σ = 0.005)c

25,26

Transition probabilities, both genders

Ordered logit transition probability regression coefficients, females

 Moderate SCD (α1)

1.07 (0.64, 1.51)

Normal (μ = 1.074, σ = 0.223)

Optum 2007–2017

 Severe SCD (α2)

2.63 (2.19, 3.06)

Normal (μ = 2.625, σ = 0.22)

Optum 2007–2017

 Age (α3)

− 0.03 (− 0.03, − 0.02)

Normal (μ = − 0.026, σ = 0.004)

Optum 2007–2017

 Moderate SCD * age (α4)

0.01 (0, 0.02)

Normal (μ = 0.007, σ = 0.006)

Optum 2007–2017

 Severe SCD * age (α5)

0.02 (0.01, 0.03)

Normal (μ = 0.021, σ = 0.005)

Optum 2007–2017

 Cut point 1 (κ1)

1.04 (0.76, 1.32)

Normal (μ = 1.04, σ = 0.141)

Optum 2007–2017

 Cut point 2 (κ2)

1.86 (1.57, 2.15)

Normal (μ = 1.858, σ = 0.147)

Optum 2007–2017

Ordered logit transition probability regression coefficients, males

 Moderate SCD (α1)

0.7 (0.23, 1.17)

Normal (μ = 0.701, σ = 0.24)

Optum 2007–2017

 Severe SCD (α2)

1.98 (1.53, 2.42)

Normal (μ = 1.976, σ = 0.225)

Optum 2007–2017

 Age (α3)

− 0.03 (− 0.04, − 0.02)

Normal (μ = − 0.03, σ = 0.004)

Optum 2007–2017

 Moderate SCD * age (α4)

0.01 (0, 0.03)

Normal (μ = 0.012, σ = 0.007)

Optum 2007–2017

 Severe SCD * age (α5)

0.03 (0.02, 0.05)

Normal (μ = 0.034, σ = 0.007)

Optum 2007–2017

 Cut point 1 (κ1)

0.79 (0.49, 1.08)

Normal (μ = 0.787, σ = 0.151)

Optum 2007–2017

 Cut point 2 (κ2)

1.6 (1.3, 1.91)

Normal (μ = 1.605, σ = 0.158)

Optum 2007–2017

Cost parameters

Cost of single administration durable therapy

2.1 M (1.68 M, 2.52 M)

Uniform (a = 1,680,000, b = 2,520,000)

Assumption

GLM gamma log-link cost regression coefficients, females

Intercept (β0)

8.05 (7.88, 8.22)

Normal (μ = 8.051, σ = 0.085)

Optum 2007–2017

Mild SCD (β1)

1.58 (1.3, 1.85)

Normal (μ = 1.575, σ = 0.139)

Optum 2007–2017

Moderate SCD (β2)

1.78 (1.48, 2.09)

Normal (μ = 1.785, σ = 0.154)

Optum 2007–2017

Severe SCD (β3)

3.16 (2.88, 3.45)

Normal (μ = 3.165, σ = 0.147)

Optum 2007–2017

Age (β4)

0.03 (0.03, 0.04)

Normal (μ = 0.032, σ = 0.002)

Optum 2007–2017

Mild SCD * age (β5)

− 0.01 (− 0.02, − 0.01)

Normal (μ = − 0.01, σ = 0.003)

Optum 2007–2017

Moderate SCD * age (β6)

− 0.01 (− 0.02, − 0.01)

Normal (μ = − 0.014, σ = 0.003)

Optum 2007–2017

Severe SCD * age (β7)

− 0.02 (− 0.03, − 0.02)

Normal (μ = − 0.023, σ = 0.003)

Optum 2007–2017

GLM gamma log-link cost regression coefficients, males

Intercept (β0)

8.39 (7.51, 9.28)

Normal (μ = 8.395, σ = 0.452)

Optum 2007–2017

Mild SCD (β1)

2.13 (1.16, 3.09)

Normal (μ = 2.126, σ = 0.494)

Optum 2007–2017

Moderate SCD (β2)

1.14 (0.21, 2.07)

Normal (μ = 1.14, σ = 0.475)

Optum 2007–2017

Severe SCD (β3)

2.36 (1.46, 3.27)

Normal (μ = 2.364, σ = 0.46)

Optum 2007–2017

Age (β4)

0.02 (0.01, 0.04)

Normal (μ = 0.024, σ = 0.009)

Optum 2007–2017

Mild SCD * age (β5)

− 0.02 (− 0.03, 0)

Normal (μ = − 0.016, σ = 0.009)

Optum 2007–2017

Moderate SCD * age (β6)

0.01 (− 0.02, 0.03)

Normal (μ = 0.006, σ = 0.011)

Optum 2007–2017

Severe SCD * age (β7)

− 0.01 (− 0.02, 0.01)

Normal (μ = − 0.005, σ = 0.009)

Optum 2007–2017

  1. PSA probabilistic sensitivity analysis, DSA deterministic sensitivity analysis, GLM generalized linear model.
  2. aConfidence intervals omitted for variables drawn from multivariate distributions.
  3. bNot varied in DSA.
  4. cTruncated normal distribution on [0,1].
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