Skip to main content

Table 2 Resultsa of the simulation study on the main parametersb

From: When a joint model should be preferred over a linear mixed model for analysis of longitudinal health-related quality of life data in cancer clinical trials

  

LMM

JM

True

Mean

Bias

RB

RMSE

Cov.

Mean

Bias

RB

RMSE

Cov.

SCENARIO 0

HRQoL

β1

0.3

0.603

0.303

1.010

0.371

70.8

0.297

− 0.003

− 0.011

0.22

95.7

β2

1.2

1.141

−0.059

− 0.049

0.287

93.1

1.215

0.015

0.012

0.284

93.3

β1 + β2

1.5

1.744

0.244

0.163

1.512

0.012

0.008

Risk of dropout

γ1

− 0.4

− 0.403

− 0.003

0.007

0.103

93.8

α

−0.02

− 0.02

0

0.003

0.003

95.2

SCENARIO 1

HRQoL

β1

0

−0.007

−0.007

NA

0.183

94.1

−0.008

−0.008

NA

0.184

94.2

β2

1.5

1.508

0.008

0.005

0.253

93.4

1.508

0.008

0.005

0.253

93.3

β1 + β2

1.5

1.501

0.001

0.001

1.5

0

0

Risk of dropout

γ1

0

−0.002

−0.002

NA

0.102

93.4

α

0

0

0

NA

0.002

94.9

SCENARIO 2

HRQoL

β1

0

0.356

0.356

NA

0.404

52.7

0.004

0.004

NA

0.198

94.3

β2

1.5

1.465

−0.035

−0.023

0.255

93.1

1.517

0.017

0.011

0.260

93.4

β1 + β2

1.5

1.821

0.321

0.214

1.521

0.021

0.014

Risk of dropout

γ1

0

−0.003

− 0.003

NA

0.110

94.3

α

−0.03

−0.03

0

0

0.003

95.5

SCENARIO 3

HRQoL

β1

0

0.343

0.343

NA

0.391

53.0

−0.003

−0.003

NA

0.193

94.2

β2

1.5

1.359

−0.141

− 0.094

0.274

88.6

1.515

0.015

0.01

0.240

93.0

β1 + β2

1.5

1.702

0.202

0.135

1.512

0.012

0.008

Risk of dropout

γ1

−0.7

− 0.704

−0.004

0.006

0.115

94.4

α

−0.03

−0.03

0

0.001

0.003

95.4

SCENARIO 4

HRQoL

β1

0

0.352

0.352

NA

0.397

51.8

0.002

0.002

NA

0.190

95.2

β2

0

−0.098

−0.098

NA

0.255

91.7

0.014

0.014

NA

0.241

93.8

β1 + β2

0

0.254

0.254

NA

0.016

0.016

NA

Risk of dropout

γ1

−0.7

− 0.706

−0.006

0.009

0.108

94.1

α

−0.03

−0.030

0.000

0.002

0.003

94.8

SCENARIO 5

HRQoL

β1

0

0.342

0.342

NA

0.39

54.2

−0.009

−0.009

NA

0.194

94.8

β2

−1.5

−1.551

−0.051

0.034

0.245

93.9

−1.482

0.018

−0.012

0.245

94.4

β1 + β2

−1.5

−1.209

0.291

0.582

−1.491

0.009

−0.006

Risk of dropout

γ1

−0.7

−0.7

0

0

0.115

93.9

α

−0.03

−0.03

0

−0.003

0.003

94.5

  1. amean, bias, relative bias (RB), root mean square error (RMSE) and coverage rate (Cov.) based on 1000 generated datasets of 500 patients
  2. b β1 and β2: time and interaction parameters characterizing the slope of the HRQoL trajectory in the control and experimental arms; γ1 and α: effects of treatment and HRQoL on risk of dropout
  3. HRQoL, Health-related quality of life; JM, Joint model; LMM, Linear mixed model