Table 3

Trade-offs between risk and patient outcomes: marginal rate of substitution

Risk of reoperationRisk of complication requiring a new GP/specialist visit
Pain outcomes:
 No daytime pain−34.06***4.01−87.02***17.96
 Moderate daytime pain−25.27***3.18−64.54***14.19
 No night-time pain−39.98***4.72−102.13***22.08
 Moderate night-time pain−25.73***2.86−65.73***13.44
Functional outcomes:
 No difficulty standing−27.65***5.00−70.63***18.62
 Moderate difficulty standing−17.33***3.07−44.28***10.79
 No difficulty moving−20.62***2.43−52.67***12.18
 Moderate difficulty moving−9.72***1.56−24.84***6.09
Risk of complications:
 Risk of new GP/specialist visits0.39***0.06
 Risk of reoperation2.55***0.41
  • The marginal rate of substitution is calculated between one of the risk attributes and each quality of life attribute, by dividing the estimated coefficient of quality of life attribute (pain or function) by the estimated coefficient of risk attribute. Categorical variables for pain and function were coded as dummy variables with ‘severe’ as the omitted reference category. The risk attributes were continuous variables.

  • ***P≤0.01, **P≤0.05, *P≤0.1

  • Coeff, coefficient; GP, general practitioner.