Time and expected value of sample information wait for no patient
Simon Eckermann1, Andrew R Willan
1Flinders Center for Clinical Change & Health Care Research, Flinders University, Adelaide, Australia. simon.eckermann@flinders.edu.au
Summary
Accounting for time in clinical trials reduces the expected value of sample information (EVSI) and expected net gain (ENG). This impacts optimal trial design and highlights the opportunity costs associated with delayed decisions.
Area of Science:
- Decision analysis
- Clinical trial design
- Health economics
Background:
- Previous models for EVSI in prospective trials assumed patient populations were time-independent.
- This assumption overlooked the impact of time for trial accrual, follow-up, and analysis on eligible patient numbers.
Purpose of the Study:
- To demonstrate how incorporating time into EVSI calculations affects trial design.
- To quantify the impact of time on the expected value of sample information and expected net gain.
Main Methods:
- Modified the calculation of EVSI to account for the time lag in updating trial evidence.
- Reduced the number of patients benefiting from trial information by those treated during the accrual, follow-up, and analysis periods.
Main Results:
- Accounting for time reduces the eligible patient population for EVSI calculations.
- Both EVSI and ENG are lower when time is considered, especially with delayed decisions and opportunity costs.
- Trial size impacts the reduction in eligible patients due to accrual time.
Conclusions:
- Properly accounting for time in trial design reduces EVSI and increases opportunity costs.
- Delayed trials are less likely to be optimal, suggesting smaller, more efficient trial designs.
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