The value of reusing prior nested case-control data in new studies with different outcome

Area of Science:

• Epidemiology
• Biostatistics

Background:

• Nested case-control (NCC) studies offer cost-efficiency in epidemiological research.
• Reusing prior NCC data for secondary outcomes is methodologically challenging due to sampling designs.

Purpose of the Study:

• To provide practical guidelines on reusing prior NCC data to complement controls in current studies.
• To assess the effectiveness and power gains of using a mixture of prior and newly sampled subjects.

Main Methods:

• Utilized simulated cohorts to evaluate NCC study efficiency with mixed control sources.
• Introduced the concept of 'effective number of controls' to quantify power gains.
• Applied the methodology to real-world data for anorexia and contralateral breast cancer.

Main Results:

• Study efficiency depends on the number of new controls, prior subjects, and overlap in matching variables.
• Demonstrated that prior data can effectively substitute for newly sampled controls.
• Showcased power calculation methods using publicly available software.

Conclusions:

• Reusing prior NCC data is feasible and can significantly improve study efficiency and power.
• The 'effective number of controls' framework aids researchers in optimizing resource allocation.
• This approach is particularly valuable for genetic and molecular epidemiology with expensive measurements.