Table 1 Proposed case–control designs and analyses
From: An ongoing case–control study to evaluate the NHS Bowel Cancer Screening Programme
Study | Criterion | Cases | Controls |
|---|---|---|---|
Design 1 | |||
Previous diagnosis | None | None | |
CRA | CRA | ||
Duke A CRC | Duke A CRC | ||
Index diagnosis | Duke B+ CRC | _ | |
Analysis | Exposure to screening prior to first diagnosis of case | ||
Controlling for previous history of CRA & CRC | |||
Adjusting for screen-detection of CRC | |||
Design 2 | |||
Previous diagnosis | None | None | |
CRA | CRA | ||
Duke A CRC | Duke A CRC | ||
Index diagnosis | Duke B+ CRC | _ | |
Analysis | Exposure to screening prior to index diagnosis of case | ||
Controlling for previous history of CRA & CRC | |||
Adjusting for screen-detection of CRC | |||
Design 3 | |||
Previous diagnosis | None | None | |
CRA | CRA | ||
Index diagnosis | Duke B+ CRC | _ | |
Analysis | Exposure to screening prior to index diagnosis of case | ||
Controlling for previous history of CRA | |||
Design 4 | |||
Previous diagnosis | None | None | |
CRA | CRA | ||
Index diagnosis | Any CRC (Duke A-D) | _ | |
Analysis | Exposure to screening prior to index diagnosis of case | ||
Controlling for previous history of CRA | |||
Design 5 | |||
Previous diagnosis | None | None | |
CRA | CRA | ||
Index diagnosis | Any CRC (Duke A-D) | _ | |
Screen-detected | Last screened in same year as case index screen | ||
Analysis | Exposure to screening prior to index diagnosis of case | ||
Controlling for previous history of CRA | |||