Table 4 The sample size needed to show the risk of DVT in relation to air travel
From: The association between air travel and deep vein thrombosis: Systematic review & meta-analysis
Background annual incident rate | Background Weekly incidence rate | Assuming Odds Ratio associated with travelling is | Number of air travellers needed/ week | Number of non air travellers/ week | Events of exposed/ week | Events of unexposed/ week | Extra events in exposed/ week | Total events/ week |
|---|---|---|---|---|---|---|---|---|
1/1,000 | 2/100,000 | 2 | 1,275,418 | 1,275,418 | 52 | 26 | 26 | 78 |
1/1,000 | 2/100,000 | 3 | 392,463 | 392,463 | 24 | 8 | 16 | 32 |