Table 2 Sample Size calculation prognostic value, internal validation [38, 39]
EPV = no. of events/no. of regression coefficients | ||
|---|---|---|
Minimal EPV | ≥10 Prognostic Value | ≥20 Prediction Model |
Change of developing CAI | 30–40% | 30–40% |
No. of regression coefficients | 16 | 16 |
(? = no of events needed) | 10 =?/16 ? = 160 minimal 160 events | 20 =?/16 ? = 320 → minimal 320 events |
In case of 30% chance of developing CAI | 160*3.33 = 532.8 patients | 320*3.33 = 1065.6 patients |
In case of 40% chance of developing CAI | 160*2.5 = 400 patients | 320*2.5 = 800 patients |
Sample Size (incl. 10% loss to follow-up) | 445–593 patients | 889–1185 patients |