From: Interim analysis for binary outcome trials with a long fixed follow-up time and repeated outcome assessments at pre-specified times
Visit number J
Visit time t j
Subjects at risk m j
New events e j
Incidence at visit j d j
0
t 0 (<6 m)
m 0
e0 = 0
d0 = 0
1
t 1 (6 m)
m 1
e 1
d1 = e1/m1
2
t 2 (12 m)
m 2
e 2
d2 = e2/m2
3
t 3 (18 m)
m 3
e 3
d3 = e3/m3
4
t 4 (24 m)
m 4
e 4
d4 = e4/m4