Table 3

Sensitivity analysis. Net benefit when relative risk and NNTt are varied.



Relative Risk

NNTt
Cut-off for risk of recurrence
0.75
0.8
0.85
0.9

10
10%
-0.00710
-0.0162
-0.02530
-0.03440

25%
0.00880
0.00160
-0.00560
-0.01280

50%
0.01090
0.00620
0.00150
-0.00320
15
10%
0.01043
0.00133
-0.00777
-0.01687

25%
0.01787
0.01067
0.00347
-0.00373

50%
0.01510
0.01040
0.00570
0.00100
20
10%
0.01920
0.01010
0.00100
-0.00810

25%
0.02240
0.01520
0.00800
0.00080

50%
0.01720
0.01250
0.00780
0.00310
25
10%
0.02446
0.01536
0.00626
-0.00284

25%
0.02512
0.01792
0.01072
0.00352

50%
0.01846
0.01376
0.00906
0.00436
33
10%
0.02956
0.02046
0.01136
0.00226

25%
0.02776
0.02056
0.01336
0.00616

50%
0.01968
0.01498
0.01028
0.00558

The relative risk of the intervention is 0.75, the NNTt is 33 and the event rate in the absence of intervention is 20%. The decrease in event rate is the event rate in the population in the absence of intervention minus the event rate in the population when individuals meeting the high-risk definition receive intervention.

Vickers et al. Trials 2006 7:30   doi:10.1186/1745-6215-7-30