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Table 1 Calculation of Number of events prevented in the population (NEPP). Number in the population is 31600, and adherence with therapy 78% in each group.

From: What are the benefits of cognitive enhancers for Alzheimer's Disease: use of Population Impact Measures

Outcome achieved Prevalence of the disease in the population (Pd) Proportion eligible for treatment (Pe) Number given treatment Risk of event of interest in the untreated group (ru) Relative Risk Reduction (95% CI) Number of events prevented in the population** (95% CI)
Cognitive enhancers to all eligible with compliance taken into account
No deterioration* 0.03 0.55 406 0.577 0.527 (0.321, 0.671) 123.6 (82.3, 169.1)
4 point improvement* 0.03 0.55 406 0.268 0.151 (0.01, 0.272) 16.4 (2.1, 31.2)
7 point improvement* 0.03 0.55 406 0.078 0.082 (0.004, 0.154) 2.6 (0.2, 5.8)
Cognitive enhancers to those eligible but not currently treated
No deterioration* 0.03 0.253 187 0.577 0.527 (0.321, 0.671) 66.8 (44.0, 92.6)
4 point improvement* 0.03 0.253 187 0.268 0.151 (0.01, 0.272) 8.9 (1.2, 16.8)
7 point improvement* 0.03 0.253 187 0.078 0.082 (0.004, 0.154) 1.4 (0.11, 3.2)
Treatment of hypertension in the population for those eligible but not currently treated
Development of AD 0.55 0.20 2711 0.005 0.605 (0.229, 0.798) 8.2 (2.3, 16.8)
  1. *in ADAS-cog scale
  2. **applies to 6-month outcome for cognitive enhancers and 1-year for hypertension treatment