Parameters | Re-examine POPI trial | Generic sample size calculation | Source | |||
---|---|---|---|---|---|---|
 | Baseline values | Range | Baseline values | Range |  | |
Sample size calculation | Â | Â | Â | Â | Â | |
inc | PID incidence (per year) | 1) 2 % & 2) 3 %a |  | calculated†|  | POPI trial [14] |
RR | Relative risk | 1) 0.48 & 2) 0.44a | Â | calculateda | Â | POPI trial [14] |
t | Follow-up time (in days) | 365 |  | 365 | 90–540‡ | POPI trial [14] |
α | Significance level | 5 % |  | 5 % |  | POPI trial [14] |
1-β | Power | 80 % | 10–90 %†| 80 % |  | POPI trial [14] |
Infection parameter | Â | Â | Â | Â | Â | |
λ | Force of infection (per day) | calculated§ |  | calculated§ |  |  |
1/r | Duration of infection (in days) | 365 | 365 ± 75 | 365 | 365 ± 75 | Model [17]¶ |
p | Prevalence of infection | 7 % | 3–10 %‡ | 7 % | 3–10 %‡ | POPI trial [14] |
Progression to PID | Â | Â | Â | Â | Â | |
f | Fraction of women with chlamydia who progress to PID in absence of testing | calculated†|  | 10 % | 7–13 % | Model [16]¶ |
1/γ | Infection progression (in days) | calculated# |  | calculated# |  |  |