Solved – How to calculate 95% CI for cumulative incidence rate using R

confidence intervalincidence-rate-ratior

for example, 30 events during 10000 person-years, the cumulative incidence rate is 3 per 1000 person-years, how to calculate its 95% CI?

Best Answer

This sounds like an incidence rate not cumulative incidence, which is a risk (number of cases divided by original disease-free population). Presumably the 95% CI for cumulative incidence is the same as that for any proportion. If you are after the 95% confidence interval for a rate it is given by:

ln(95%CI) = ln(rate)+/-1.96SE [1]

where SE is defined by

1/sqrt(d) [2]

where d is the numerator size.

Exponentiate [1] to give you the lower and upper bounds.

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