Summary of the latest epidemiology for autoimmune pulmonary alveolar proteinosis (APAP) in Japan

IndicesEstimated (95% CI)
Estimated annual onset in Niigata Prefecture3.9 (1.5–10.2)#
Incidence per 106 population1.65 (0.64–4.31)
Estimated annual cases in all of Japan211 (81–549)+
Estimated survival period years16.1 (15.1–17.1)§
Prevalence per 106 population26.6 (9.6–73.6)ƒ
Estimated number of patients in Japan3387 (1226–9367)##

#: estimated using the Poisson distribution Z(0.975) as the 97.5% quantile of the standard normal distribution. The lower limit is calculated using the equation ((–1×Z(0.975)+(Z(0.975)2+4×event number)0.5)/2)2 and the upper limit using equation ((1×Z(0.975)+(Z(0.975)2+4×event number)0.5)/2)2; : calculated by dividing the Poisson estimate by the population of Niigata Prefecture; +: calculated by multiplying the incidence rate per million by the population of Japan; §: estimated using the restricted mean survival time; ƒ: when the occurrence rate of the disease is stable, the formula prevalence=incidence×mean disease duration (=estimated survival period) is used; ##: calculated by multiplying prevalence rate per million by the total population of Japan.