CHANGING PATTERN OF DELAYS IN REPORTING AIDS DIAGNOSIS IN AUSTRALIA

The accurately monitor and predict the progress of the HIV/AIDS epidem ic, it is important to adjust reported AIDS counts for reporting delay s. This requires estimation of the reporting delay distribution. This paper aims to use a statistical model to identify the main factors inf luencing reporting delays in Australis and to adjust reported incidenc e data for these delays among cases of AIDS diagnosed form 1993 and re ported before 30 June 1997. Reporting delays were found to vary signif icantly across states/territories. The influence of calendar time of d iagnosis was also significant, with an overall trend toward longer del ays over time. AIDS cases diagnosed in the fourth quarter of a year we re reported significantly more quickly than those diagnosed in the fir st or third quarters. No significant differences were found due to sex , age and HIV exposure category, except people with haemophilia, in wh om AIDS cases appeared to be reported more slowly. After adjusting for under-reporting and reporting delay, we found that the AIDS incidence in Australia was declining from about 1000 cases per year in 1994 to about 760 cases per year in 1996.