The Addis Health and Demographic Surveillance System (Addis-HDSS): Context and Methods

BACKGROUND: Accurate population-based data is essential for evidence-based public health decision-making. Monitoring health events and evaluating interventions through a population-based platform enables timely decisions in rapidly growing urban areas. Such platforms are rare in African countries. This paper outlines the procedures for establishing the Addis Health and Demographic Surveillance System (Addis-HDSS). METHODS: The Addis-HDSS, located in Yeka sub-city of Addis Ababa, Ethiopia, conducted its first census from December 3, 2022, to January 18, 2023. Each enumeration area was identified and mapped digitally. All households in the study area were visited and geocoded. The baseline census gathered data on sociodemographic status, housing conditions, economic status, and selected health-related factors. RESULTS: A total of 30,533 households and a population of 107,494 were recorded. The response rate was 99.1%, reflecting high community engagement. The average household size was 3.5, and the sex ratio was 81 males to 100 females. The population structure resembled a typical lowincome country profile. CONCLUSION: Establishing an urban HDSS was feasible with reasonable effort due to the presence of a digital map and the willingness of the urban population. This surveillance system will be an asset to generate reliable urban health and demographic information by providing an unbiased sampling frame for health-related studies. The HDSS will also be used to test the effectiveness of population-based public health interventions.