Sociodemographic and geographical inequalities in notifiable infectious diseases in Australia: a retrospective analysis of 21 years of national disease surveillance data

Abstract

Background: Australia is a high-income country with a well established and largely publicly funded health-care system. However, some populations within Australia have shorter life expectancy and worse health outcomes than others. We explored geographical variations and sociodemographic inequities in infectious disease notifications in Australia.

Methods: In this retrospective study, we analysed National Notifiable Diseases Surveillance System (NNDSS) notifications from 1991-2011 (n=2·4 million). We assessed the effect of socioeconomic disadvantage and remoteness of residence on national notification incidence. We calculated Gini coefficients, adjusted relative risks (aRRs), population attributable fractions (PAFs), and attributable notifications. We reported aRRs for Indigenous status in three jurisdictions with more than 75% completeness of Indigenous status reporting from the Northern Territory, South Australia, and Western Australia.

Findings: Of the eight most commonly notified diseases from Jan 1, 1991, to Dec 31, 2011, gonococcal infection was the most geographically unequal and campylobacteriosis was the most evenly distributed across the country. Overall, notification incidence was higher in remote and very remote areas than in major cities (aRR 3·37), and higher in the most socioeconomically disadvantaged quintiles compared with less disadvantaged quintiles (aRR 1·15). The PAF for socioeconomic disadvantage was high for blood-borne viral hepatitis but decreased in other disease groups. In 2011, sexually transmitted infections had 11 093 notifications attributed to remoteness and 5597 notifications attributable to socioeconomic disadvantage. Notification incidence was higher in Indigenous than in non-Indigenous Australians (aRR 5·3).

Interpretation: All diseases had differing geographical concentration and sociodemographic risk. Overall, sociodemographic inequities in infectious disease notifications have decreased, but remain unacceptably high. National communicable disease control is complex, requiring both targeted and population-wide interventions.

Funding: None.