Excess mortality among people with communicable diseases over a 30-year period, Victoria, Australia: a whole of population cohort study

Stacey L Rowe; Karin Leder; Lalitha Sundaresan; Dennis Wollersheim; Jock Lawrie; Nicola Stephens; Benjamin C Cowie; Terry M Nolan; Allen C Cheng

doi:10.1016/j.lanwpc.2023.100815

Excess mortality among people with communicable diseases over a 30-year period, Victoria, Australia: a whole of population cohort study

Lancet Reg Health West Pac. 2023 Jun 20:38:100815. doi: 10.1016/j.lanwpc.2023.100815. eCollection 2023 Sep.

Authors

Stacey L Rowe^{1

2

3}, Karin Leder¹, Lalitha Sundaresan⁴, Dennis Wollersheim², Jock Lawrie², Nicola Stephens⁵, Benjamin C Cowie^{6

7}, Terry M Nolan^{8

9

10}, Allen C Cheng^{1

11}

Affiliations

¹ School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
² Department of Health, Melbourne, Victoria, Australia.
³ University of San Francisco, California, USA.
⁴ Mathematica, Oakland, California, USA.
⁵ The University of Tasmania, Hobart, Tasmania, Australia.
⁶ WHO Collaborating Centre for Viral Hepatitis, Doherty Institute, Melbourne, Victoria, Australia.
⁷ Department of Infectious Diseases, University of Melbourne, Parkville, Victoria, Australia.
⁸ Murdoch Childrens Research Institute, Parkville, Victoria, Australia.
⁹ Vaccine and Immunisation Research Group (VIRGo), Parkville, Victoria, Australia.
¹⁰ Peter Doherty Institute for Infection and Immunity at The University of Melbourne, Parkville, Victoria, Australia.
¹¹ Monash Infectious Diseases, Monash Health, Clayton, Victoria, Australia.

Abstract

Background: Understanding mortality burden associated with communicable diseases is key to informing resource allocation, disease prevention and control efforts, and evaluating public health interventions. We quantified excess mortality among people notified with communicable diseases in Victoria, Australia.

Methods: Cases of communicable disease notified in Victoria between 1 January 1991 and 31 December 2021 were linked to the death registry. Informational gain obtained through linkage and 30-day case fatality rates were calculated for each disease. Standardised mortality ratios (SMR) and 95% confidence intervals were calculated up to a year following illness onset.

Findings: There were 1,032,619 cases and 5985 (0.58%) died ≤30 days of illness onset. Following linkage, the 30-day case fatality rate increased more than 2-fold. Diseases with high 7-day SMR signifying excess mortality included invasive pneumococcal disease (167.7, 95% CI 153.4-182.7); listeriosis (166.2, 95% CI 121.2-218.3); invasive meningococcal disease (145.9, 95% CI 116.7-178.3); legionellosis (43.3, 95% CI 28.0-62.0); and COVID-19 (21.9, 95% CI 19.7-24.3). Most diseases exhibited a strong negative gradient, with high SMRs in the first 7-days of illness onset that reduced over time.

Interpretation: We demonstrated that the rate of death in Victoria's notifiable disease surveillance dataset is underestimated. Further, compared to a general population, there is evidence of elevated all-cause mortality among people notified with communicable diseases often up to one year following illness onset. Not all elevated risk is likely directly attributable to the communicable diseases of interest, rather, it may reflect underlying comorbidities or behaviours in these individuals. Regardless of attribution, infection with communicable diseases may represent a marker of mortality. Key to preventing deaths may be through timely and appropriate transition to primary and preventive healthcare following diagnosis.

Funding: No funding was provided for this study.

Keywords: Communicable diseases; Infectious disease; Mortality; Public health.