Supplementary Material for: Burden of glomerular diseases in Australia: a data linkage study

Introduction. Glomerular diseases are rare but associated with substantial morbidity. Existing studies focus mainly on kidney failure and mortality, often overlooking multi-system complications. This first Australian, population-based study uses linked routinely collected health data to estimate incidence, prevalence, and long-term outcomes, capturing cardiovascular, thrombotic, infectious, and healthcare burdens.

Methods. We conducted a population-based cohort study of adults ≥45 years in New South Wales, Australia (2005-2009, n=267,357), using the 45 and Up Study with probabilistic data linkage via CHeReL and the Sax Institute. Glomerular disease was identified using nephrology specialist reviews, ICD-10-AM codes, kidney biopsy procedure codes, and the Australian and New Zealand Dialysis and Transplant (ANZDATA) registry. Age-standarised glomerular disease prevalence and incidence were estimated. Kaplan-Meier curves and Cox regression models evaluated all-cause mortality, major cardiovascular events (MACE; composite of acute myocardial infarction (AMI), stroke, and all-cause mortality), venous thromboembolism, and any hospitalised infection. Subdistribution hazard models assessed kidney replacement therapy (KRT) risk, accounting for the competing risk of death.

Results. We identified 365 participants with glomerular disease (n=195 prevalent, n=170 incident; 67% male, mean age 65 years). The age-standardised prevalence and incidence of glomerular disease was 89/100,000 persons and 12/100,000 person-years-at-risk, respectively. After a median follow-up of 6 years, prevalent disease participants had a higher adjusted risk (HR; 95% CI; all P-values <0.001) of all-cause mortality (2.18; 1.60–2.99), KRT (31.3; 12.7–77.2), MACE (2.17; 1.59–2.96), AMI (3.84; 2.05–7.20), stroke (3.58; 1.69–7.56), venous thromboembolism (2.93; 1.76–4.89), and any hospitalised infection (2.92; 2.42–3.54). The 5-year risk of complications was comparable between prevalent and incident cases. Hospitalisation burden was also significantly higher among glomerular disease participants (P<0.001).

Conclusions. Using linked data, this study reveals the substantial multi-system burden of glomerular diseases, including kidney failure, death, cardiovascular events, infections and hospitalisations in adults aged 45 and over.