ATYPICAL HAEMOLYTIC URAEMIC SYNDROME IN AUSTRALIA: REAL-WORLD CHALLENGES AND LESSONS FROM THE THROMBOTIC MICROANGIOPATHY REGISTRY

KJ ROBSON1, NM ISBEL2, TD BARBOUR3, EM WOOD4, JY KAUSMAN5,6,T DE MALMANCHE7,8, PA BLOMBERY9, PD HUGHES3, L KIVIVALI4, Z MCQUILTEN4, SJ COHNEY1

1Western Health, Melbourne; 2University of Queensland at Princess Alexandra Hospital, Brisbane; 3Royal Melbourne Hospital, Melbourne; 4Department of Epidemiology & Preventive Medicine, Monash University, Melbourne; 5Royal Children’s Hospital, Melbourne; 6Murdoch Research Institute, RCH, Melbourne; 7School of Medicine & Public Health, University of Newcastle, Newcastle; 8Pathology North (Hunter) Immunology, Newcastle; 9Peter MacCallum Cancer Centre, Melbourne

Aims: To characterize clinical presentations, genetic variants, treatment, and outcomes in Australian patients with aHUS. To highlight current diagnostic and therapeutic practices, and to identify potential areas for improvement
and research.

Background: Registry data is critical in furthering our understanding of aHUS, a rare, life-threatening disease. This is the first report on patients with aHUS from the Australia & New Zealand TMA registry (established 2009).

Methods: Registry data from June 2009 to January 2016 were reviewed. Cases registered as ‘aHUS’ were correlated with the original medical record by a single investigator. Data were analysed with descriptive statistics, and subgroups compared using Mann-Whitney U test.

Results: 38 patients with aHUS were included: 32 adults, 6 children. 6/38 presented after solid-organ transplant, and 5/38 after exposure to a drug associated with TMA. ADAMTS13 activity was >10% in the 24/38 cases where it was measured. Thrombocytopenia and renal impairment were less severe in post-transplant and drug-associated cases compared with the remainder of the cohort. 18/38 (47%) patients underwent dialysis; 2 remained dialysis-dependent at follow-up, 4 underwent subsequent renal transplantation. Complement gene analysis was performed in 14 cases, with 10 risk variants identified in 9 patients. Plasma exchange (PEx) was provided in 30/38 (79%) cases. PEx duration was significantly longer in cases without measured ADAMTS13 activity (median 15 vs. 4.5 days, p=0.04). 23 patients received eculizumab; 16/23 were treated during first admission.

Conclusions: Characteristics of Australian patients with aHUS were similar to other reported cohorts, but subgroup analysis revealed significant differences between post-transplant, drug-associated, and other cases. This study identified practical challenges in diagnostic workup and treatment of aHUS in Australia, highlighting areas for potential improvement in patient care.

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