title: Rheumatic Heart Disease Severity, Progression and Outcomes: A Multi-State Model.
abstract: BACKGROUND
  Rheumatic heart disease (RHD) remains a disease of international importance, yet little has been published about disease progression in a contemporary patient cohort. Multi-state models provide a well-established method of estimating rates of transition between disease states, and can be used to evaluate the cost-effectiveness of potential interventions. We aimed to create a multi-state model for RHD progression using serial clinical data from a cohort of Australian patients.
  
  
  RESULTS
  The Northern Territory RHD register was used to identify all Indigenous residents diagnosed with RHD between the ages of 5 and 24 years in the time period 1999-2012. Disease severity over time, surgeries, and deaths were evaluated for 591 patients. Of 96 (16.2%) patients with severe RHD at diagnosis, 50% had proceeded to valve surgery by 2 years, and 10% were dead within 6 years. Of those diagnosed with moderate RHD, there was a similar chance of disease regression or progression over time. Patients with mild RHD at diagnosis were the most stable, with 64% remaining mild after 10 years; however, 11.4% progressed to severe RHD and half of these required surgery.
  
  
  CONCLUSIONS
  The prognosis of young Indigenous Australians diagnosed with severe RHD is bleak; interventions must focus on earlier detection and treatment if the observed natural history is to be improved. This multi-state model can be used to predict the effect of different interventions on disease progression and the associated costs.
authors.affiliation: Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia jeffrey.cannon@telethonkids.org.au.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Cannon
authors.affiliation: Menzies School of Health Research, Royal Darwin Hospital Campus, Darwin, Northern Territory, Australia.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Roberts
authors.affiliation: NT Rheumatic Heart Disease Register, Centre for Disease Control, Darwin, Northern Territory, Australia.
authors.forename: Catherine
authors.initials: C
authors.lastname: Milne
authors.affiliation: Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Carapetis
mesh_terms: D000293:Adolescent; D001315:Australia / Q000453:epidemiology; D058385:Cardiac Valve Annuloplasty / Q000706:statistics & numerical data; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D019918:Heart Valve Prosthesis Implantation / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D015876:Northern Territory / Q000453:epidemiology; D011379:Prognosis; D012214:Rheumatic Heart Disease / Q000401:mortality / Q000503:physiopathology* / Q000601:surgery; D012720:Severity of Illness Index; D055815:Young Adult
keywords: pediatric; prognosis; rheumatic heart disease