Virtual Poster 21st Lancefield International Symposium for Streptococci and Streptococcal Diseases 2022

Risk factors for acute rheumatic fever: a case-control study (#223)

Michael G Baker 1 , Jason Gurney 1 , Nicole J Moreland 2 , Julie Bennett 1 , Jane Oliver 3 , Deborah A Williamson 3 , Nevil Pierse 1 , Nigel Wilson 4 , Tony R Merriman 5 , Teuila Percival 2 , Catherine Jackson 6 , Richard Edwards 1 , Florina Chan Mow 7 , W. Murray Thomson 8 , Jane Zhang 1 , Diana Lennon 2
  1. Department of Public Health, University of Otago, Wellington, New Zealand
  2. Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
  3. Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
  4. Green Lane Paediatric and Congenital Cardiac Services, Auckland District Health Board, Auckland, New Zealand
  5. Department of Biochemistry, University of Otago, Dunedin, New Zealand
  6. Northland District Health Board, Northland, New Zealand
  7. Counties Manukau District Health Board, Auckland, New Zealand
  8. Department of Oral Sciences, University of Otago, Dunedin, New Zealand

Background: Acute rheumatic fever (ARF) and rheumatic heart disease (RHD) are a major and inequitable cause of avoidable suffering and early death in many countries, including among Indigenous Māori and Pacific populations in New Zealand. This study aimed to identify modifiable risk factors, with the goal of producing evidence to support policies and programmes to decrease rates of ARF.

 

Methods: A case-control study was undertaken in New Zealand which recruited hospitalised, first episode ARF cases meeting a standard ARF case-definition. Population controls (ratio of 3:1) were matched by age, ethnicity, socio-economic deprivation, location, sex, and recruitment month. A comprehensive, pre-tested questionnaire was administered face-to-face by trained interviewers.

 

Results: The study included 124 cases and 372 controls. Multivariable analysis identifed strong associations between ARF and household crowding (OR 3.88; 95%CI 1.68-8.98) and barriers to accessing primary healthcare (OR 2.07; 95% CI 1.08-4.00), as well as a high intake of sugar-sweetened beverages (adj. OR 2.00; 1.13-3.54). There was a five-fold higher ARF risk for those with a family history of ARF (OR 4.97; 95% CI 2.53-9.77). ARF risk was similarly elevated following recent skin infections and sore throat.

 

Conclusions: These globally relevent results direct attention to the critical importance of household crowding and access to primary healthcare as strong modifiable causal factors for ARF and potential targets for preventive interventions. They also support a greater focus on the role of skin infections in ARF prevention.