Epidemiology of acute rheumatic fever in New Zealand 1996-2005

Aim: Acute rheumatic fever (ARF) and its sequela chronic rheumatic heart disease remain significant causes of morbidity and mortality in New Zealand, particularly among Maori and Pacific peoples. Despite its importance, ARF epidemiology has not been reviewed recently. The aims of this study were to assess trends in ARF incidence rates between 1996 and 2005 and the extent to which ARF is concentrated in certain populations based on age, sex, ethnicity and geographical location. Methods: This descriptive epidemiological study examined ARF incidence rates using hospitalisation data (1996-2005) and population data from the 1996 and 2001 censuses. Rates were compared by using rate ratios and 95% confidence intervals. Results: New Zealand's annual ARF rate was 3.4 per 100 000. ARF was concentrated in certain populations: 5- to 14-year-olds, Maori and Pacific peoples and upper North Island areas. From 1996 to 2005, the New Zealand European and Others ARF rate decreased significantly while Maori and Pacific peoples' rates increased. Compared with New Zealand European and Others, rate ratios were 10.0 for Maori and 20.7 for Pacific peoples. Of all cases, 59.5% were Maori or Pacific children aged 5-14 years, yet this group comprised only 4.7% of the New Zealand population. Conclusion: ARF rates in New Zealand have failed to decrease since the 1980s and remain some of the highest reported in a developed country. There are large, and now widening, ethnic disparities in ARF incidence. ARF is so concentrated by age group, ethnicity and geographical area that highly targeted interventions could be considered, based on these characteristics.